ALBERT R. MANN 
 LIBRARY 
 
 AT 
 
 CORNELL UNIVERSITY 
 
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 http://www.archive.org/details/cu31924051795437 
 
BRITISH 
 
 FRESH- V\^ATER ALG^. 
 VOL. I. 
 
BRITISH 
 
 FRESH-WATER ALG^ 
 
 EX0LT7SIVE OP 
 
 DESMIDIE^ AND DIATOMAOB^. 
 
 M. C. COOKE, M.A., LL.D., A.L.S., 
 
 Author of "Handbook of British Futigi" ** Mycographia," "Illustrations 
 of British, Fungi," ^x,, ^x. 
 
 VOL. I. TEXT. 
 
 WILLIAMS AND NORGATE, 
 
 HBNEIETTA STEEET, COVENT GAEDEN, LONDON; 
 
 SOUTH FEEDEEICK STEEET, EDINBUEGH. 
 
 LEIPZIG : F. A. BEOCKHAUS. NEW TOEZ : WESTEEMANN & CO. 
 
 1882—1884.. 
 
r "" 
 513 
 
 ' V. / 
 
 CORNELL 
 
 UfSilVERSITY 
 
 LIBRARV 
 
BEITISH FEESH-WATEE ALGJl. 
 
 INTRODUCTION. 
 
 " Fresh-Water Alg^ " is confessedly an artificial arrange- 
 ment which demands apology, but can scarcely receive 
 justification. The only excuse which can be offered is, that it 
 serves the purpose of those for whom the present work was 
 written, namely, the Microscopists who desire some acquaint- 
 ance with the organisms met with in their excursions to ponds 
 and ditches. For the absolutely scientific algologist it will 
 only be fragmentary, although it is by no means a solitary in- 
 stance in which the Fresh-Water Algaj have been made the 
 sole subject of a book, to the exclusion of marine species. 
 Indeed, the restriction of Harvey's " Phycologia Britannica " 
 to marine algse, with but very few exceptions, left at least an 
 excuse for attempting to supply the deficiency. 
 
 The historical portion of this introduction may be speedily 
 summarized by dividing it into three epochs of about forty years 
 each, the first being limited by the publication of Dillwyn's 
 " Confervse," the second by Hassall's " Fresh-Water Algse," 
 and the third by the present work. 
 
 Prior to the first epoch there were but two works of sufficient 
 
11 INTRODUCTION. 
 
 importance to be mentioned here, Eay's " Synopsis," whicli 
 was published in 1724, and Dillenius' " Historia Miiscorum " 
 in 1741. Each of these, as far as they can be identified, 
 included somewhere about twenty species of Fresh-Water 
 Algae. 
 
 The epoch commences in reality with Hudson's " Flora 
 Anglica," the first edition of which is dated 1762, and contains 
 about 25 species. Then came the first Edition of Withering's 
 " Arrangement of British Plants " in 1776 ; Lightfoot's 
 "Flora Scotica" in 1777, also with 25 species; Eobson's 
 "British Flora" in the same year, with 26 species; the 
 second Edition of Hudson's " Flora Anglica " in 1778 ; 
 Eelhan's " Flora Cantabrigensis " in 1785, with 12 species ; 
 and Sibthorp's " Flora Oxoniensis " in 1794, with 7 species. 
 This brings us to the third Edition of Withering in 1796, with 
 38 species ; followed by Abbot's " Flora Bedfordiensis " in 
 1798, with 14 species ; and Hull's " British Flora " in 1799, with 
 34 species. These were all the predecessors of Dillwyn, and did 
 not achieve much, for the Fresh- Water Algse until the climax 
 was attained by the publication of Dillwyn's " British Con- 
 fervas " in 1809, with 88 species enumerated. The first Edition 
 of " English Botany " had already commenced in 1790, ex- 
 tending to 1814, but it was not until after the appearance of 
 Dillwyn's work that the AlgEe of the British Botany were 
 published, ultimately including about 100 species. Undoubtedly 
 Dillwyn was therefore the parent of a systematic study of the 
 British Fresh-Water Algas, and with him the first epoch 
 culminated. 
 
 The second epoch commenced well with the continuance of 
 " English Botany," and then followed several Botanists whose 
 influence has passed down even to our own times. Following 
 the example of the first epoch, we may enumerate the most im- 
 portant of their works. The " Midland Flora " of Purton in 
 1821 only includes about 14 species. Hooker's " Flora 
 Scotica " in 1821 about 39 species ; Gray's " Arrangement " 
 in 1824, was confessedly devoted chiefly to systematic classifica- 
 tion, including nominally 103 British Fresh-Water Algae. 
 Greville'B " Flora Edinensis " in 1824 had 50 species, the 
 
INTBODUOTION. Ill 
 
 working period for Algje having scarcely commenced, his 
 " Algse Britannic^ "appearing in 1830. Jones and Kingston's 
 " Flora Devoniensis" in 1829 included but 29 species. John- 
 ston's "Flora of Berwick-on-Tweed " in 1831 had 40 species. 
 Near this time (1833) Berkeley's "Gleanings of British 
 AlgEB " was published. The latter volumes of " The English 
 Flora" appeared also in 1833, under the editorship of Sir 
 William Hooker, the Algse being contributed by Dr. W. H. 
 Harvey, and included 160 species. This was Harvey's first im- 
 portant contribution to the History of British Algse, which was 
 succeeded in 1841 by the first Edition of his " Manual," con- 
 taining 198 fresh water species. Between these two Mackay's 
 " Flora Hibernica '' was issued in 1836, with 87 Irish species. 
 These all culminated, in 1845, in the appearance of Hassall's 
 " Fresh- Water Algse," enumerating 297 species, exclusive of 
 CharacesB, Desmidiacese, and Diatomaoese, thus closing the 
 second epoch. The time at which this latter work appeared was 
 an active one in British Fresh-Water Algse. Ralfs was preparing 
 his work on Desmids, and contributing papers to the scientific 
 journals, notably the " Annals of Natural History." Dr. 
 Greville had commenced his " Scottish Cryptogamic Flora " in 
 1823. Harvey was at work earnestly with Marine, and of course 
 casually with Fresh- Water Algse. The volume containing the 
 Algse of the " English Botany,'' second Edition, appeared in 
 1844, so that about this time, which we distinguish as the end 
 of the second epoch, characterised by the publication of 
 Hassall's work, there was greater promise than came to be rea- 
 lized in the early part of the next epoch. 
 
 It is not uncommon to hear observations made disparagingly 
 of the work with which the second epoch closed, when no 
 account is taken of the difficulties which had to be encountered 
 in preparing an illustrated work of that nature. It cannot be 
 fair to judge it by its successors, but by its predecessors, and if 
 it was fairly up to the general standard at the time of its pro- 
 duction, that is all we can expect. It must be remembered that 
 Kutzing's large and splendid work, the " Tabulas Phycologi*," 
 was only commenced in 1846, and that therefore it could not be 
 consulted. It is certainly to be regretted that in Hassall no 
 indication is given of the measurement of the objects figured, or 
 
INTRODUCTION. 
 
 the magnification employed. That there are faults no one will 
 deny ; but, on the whole, we are not prepared to condemn it as 
 unworthy of the time at which it appeared. A comparison of 
 the Desmids with those in Ralfs' work, of but three years 
 later, will show that in execution something was left to be 
 desired. 
 
 The third epoch is one on which we must necessarily be very 
 brief; coming so near our own time we must be content to in- 
 dicate what has been done, and leave conclusions to others. 
 Closer relations with the Continent, cheap postage, more general 
 acquaintance with foreign works, all tend to raise greater expec- 
 tations for the closing work of the third epoch than of its pre- 
 decessors. The works of Kutzing, the Memoirs of Pringsheim, 
 De Bary, Cohn, Bornet, Thuret, Borzi, Wittrock, and many 
 others, all contribute to illustrate British Fresh-Water Alges ; 
 and although during forty years very little has been done in our 
 own island, even in the identification of species, there has been 
 considerable activity in investigation, especially in the North of 
 Europe. The scattered memoranda, notes and observations of 
 Professor Henfrey, Dr. Braxton Hicks, and Mr. W. Archer 
 constitute the bulk of our home manufacture of the literature of 
 Fresh-Water Algse for about 30 years. The later portions of 
 the " Supplement to English Botany," containing Algae, date 
 from 1843 ; and Harvey's second Edition of the " Manual," in 
 1849, was wholly confined to Marine species. Hence there is 
 not an independent work on British Fresh- Water Alga belonging 
 to this third epoch, the only contributory work being Berkeley's 
 " Introduction to Cryptogamic Botany," in 1857. But if there 
 was an extraordinary dearth of books on this subject after 1845 
 in Britain, such was not the case on the Continent. The con- 
 secutive publication of the volumes of Kutzing's " Tabulae " 
 must have been an important influence, although it was not 
 until 1864 that Eabenhorst's " Flora Eiiropsea Algarum, Aquaj 
 Dulcis et Submarine " was commenced. The advent of this 
 work was hailed with pleasure, notwithstanding its many faults; 
 and various authors set themselves to work on different genera 
 and families, such as iEdogcniaceje, Zygnemacese, &c., so that 
 in twenty years it is left far behind. As a work written in Eng- 
 lish, although not containing much original observation, we 
 
INTRODUCTION. 
 
 must mention Dr. Horatio Wood's " Fresh-Water AlgK of 
 North America," published in 1872. The period selected, 
 therefore, for a new work on the " British Fresh-Water Alg» " 
 was in all respects opportune, but we are not expected to judge 
 whether good use has been made of the opportunity. 
 
 The gradual accession to knowledge of the structure and 
 development of Algse, during the past century, would extend 
 this chapter far beyond the limits we hare assigned to it, 
 whereas an intimation of the present position is generally indi- 
 cated under the several groups, in the body of the work, with 
 some reference to the sources of further information. 
 
 Classification must, of course, depend very largely upon 
 investigation, and modifications necessarily follow new facts, so 
 that, whilst adopting suggestions made by authors of recent 
 monographs, our arrangement is not absolutely that of any 
 other work, although as far as possible the orders and larger 
 groups have not been disturbed. We will not venture to pre- 
 dict what will be the future of such families as the Palmellacece, 
 Protococcacece, and Chrooeoccacece during the next twenty years; 
 probably they will disappear altogether, becoming merged into 
 other groups of which most of them may be demonstrated to be 
 only imperfect conditions. At the present time we could follow 
 no other course than to include them, and leave the future to 
 take care of itself. We have preferred including too much to 
 excluding too much, in confidence that for this we should be 
 the more readily forgiven. 
 
 The student will expect to find in this place some practical 
 hints to guide him in his pursuit, but these must be brief, as 
 experience, combined with a little personal contact with old 
 hands at field-work, will supersede a volume of precepts. 
 
 The habitats attached to the various species will indicate 
 the kind of locality in which to search for them, but it may be 
 remarked that, generally, any slow stream, pond, or standing 
 pool will furnish something. Eapid currents will not repay the 
 search. Small pools on moors, amongst Sphagnum, will usually 
 prove prolific, and submerged plants, especially when dead or 
 dying, often serve as a habitat for attached species. Damp 
 rocks, down which the water trickles, old quarries, damp walls 
 
VI INTRODUCTION. 
 
 in greenhouses and hothouses, warm springs, outlets of warm 
 water from steam engines, brackish ditches, all these have their 
 own peculiar forms, and experience will soon prove that where 
 the favourable condition of quiet humidity is found, search will 
 seldom be in vain. Of course, during exceptionally dry 
 weather localities which would otherwise give satisfaction may 
 produce nothing but disappointment. 
 
 The methods of collecting do not much differ from those 
 adopted for other kinds of pond life. A japanned case with 
 from six to twelve corked test tubes will usually suffice for a 
 day's collecting. Filamentous Algse, such as Spirogyra, Glado- 
 phora; &c., may be wrapped singly in paper, and a number of 
 these packets can be contained in a small tin box. It is always 
 essential to keep each " gathering "by itself. 
 
 Preservation for future study, or for the herbarium, will be 
 secured by the usual methods of floating and mounting marine 
 Alg», first cleansing the specimens by well washing in a flat 
 dish or soup-plate, and finally passing under them a slip of 
 clean white paper, which is raised so as to take up the Algse in 
 the middle, well floated into position, draining off the water, 
 and then drying, with the least pressure possible. For minute 
 species, and small specimens, thin flakes of mica are preferable 
 to paper, for many reasons, especially that they can be placed at 
 any time under the microscope and examined. The Palmel- 
 lacecB, and similar groups, will be of very little service if dried 
 in any other way. Most species will adhere of themselves to 
 either paper or mica, the exceptions, such as Vaucheria and some 
 Cladophorce, can be fixed with gum tragacanth. 
 
 Some difficulty may probably be experienced in mounting 
 satisfactorily specimens for the microscope. We have seen 
 " slides " in which the specimens were still green and life-like 
 after having been mounted for twelve years in the water in 
 which they were collected, but unfortunately there is always a 
 risk of leakage with mounts in fluid, If the medium is denser 
 than ,the contents of the Algse cells, the endochrome will be 
 contracted and the walls collapse. One objection to mounting 
 in glycerine, or glycerine and water, is the density of the 
 medium, and consequent collapse of the cells ; another, that in 
 
INTRODUCTION. ■ VU 
 
 time, use what precaution you may, the cells will leak, more or 
 less, in the majority of instances. No medium has yet given 
 us absolute satisfaction, but all things being considered, we are 
 most favourably disposed towards glycerine jelly, which is too 
 dense to enter the cells, and does not alter the form more than 
 glycerine would do. We may add that the slides should always 
 Mejlat in the cabinet, and not on edge, and they should not be 
 left exposed to the light, or the green colour will soon be lost. 
 
 Hints for cultivating in growing cells, or preservation in 
 small aquaria, are scarcely necessary in these days of manipu- 
 lation. Many forms of growing slides have been designed 
 and described, each possessing some special advantage, and 
 arrangements of common glass tumblers, communicating with 
 each other by small syphons, or lax threads, will keep up a 
 constant flow of water, sufficient to preserve Algse living and 
 thriving throughout the year. The life-history, changes, and 
 development of many species still require to be patiently inves- 
 tigated, and for this purpose there are ample contrivances, all 
 that is required being leisure, patience, and perseverance. 
 
 It can scarcely be necessary to insist on the presence of fructi- 
 fication, if a given species is to be accurately determined. This 
 is especially the case in CEdogoniacece and Zygnemacece, but it 
 applies also in a less degree to the majority of families. The 
 great difficulty that is experienced in determining, with any 
 approximation to accuracy, many of the species described by 
 authors half a century ago, lies in the insufficiency of the cha- 
 racters of the fructification. A large number of species of 
 (Edogonium, for instance, as recent as Hassall's work, cannot be 
 definitely placed on account of this insufficiency. This may at 
 the same time serve as a caution to the inexperienced, that it 
 will be worse than useless attempting to affix a name to speci- 
 mens collected in a young or imperfect condition, at any rate in 
 genera the fructification of which is known, and embodied in 
 the generic and specific characters. 
 
 Although it can hardly be considered essential to allude in 
 this place to theories which have been propounded in connection 
 with Fresh-Water Algae, we may make a passing allusion to 
 the suggestion that sexually distinct filaments exist in the 
 
VIU INTRODUCTION. 
 
 Zygnemacem, and meet it by the assertion that, as far as our 
 experience goes, this suggestion is not supported, and the 
 evidence produced is far from satisfactory. The larger and 
 more complex hypothesis of the combination of Alga and Fungi 
 in the production of Lichens, has been combated elsewhere,* 
 and to this we have nothing to add, save that we have since 
 encountered no facts or arguments which would induce us to 
 modify that opinion. Even should hereafter the terrestrial 
 Nostocs be united with the Collemacece, the saxicolous Stigo- 
 nemeoB be relegated to the Sirosiphei, and the corticolous 
 ChroolepidcB be transferred to some other relationship, the true 
 aquatic Algee would still remain in sufficient number to interest 
 the student, and maintain for some time to come the distinctive 
 group of Fresh- Water Algse. 
 
 * '< Grevillea," Vol. vii., p. 102. 
 
BRITISH 
 
 FRESH-WATER ALG^.* 
 
 AlgsB are usually associated under five classes, which are 
 taken invariable order, according to the judgment of the author, 
 and may thus be enumerated : — 
 
 I. Chlorophyllophyce^, vfith the. cell contents mostly of a 
 chlorophyll green. 
 
 II. PHYOocHROMOPHYCB^ffii, with the cell contents mostly of a 
 bluish green. 
 
 III. Melanophyob^, with the cell contents olive, brownish, 
 or blackish. 
 
 IV. Rhodophycb^, with the cell contents rosy, purple, 
 crimson or violet. 
 
 V. DiATOMOPHYCEiE, with an incombustible siliceous skeleton. 
 
 Other arrangements have been proposed, but the above will answer for 
 all practical purposes. The third class are all marine, and the majority 
 of the fourth, so that, exclusive of Diatoms, which are a special study, 
 the fresh water Algae are mainly included in the first two classes. 
 
 Class I. CHLOROPHYLLOPHYOE^. 
 
 Plants aquatic or aerial, one, or two, or many-celled, either 
 single or associated in families. Either branched or simple. 
 Cell wall not siliceous but combustible, sometimes composed of 
 successive layers, or strata, of a gelatinous substance. Cell 
 contents chlorophyllose, sometimes crimson, flesh-coloured or 
 reddish-brown, often with a central or lateral nucleus. Starchy 
 granules very rare. Vegetation by cell division. Fecundation 
 often sexual. Propagation either by oospores or zygospores or 
 gonidia, which are motionless or agile {zoogonidia). — Babh. 
 Alg. iii. p. 1. 
 
 * Exclusive of Desmidiese and DiatomaceEe. 
 
Z COOCOPHYCE^. 
 
 Order I. COGCOPHTCE^. 
 
 Unicellular algse. Cells either single, or many associated in 
 families, tegument involute or naked, destitute of branches or 
 terminal vegetation. Propagation by cell-division or zoogo- 
 nidia. 
 
 This order includes the two families Palmellacem and ProtoeoccaeecB, 
 with unmoveable cells, to which is attached a third, the Volvocmece, with 
 mobile cells. The two former correspond to the Chroococcaoew amongst 
 the class Phycochrnmacece. Although thus removed, it would seem from 
 recent researches, that there is,' in some sort, a relationship between the 
 PabmellaeecB and Protocnccaceiz on the one hand, and the Chroococcaoeie 
 on the other. 
 
 We can only direct attention here to the papers by P. Riohter, in 
 "Hedwigia,' (xix., 1880, p. 154) on fflwocystis and (xix. 1880, p. 169 
 and 191), on the " genetic Connection of certain Unicellular Phycoclu 
 romacem" of which abstracts were published in the " Royal Microsco- 
 pical Journal."* 
 
 The conclusions arrived at are in favour of a sort of polymorphism. 
 
 " The lowest form of the Phycoohromacese is the naked ApTioimcwpsa 
 condition, corresponding to Palmella among the Chlorophyllophycese. 
 From this naked or only slightly encysted condition is developed the 
 6lceocapsa or Olmocystis form with several gelatinous envelopes ; the 
 Chroococciis type, when the investment is altogether wanting, or, when 
 there is only a single vesicular envelope, the csenobium types. The 
 GlcBOcapsa type is specially adapted for exposure to the air, and growth 
 upon a comparatively dry substratum ; the caenobium type is developed 
 in water ; theChrooeocceits type in water, or on a moist substratum in 
 the air. With this is connected the cylindrical form, a higher stage, 
 because it displays a differentiation in the direction of growth, and a 
 development towards the filiform condition. This is not always de- 
 veloped, and may be distinguished into stable and unstable forms j the 
 latter may occur In two or three varieties, and may go through the 
 following successive conditions : — 
 
 1. — Stable Aphanoeapsa and Palmella. 
 
 2. — Aphanoeapsa and Palmella which have attained to GlcBooapsa, 
 GlcBoeyitis, or csenobium type, but which always revert to the naked 
 solitary spherical form. 
 
 3. — Stable Glcenoapsa, Glceocystis, Cli/roocoocus, and caenobium forms, 
 without reversion ( Merismopedia) , 
 
 4. — Cylindrical forms, the generations of which pass through the 
 solitary spherical CAphanocapsa and Palmella) condition, as well as the 
 Glmoeapm and similar forms. 
 
 5. — Cylindrical forms, which pass through only the Gloeoeapsa and 
 similar forma. 
 
 6. — Cylindrical forms the generations of which revert to the Aphano- 
 eapsa and Palmella condition, while the Glceoeapsa or any similar form 
 is suppressed. 
 
 7. — Stable cylindrical forms CSynechoeoccusJ. 
 
 No reference is made in the above to the passage of Glceoeapsa into 
 the encysted filiform conditions of Svrosiphon corresponding to Palmo- 
 daetylon and Hormospora among the GhlorophyllophyoeBB." 
 
 * Vol. I., Second Series, 188i pp. 98 and 201. 
 
PALMELLAOB^. 3 
 
 Family I. PALMBLLAOE^. 
 
 Unicellular algse, in the broadest sense. .Cells either solitary, 
 or more or less numerous, associated in families, vegetating by 
 cell-division, propagation by gonidia, which are produced from 
 the ultimate generation of cells. Gonidia, when free, ciliate 
 (usually with a paiT of cilia) actively mobile. 
 
 Genus 1. EREMOSPHiERA. Be Bary. (1858.) 
 Cells single, rather large, swimming free, spherical, cell wall 
 firm, with a hyaline border. Cell contents {Cytioplasma) green, 
 granulose, sometimes containing green lamina disposed in a 
 radiate manner. Multiplication of the cytioplasm by division 
 into two or four (or more) sister cells, which escape by the 
 rupture of the cell-wall {Cyiiodei-m^ 
 
 Eiemosphaeza vizidis. BeBy. Conj.p. 56, t. viii./. 26, 27. 
 
 Cells globose, large, of a beautiful grass green. — Rabh. Alg. 
 iii. p. 24. 
 
 Chloroaphaera Oliveri, Henfr. Trans. Micr. Soc. yii. p. 25 
 (1859), pi. 3. Kirch. Alg. Schl. p. 115. 
 
 Size, •0043--0059 in. == -Il-'IS mm. (Rabh.), •1--12 mm. 
 {M.C.C.). 
 
 In boggy ditches, 
 
 " The ordinary appearance of the plant is that of a large green globe, 
 like a large spore, lying free in the water, or often gathered in loose 
 groups npon decaying vegetable struoturea, aiioh as leaves of Sphagnum 
 contained in the water. The globe is a single simple cell, with a thin 
 membranous coat surrounding a mass of nsaally green granular con- 
 tents. Each cell produces two, or more rarely, four new ones." — 
 
 Plate I. Cells in various conditions, all magnified 400 diameters. 
 
 GenXTS 2. FLEVROCOCCUS. Meneg. (1842.) 
 Cells segregated, globose (or angular from mutual pressure), 
 with a central nucleus. Single or associated in small families 
 which are either globose or cubical. Cell wall firm, often thick, 
 even, hyaline. Cell contents homogenous green, or oily red. 
 Multiplication of cells by division in alternate directions. Pro- 
 pagation by gonidia in proper cells {Sporangia) . 
 Plants aquatic, or aerial. 
 
 *Species green. 
 Fleuzococcus vulgaxis. Meneg. Nogt. 38, t. 6,/. 1. 
 Cells variable in size, simple, binate or quaternate, or as many 
 as 32 associated in families, aggregated in a crustaceous, pow- 
 dery bright-green and somewhat gelatinous (when moist) stratum. 
 
4 COCCOPHYCBJE. 
 
 Size. Cells •004--007 mm.; fam. -018 mm. [Hahh.), cells 
 •004--006 mm. (0). 
 
 Eabh. Alg. iii. 24 ; Kirch. Alg. Schl. p. 115. 
 
 Protococcus vulgaris, Kntz. Spec. p. 199. 
 
 Protococcus communis, Kutz. Tab. i., f. 3. 
 
 Pleurococcus communis, Desm. Exs. 1, 1203 ; ii. 603. 
 
 Hcematococcus vulgaris, Hass. Alg. p. 333, t. 71, f. 5. 
 
 Ghlorococcum vulgare, Grev. So. Cr., Fl. No. 262. 
 
 On the trunks of trees, moist walls, &c. Common ererywhere 
 throughout the year. 
 
 " Plant of a lively full green colour, spreading very extensively over 
 the trunks of trees, and staining the fingers on the slightest touch. Gra> 
 nules very minute, exceedingly numerous, densely aggregated, and form, 
 ing an uneven surface. They are perfectly free, semi-transparent, and 
 adhere together in an opposite manner by fours." — Greville. 
 
 Plate II. fig. I. a, natural size j b, cells X 400 diam. 
 
 Pleurococcus angulosus. (Cm-da) Meneg. NoH. t.i, f. 5. 
 
 Cells single, or 2-4, associated (64) in families, deep green, 
 nestling in greenish, rather gelatinous stratum, cell-membrane 
 thick, diaphanous. 
 
 Size. Cells •007--013 mm. (Rabh.). 
 
 Eabh. Alg. iii. 25. Kirch. Alg. Schl. p. 115. 
 
 Protococcus angulosus, Corda in Sturm PI. ii. 18. 
 
 Microcystis angulosa, Kutz. Linn«a, viii, 374. 
 
 Protococcus palustris, Kutz. Tab. i., t. 4. 
 
 On the stems and leaves of aquatic plants. 
 
 In the Kew Herbarium copy of Rabenhorst's Algae Ezsicc, No. 327, 
 under this name, only Ohroococcus tv/rgidus can be found, so that it is 
 not quoted above. 
 Plate II. f, 2. Cells magnified 400 diam. 
 
 Pleurococcus (T) mucosus. Rabh. Alg. iii. p. 26. 
 
 Cells very small, of variable size, single and 4-16, associated 
 in globose families, scattered, or aggregated in a gelatinous 
 green stratum. Cell-membrane very thin, hyaline, contents 
 homogenous, decussately divided; nucleus rounded. 
 
 Size. Cells •0023--0003 mm. {Rabh.). 
 
 Protococcus mucosus, Kutz. Tab. i., t. 4. 
 
 Hcematococcus theriacus, Hass. Alg. p. 333, t. 78, f. 9. 
 
 On the naked ground. 
 
 Dr. AUmann compares its appearance to inspissated syrup. 
 Plate II. fig. 3. Cells magnified 400 diam. 
 
 Pleurococcus Beigelii. Kiich ^ Rabh. 
 Aerial, very small, very pale greenish, aggregated in numerous 
 globose families, encircling the hair. Cell-membrane rather 
 thick, colourless, contents very finely granular, sporangia con- 
 taining 12-20 gonidia ; nucleus globose. 
 
PALMELLACE^. O 
 
 Size. Cells •006--0095 mm. (Rabh.). 
 Eab. Alg. iii. 27. 
 
 " The chignon fungus." Dr. Tilbury Fox, in " Science 
 Gossip," May 1, 1867. 
 
 On human hair used as " chignons." 
 
 Tliia organism, which ia included by Kabenhorst amongst Algae under 
 the above name, is rather a doubtful production, at least it seems to be 
 a doubtful alga. The late Dr. Tilbury Pox examined It carefully in 
 1867 with the following results : — 
 
 " If you take a hair on which the parasite exists, and hold it between 
 yourself and the light, towards the outer half you will see one or more, 
 perhaps half-a-dozen, little dark knots, the size of pin points, surround- 
 ing the shaft of the hair ; they are readily felt on drawing the hair 
 through the fingers ; they are somewhat difficult to detach. Under the 
 microscope, with a quarter-inch objective, the mass will be seen to be 
 made up of cellular bodies surrounding the hair. It will be seen that 
 the mass has the appearance of a fungus growth, of which two distinct 
 forms are here present, viz., mycelial or filamentose, and spornlar or 
 cellular. The hair is apparently healthy, and if the slide be pressed the 
 mass will break away from the iaii' on either side, bringing away with it 
 more or less of the cuticle, and leaving behind a healthy shaft. The 
 cells are seen to be of various shapes and sizes. They are from 1-4000 
 to 1-3000 of an inch, many are like the ' torula ' cells developed from 
 PeniciUum. Others are larger, undergoing division very actively. They 
 may be subdivided into two, three, or four parts, or much more freely. 
 This indicates the assumption by the parasite of an algal condition. (It 
 is this form to which the name Plewrococcus Beigelii manifestly applies.) 
 
 " In watching the mass on the hair carefully, it is evident that- a 
 number of small cells become detached from the outer orsporularform, 
 and at once move actively about. These small cells indicate an active 
 growth by subdivision, and a fruitful source of propagation. Certainly 
 this variety of fungus, so far described, is the most active growth I have 
 come across in my researches, and I have been enabled to germinate it 
 most successfully, so as to set all questions as to its nature completely 
 at rest. Placed under favourable circumstances in water, the spores 
 enlarge considerably, and the mycelial filaments increase also, but there 
 is at this time to be observed a very remarkable occurrence, though not 
 in all cases. Some of the large cells have become fiUed with smaller 
 cells, and in others, in addition to these, processes have been put forth 
 from the circumference of the walls in a radiating manner ; in other 
 cases the enlarged cells have two long cilia attached to them, by which 
 they move about rapidly, whilst a part of the hair previous to this free 
 from the fungus, has become dotted all over by minute cells similar to 
 those seen in the interior of the larger ones. 
 
 " But more than this, I have observed most distinctly large cells filled 
 with smaller cells, furnished with exceedingly delicate radiating pro- 
 cesses, and putting forth pseudopodia. It will here be seen to have 
 assumed the features of an amaeboid body. Nothing could have been 
 more distinct to myself, and those who were observing with me, than 
 this peculiar form ; and it seems to me that we have here a pretty com- 
 plete history of the life of the fungus — ^namely, the sporular sub- 
 dividing and assuming an algal form, which in turn becomes amsebi- 
 form, and furnishes ciliated cells that supply the earliest condition of 
 the fungus, scattered over the hair." Further details, with illustrations 
 are given in the memoir, of which the above ia an abstract, to which the 
 student is referred. 
 
 Plate II. f. i. Cells magnified 400 diam. 
 
b COOCOPHYCB^. 
 
 ** Species red or brownish. 
 Plenzococcus mimatus. QKuU) Nag. Mnz. Alg.p.65. 
 
 Cells very variable in size, globose, usually single, rarely 2-4 
 in a family, seated on a broadly effused red stratum, which is 
 more or less gelatinous. Cell-membrane rather thick, colour- 
 less, hyaline, contents oleaginous orange. 
 
 Size. Cells •0037--016 mm. (Eabh..), -OOSS-'OIS mm. {Kirch.). 
 
 Eabh. Alg. iii. p. 27. Eabh. Exs. 31, 368, 1777. Kirch. 
 Alg. Schl. p. 115. 
 
 On the walls of conservatories, all the year. 
 
 This is one of the species in which Brann has observed the " skinning 
 off " of the outer cell-meinbrane. 
 
 Nageli ascribes the red colour occurring in many Palmellacem, partly 
 as anonnal, partly as an abnormal phenomenon, to the formation of an 
 orange-colouied oil in the place of the chlorophyll.* Brann says that 
 probably all these have the power of retaining their life a long time in 
 the dried condition ; in the above species at least, he is qnite sure of it. 
 The brownish-red colour often acquired by Protococcus viridis may pro- 
 bably be explained in the same way.f 
 
 Plate II. fig. 5. Cells ms^nified 400 diam. 
 
 Plenzococcus zoseo-pezsicinas. Rabh. Alg. iii., 28. 
 
 Aquatic. Cells unequal, cloudy, single or biuate, tegument 
 hyaline, collected on a thin, rather gelatinous peach-rose coloured 
 stratum. 
 
 SizK. Cells -OOlS-'OOd mm. 
 
 Protococcus roeeo-persicinus, Kutz. Tab. i. t. i. 
 
 Clathrocystis roseo-perdcinus, Cohn, Beitr. iii. (1875), t. 6 
 f. 1-10. 
 
 Investing submerged aquatic plants. 
 
 This very minute species, with cells of a peach colour, is not un. 
 common about the debris of decaying plants in pools. The .cells are 
 usually agglomerated in spherical or eUiptical masses. Certainly not a 
 good Pleurococcus. 
 
 Plate II. Jig. 6. Cells magnified 400 diam. 
 
 Genus 3. GLiEOCTSTIS. Nag. (1849.) 
 
 Cells globose or oblong, either single or 2-4.-8, associated in 
 
 globose families. Common and special integuments gelatinous, 
 
 lamellose. Division in alternate directions. Propagation by 
 
 zoogonidia. 
 
 The lamellose tegument distinguishes the species of this genus from 
 Plemrooocciis. Its analogue in the PhycochromaceiB is Qloeocapsa. 
 
 * More or less green. 
 Glaeocystis ampla. Xutz. 
 Tballus gelatinous, rounded, lobed, dirty green. Cells glo- 
 bose, or rounded oblong, 2-4-6 (rarely 8), associated in fami- 
 lies ; tegument colourless, gelatinous, distinctly concentrically 
 stratose. Contents green, granular. 
 
 * Einzelliger Algae, p. 9. f " Bejuveuesoenoe," p. 213, note. 
 
PALMELLAOEiE. 7 
 
 Size. Cells •009--012 mm., fam. -O-lS-'Og mm. (Babh.). 
 Rabh. Alg. iii. p. 29. Kirch. Alg. Schl. p. 112, partly. 
 Gleocapsa ampla, Kutz. Sp. p. 216. Tab. 3, f. 3. 
 Pleurococcus superbus, Cienk. Bot. Zeit., 20 Jan., 1865, p. 
 21. Arcber Micr. Journ., 1866, p. 63. 
 Fixed to submerged plants. 
 
 Brann states that he has observed au irregalar bursting and peeling 
 oS of the outer coat of multicellular families or sometimes of isolated 
 cells surrounded by manifold coats in this species, and 6^. vesiculosa.* 
 
 Plate 111. fig. 1. Cells magnified 400 diam. 
 
 Glseocystis vesiculosa. JVa^. Einz. Alg. p. 66, t. 4 
 
 Thallus gelatinous, green ; cells small, globose, as many as 
 64, and more, associated in families ; tegument hyaline, colour- 
 less, lamellose, lamellae often breaking up ; contents green, 
 delicately granular. 
 
 Size. Cells 0045--0075 mm. ; fam. -036 mm. (JRahh.). 
 
 Rabh. Alg. iii., 29. Rabh. Exs., No. 707. 
 
 Glceocystis ampla var. vesiculosa, Kirch. Alg. Schl. p. 112. 
 
 On wood and stones in stagnant water. 
 
 In character this species resembles the last, but the cells are smaller. 
 See also Cienkowski's paper in " Botanische Zeitung " for 20 January, 
 1865, where this species is figured to the same scale as OleBoeystis 
 am/pla. 
 
 Flate III. fig. 2. Cells magnified 400 diam. 
 
 Glaeocystis zupestxis. (Lyngl.) Rahh. Alg. in., 30. 
 
 Thallus more or less expanded, dirty green, gelatinous, rather 
 firm ; cells globose, middle-size, associated in families ; tegu- 
 ment colourless, pellucid, distinctly lamellose, soon diffluent ; 
 contents green, granular ; sporangia globose, containing from 
 4-12 gonidia. 
 
 Size. Cells -OOSZ-'OOS mm. ; fam. -06 mm. ; sporang. -085 
 mm. (/?aJA.). 
 
 Rabh. Krypt. Fl. Sachs, p. 128. Rabh. Exs. 1790. Kirch. 
 Alg. Schl. p. 112. 
 
 Palmella rupestris, Lyngb. Hyd. 207, t. 69. Hook. Eng. 
 Fl. V. p. 397. 
 
 On rocks, moist walls, and damp earth. 
 
 " It occurs as a dirty yellowish gelatinous crnat often hanging down 
 in flakes from the face of the rook." — Carm. 
 
 This is not, or only in part, the Hoematoooceus rupestris, Hassall (p. 
 326, t. 82, fig. 1), which is chiefly applicable to Olfsooapsa polyderma- 
 tica, K. 
 
 Plate V III. fig. 1. Cells magnified 400 diam. a, from wet rocks ; 
 6, from damp earth. 
 
 * See Braun, "Eejuvenesoenoe," Eay Society, p. 182. 
 
8 COCCOPHYCE^. 
 
 Glaeocystis botzyoides. Kta. Phy. Gen. p. 173. 
 
 Thallus gelatinous, soft, sticky, green ; cells minute, globose 
 and oblong, associated in small families ; tegument colourless, 
 indistinctly lamellose, contents green. 
 
 Size. Cells ■002--004 mm. ; families •01--018 mm. 
 
 Glmocapsa hoti-yoides, Kutz. Tab. 1, t. 20. 
 
 On wood, submerged or constantly wet. 
 
 Plate III. fig. 3. Cells magnified 400 diam. 
 
 ** Flesh-coloured, becoming reddish. 
 
 Glaeocystis Fazoliniana. {Meneg. Nost. 1. 10,/. 2.) 
 
 Thallus criistaceous, cartilagineous (horny when dry), about a 
 line thick, flesh colour; cells small, spherical, 2-4-8 associated 
 in families ; tegument very broad, distinctly concentrically 
 lamellose ; contents becoming yellowish, granulose. 
 
 Size. Cells •0037--005 mm. ; families -24 mm. (BaW.). 
 
 Eabh. Alg. iii. 30. 
 
 Microcystis Paroliniana, Meneg. Nost. p. 78. 
 
 Olaeocapsa Paroliniana, Kutz. Tab. i. 36, f. 5. 
 
 On rocks constantly wet. 
 
 Collected some years ago in Kent by Eev. M. J. Berkeley, and usually 
 f ODnd near the sea. 
 
 Plate III. Jig. 5. Cells magnified 400 diam. 
 
 Glsocystis adnata. CBv4s.) Nag. 
 
 Thallus broadly expanded, gelatinous, firm, yellow-brown ; 
 cells globose, or oblong; contents brownish-green or brown, 
 granular; tegument colourless, pellucid, lamellose. 
 
 Size. Cells •008--013 mm. {Rabh.). 
 
 Eabh. Alg. iii. 31. 
 
 Tremella adnata, Huds. Fl. Ang. p. 565. 
 
 FalmeUa adnata, Lyngb. Hydro, p. 205, t. 69. Berk. Glean, 
 p. 40, t. 15, f. 2. 
 
 Microcystis adnata, Meneg. Nost. p. 85. 
 
 " Forming a thin yellow-brown, suborbionlar, depressed stratum on 
 chalk cliffs, about high-water mark. The individual plants, which are 
 from 1 -6 lines diam., are but very little thicker in the centre than at the 
 margin. The surface is rugulose and shining, substance firm, between 
 gelatinous and coriaceous. In age the plant gradually becomes more 
 tawny, but at all times under the microscope presents a pale cchraceous 
 jelly filled with darker granules. Under a moderate magnifier the 
 granules appear globose, but under a lens with l-25th in. focus pellucid, 
 globose, colourless vesicles are seen to contain the darker granules, and 
 these are found to be elliptic. Sometimes the vesicles contain a little 
 tawny colouring matter, as though the sporules were broken down ; and 
 frequently the sporules burst through the coat of the vesicle in which 
 they are contained, and lie free on the general mass." — Berkeley. 
 
 Plate III. jig. 4. a, natural size ; b, cells magnified 400 diameters. 
 
PALMBLLACE^. V 
 
 Genus 4. UROCOCCVS. ffass. (1845.) 
 Cells large, globose, or oblong, reddish or blood-red ; tegu- 
 ment thick, gelatinous, concentrically lamellose ; stem thick, 
 gelatinous, often ringed or annulate. 
 
 All the specie9 in this genua are rare, and with one exception confined 
 to Britain. We are, therefore, compelled to reprodaoe figures already 
 published, without measurements or information beyond the original 
 desoriptions. 
 
 The peculiar structure of the pedicellate cells is thus described by 
 Braun: — " The large globular brownish-red or blood-red cells throw off 
 coloarless layers of cell membrane, which appear to be separated by 
 intermediate layers of softer jelly, whence arises a distinctly concentric 
 structure of the envelope. But the enveloping layers of Urococcits do 
 not retain their original form and integrity ; not increasing themselves 
 in size, they are pushed off on the upper side by constantly succeeding 
 inner coats, being at first merely attenuated at one side, but subse- 
 quently, as it seemed to me, actually broken through. Since this emer. 
 gence from the old coats is always repeated on the same side, a mem- 
 branous-gelatinous peduncle is produced formed of cups fitted one into 
 another, so as to give au annularly streaked, apparently shortly articu- 
 lated aspect. The red cell, which occupies the summit of this peduncle, 
 sometimes divides, and this of course produces a subsequent dichotomy 
 of the peduncle. If the periods of the formation of the separate 
 enveloping layers were known, the age of the little plant, whose 
 history is preserved in the gelatinous peduncle, might be determined by 
 the number of rings." — Iiejuvenescence,p. 179. 
 
 * Stem annulate. 
 
 Uzococcus HookerianuB. Hass. Alg.t. 80,/. i. 
 
 Cells globose, or elliptic, variable in size, blood-red, granular, 
 stem more or less elongated, often divided, densely ringed. 
 
 SizB. Cells •013--06 mm. (liabh.). 
 
 Eabh. Alg. iii. 31. 
 
 Hcematococcus Hooheriana, Berk. & Hass. in Hass. Alg. p. 
 325, t. 80, f. 4. 
 
 On chalk cliff, &c. 
 
 Plate IV. fig. 1. a, cells considerably magnified, after Hassall ; b, 
 cells further magnified, after Kabenhorst. 
 
 Vzococcus insignis. B.au. Alg.t. SO,f.G,a. h. 
 Cells large, globose, blood-red; stem abbreviated, remotely 
 annulated. 
 
 Eabh. Alg. iii. p. 31. 
 
 Hcematococcus insignis, Hass. Alg. p. 324. 
 
 " This very fine species I have never met with in any considerable 
 quantity. Scattered isolated globules I have frequently met with, and 
 these occasionally attached to a closely corrugated or ringed mucous 
 appendage. Each globule is usually surrounded by a single vesicle or 
 ring ; in some globules, however, there are as many as four or five en- 
 closing vesicles." — Hassall. 
 
 Plate IV.fig, 2. a, b, cells considerably magnified, after Hassall. 
 
10 COCCOPHYCE^. 
 
 ** Stem without rings. 
 Uzococcus Allmanni. Bass. t. 80, /. 3. 
 Cells elliptical, blood- red; stem short, rather club-shaped, 
 colourless, smooth. 
 Eabh. Alg. iii. p. 322. 
 Hcematococcus Allmanni, Hass. Alg. p. 322. 
 
 In springs at Knares borough. 
 
 Plate IV. fig. S. a, cells considerably magnified, after Hassall; b, 
 cells farther magnified. 
 
 Vzococcus cryptophilus. Uass. t. 80, f. 1. 
 
 Cells small, oval, rarely globose ; tegument very large, con- 
 fluent with the short ringless stem. 
 
 Eabh. Alg. iii. p. 32. 
 
 Hcematococcus cryptophila, Hass. Alg. p. 324. 
 
 Hcematococcus sanguineus, Harv. Man. p. 181. 
 
 Palmella cryptophila, Carm. in litt. 
 
 On stalactites lining a cavern in a quartz rock. 
 
 "Forms wide patches externally of a brick -red colour, but within 
 whitish, breaking np easily Into the numerous separate portions of 
 which each mass is formed. The colour resides alone in the granules ; 
 these terminate the superior extremity of the mucous prolongations, 
 which are colourless, and arranged almost entirely side by side. The 
 granules or cells are several times smaller than in U. Allmanni." — 
 Hassall. 
 
 Plate IV. fig. 4. a, cells considerably magnified, after Hassall ; b, 
 cells further magnified. 
 
 Genus 5. SCHIZOCKI.AIHyS. ^r. (1849.) 
 
 Cells globose (or ovate), either single, or 2-4 associated in 
 
 families ; tegument lamellose, as age advances dividing regularly 
 
 in 2-4 equal parts, some time adhering by means of a hyaline 
 
 colourless mucous. Division in one or two directions. Zoo- 
 
 gonidia produced by a repeated division of the cell contents. 
 
 At present represented in Europe by a single species. 
 
 " The globular cells of this little Alga produce a hyaline cell-mem- 
 brane, which becomes removed to some distance from the green body 
 of the cell by subsequent secretion of fluidish jelly ; soon, however 
 (probably from endosmose), becoming unable to withstand the expan- 
 sion of the jelly, it splits in the direction of an equatorial circle, by a 
 clean line, into two similar halves, or if the dehiscence takes place by 
 two circular lines, cutting at right angles, into four similar pieces. 
 This splitting and peeling of the membrane either coincides with a 
 division of the internal cell-mass, or it occurs without any such division. 
 By frequent repetition of this process the cell gradually becomes 
 surrounded by an accumulation of old fragments of the membranous 
 shell, which are held together by the extremely transparent jelly set 
 free. The division of the cell may be either a simple halving, in which 
 case each part is immediately clothed again with a hyaline cell-mem- 
 brane, or double, through the cells produced by the first division sepa- 
 
PALMELLACE^. 11 
 
 rating immediately into two cells, withont previously acquiring a coat 
 of cell-membrane, and therefore without skinning." — Braun Rejuvenes- 
 cence, p. 181. 
 
 Schizochlamys gelatinosa. Br.inKiiiz. Sp. ^.891. 
 
 Cells globose ; contents green, granulose. 
 Size. •01--0135 mm. {Rahh.). 
 
 Kutz. Tab. vol. vi. t. 70. Braun Rejuvenescence t. 2, f. 43- 
 50. Rabh. Alg. iii. 32. Rabh. Exs. No. 103. 
 
 In peaty swamps, moor pools, and boggy ditches. 
 
 Plate III. Jig. 6. Cells magnified 400 diam. 
 
 Genus 6. FALIfflELLA. hyngl). (1819.) 
 
 Cells globose, oval, or oblong, surrounded with a more or less 
 thick integument, generally very soon confluent into a firm or 
 soft jelly. Thallus shapeless. Division of the cells alternately 
 in all directions. 
 
 * Mostly green. 
 
 Falmella mucosa. Kutz. Phyc. Gen. p. 172. 
 
 Thallus expanded, gelatinous, deformed, olivaceous-green ; 
 cells large, nearly equal, pale green, delicately granular ; tegu- 
 ment very thin, soon diffluent. 
 
 Size. Cells -015 mm. {Rabh.), ■007--014 mm. (Kirch.). 
 
 Rabh. Alg. iii. 33. Kirch. Alg. Schl. p. 110. 
 
 Merettia mucosa, Trevis. Alg. p. 46. 
 
 On stones in streams. 
 Plate V. Jig. 1. Portion of thallus with cells magnified 400 diam. 
 
 Falmella hyalina. Breh. Alg. Fal. p. 39. 
 
 Thallus gelatinous, irregularly expanded, green ; cells very 
 minute, crowded ; tegument almost homogenous with the gela- 
 tinous thallus, very soon dif&uent. 
 
 Size. Cells -OOOS-'OOl mm. (Rabh.), -OOOTS-'OOl mm. 
 (Kirch.). 
 
 Rabh. Alg. iii. 33. Rabh. Exs. 1525. Kirch. Alg. Schl. 
 p. 110. 
 
 Coccochloris hyalina, Meneg. Nost. p. 66. 
 
 In stagnant water, and bogs. 
 
 The species called Coccochloris hyalina by Hassall (p. 315) is ffomalo- 
 coccus Hassallii, Kutz., one of the Phycochromophyceie, and not the 
 present. Perhaps the two may have been mixed up. 
 
 Plate V.Jig. 3. o,, part of thallus, X 400 j i, portion X 800 diam. 
 
12 COCCOPHYCE^. 
 
 Falmella Mooreana. Harv. Man. p. 178. 
 
 Thallns irregularly globose, tnberculate, dark green, gelati- 
 nous, firm. Cells nearly equal, pale green. 
 
 Size. Cells -008 X 005 mm. 
 
 Eabh. Alg. iii. p. 34. 
 
 Coccochloris Mooreana, Hass. Alg. 316, t. 78, f. 1. 
 
 In bogs and stagnant water. 
 
 " The fronds are of an irregalar globose form, about an inch in 
 diameter, tuberculated, and inclining to become hollow in the centre 
 when old, at which time it floats on the surface ; the colour is dark- 
 green and the substance firm, resembling that of an animal's liver." — 
 Moore. 
 
 We found this species floating freely in a pond in Sntton Park, Bir- 
 mingham. In this condition it has just the appearance and texture of a 
 Nostoc. Is it distinct from Aphamothece prasina ? 
 
 Plate V. fig, 4. a, plant natural size ; 6, portion X 400 diam. 
 
 ** Reddish or orange. 
 
 Falmella miniata, var. aequalis. Nag. JEinz. Alg. t. 4, D. 2. 
 
 Thallus expanded, soft, amorphous, brick-red ; cells nearly 
 equal, tegument somewhat tbick, colourless, hyaline, indistinctly 
 striate ; contents orange, sometimes greenish. 
 
 Size. Cells ■012--014 mm. 
 
 Eabh. Alg. iii. 34. Eabh. Exs. No. 1778. 
 
 Sorospora grumosa, Hass. Alg. p. 310, t. 80, f. 7. ? 
 
 On wet rocks, moist ground, &c. 
 
 We are of opinion that this is the Sorospora grumosa of Hassall. The 
 typical form of Falmella mimiata has very minute cells, not exceeding 
 "0035-00+ mm., but this variety, if it be not a distinct species, has cells 
 nearly four times as large. 
 
 Plate V.fig. 2. Portion of thallus, magnified 400 diam, 
 
 Falmella piodigioaa. Mont. Comptes Bend. 1852, 119. 
 
 Thallus more or less expanded, blood- red, as age advances 
 moist, or sometimes dripping ; cells very minute, globose, 
 crowded. 
 
 Size. Cells •00075--001 mm. (Rabh.). 
 
 Eabh. Alg. iii. 34. Stephens, Ann. Nat. Hist. 2 Ser. (1853), 
 xii. 409. Berk, in Gard. Chron. 1853, p. 515. 
 
 Monas prodigiosa, Ehrb. Monat. Berl. 1848. 
 
 Zoogalactina tmetropha, Sette. Mem. Ven. 1824. 
 
 On rice, bread, potatoes, &c. 
 
 In the time of Ehrenberg this was considered a minute animal, and 
 was included amongst Monads. The blood-red spots which it forms on 
 bread, rice, potatoes, and other mealy substances, caused great alarm in 
 more superstitious times. Until very recently opinions were by no 
 means settled on this subject. The Rev. M. J. Berkeley held it to be a 
 condition of fungoid life, and in his "Introduction"* he says, " Pal- 
 niella prodigiosa, from its peculiar habit, seems rather to indicate 
 aifinity with fungi. The rapidity with which it spreads over meat, 
 
 * " Introduction to Cryptogamic Botany," p. lit. 
 
PALMBLLACE^. 13 
 
 boiled vegetables, or even decaying Agarics, is quite astonishing, making 
 them appear as if spotted with arterial blood ; and what increases the 
 illusion is, that there are little detached specks, exactly as if they had 
 been sqnirted in jets from a small artery. The particles of which the 
 substance is composed have an active molecular motion, but the mor- 
 phosis of the production has not yet been properly observed, and till 
 that is the case it will be impossible to assign its place rightly in the 
 vegetable world. Its resemblance to the gelatinous specks which occur 
 on mouldy paste, or raw meat in an incipient state of decomposition, 
 satisfy me that it is not properly an Alga." Mr. H. O. Stephens, on 
 the other hand, contends that it is an Algoid production. After nar- 
 rating its history (see "Ann. Nat. Hist.," 1853, p. 409), he says — "I 
 observed at table the under surface of a half-round of boiled salt beef, 
 cooked the day before, to be specked with several bright carmine- 
 coloured spots, as if the dish in which the meat was placed had con- 
 tained minute portions of red currant jelly. On examination the next 
 day, the spots had spread into patches of a vivid carmine-red stratum of 
 two or more inches in length. 
 
 " With a -simple lens the plant appears to consist of a gelatinous sub- 
 stratum of a paler red, bearing an upper layer of a vivid red hue, hav- 
 ing an uneven or papillate surface. The microscope shows this stratum 
 to consist of generally globose cells immersed in or connected by muci- 
 laginous or gelatinous matter. The cells vary in size, and contain red 
 endochrome. As far as I can observe they consist of a single oell- 
 membrane, and contain a nucleus. Treated with sulpho-iodine, they 
 become blue. In my judgment this plant is a Pahnella closely allied to 
 P. cruenta, but certainly distinct, the cells or granules of the latter 
 differing from it not only in their colour but size." The memoir also 
 contains observations on the great vitality of this species, and other 
 subjects connected therewith, to which the student is referred. 
 
 Plate V. fig. 5. a, part of thallus, magnified 400 diam. j 6, portion 
 magnified 800 diam. 
 
 Genus 7. PORPHYRlDIUffll. Niig. (1849.) 
 Thallus between gelatinous and membranaceous, somewhat 
 incrusting, long and broadly expanded, composed of globose or 
 many-sided cells. Multiplication of the cells by alternate di- 
 vision in all directions. Propagation unknown. 
 
 This genus is placed by some authors in Porphyracece, near the genus 
 Bangia, in the Aeas Rlwdophycrce (see Eabh. Alg. iii. 397), but we prefer 
 to retain it near the old genus Palmella, in which it was previously m- 
 cluded, and to which it seems to be most naturally allied. 
 
 Porphyridium cruentum. Nag. EA,nz. Alg. t. 4 H. 
 Thallus dark purplish-red, gelatinous ; cells angular or 
 
 rounded. ^^, , ^ 
 
 Size -OOT-'Ol mm. (Eabh.), -OOeS-'OOg mm. (Kirch.). 
 
 Kirch. Alg. Schl. p. 111. Eabh. Alg. iii. 397. 
 
 Palmella cruenta, Ag. Syst. p. 15. Rabh. Exs. No. 14 and 
 1071. Hass. Alg. p. 308, t. 80, f. 5. 
 
 Tremella cruenta, Eng. Bot. t. 1800. Grev. Sc. Crypt. Fl. 
 pi. 205. 
 
 On the naked ground, moist walls, &c. Common throughout 
 Europe. 
 
14: COCCOPHYCE^. 
 
 The red spols are at first rounded, then irregular, soon confluent, and 
 form an expanded crust, like coagulated blood of a deep purple colour. 
 Plate Y.Jig. 6. a, plant natural size; 6, cells magnified 400 diam. 
 
 Genus 8. BOTRTDINA. Brel. (1839.) 
 
 Cells oblong or rounded, involved in a very thick, gelatinous, 
 partially diffluent integument, in large families, which are often 
 very numerous, enclosed in a mother cell which constitutes a 
 subglobose thallus. 
 
 Only one species in this genus. 
 
 Botxydina vnlgsuris. Breb. iit Hass. Alg. 320. 
 
 Thallus minute, rarely larger than the head of a pin, glo- 
 bose, green. 
 
 Size. Thallus from 1 -500th to 1-lOth mm. ; cells •002--004 
 mm. 
 
 Meneg. Nost. p. 98, t. 13, f. 2. Rabh. Alg. iii. 37. Eabh. 
 Exs. No. 388. Hass. Alg. p. 320, t. 81, f. 2. Kirch. Alg. 
 Schl. p. 111. 
 
 On moist ground, trunks, moss, &c. 
 
 " The fronds of various sizes, rarely surpassing the head of a pin, of 
 a subsphserical form, aggregated in considerable quantity, cover the 
 stems of mosses with a pulverulent blackish-green stratum, which 
 Agardh first well delineated. The grannies, in the beginning solitary, 
 here and there affixed, subsphserical, or slightly angular, scarcely equal 
 in their greatest diameter l-500th mm. ; gradually they increase in size, 
 and when they have arrived at the 1 -200th mm. they manifest an in- 
 ternal granular substance ; at a later period having acquired a form 
 exactly spherical, the internal substance is seen aggregated or collected 
 into the centre, and the granules surrounded by a pellncid margin. 
 Again, they increase in size, and the interior grannies are seen con- 
 verted into vesicles filled with lesser granules. These vesicles in- 
 creased in number and magnitude, tho greatest dimensions of the frond 
 being attained, occupy its entire substance, and at length the diapha- 
 nous margin disappears. The whole frond is then constituted of vesi- 
 cles closely heaped together, and enclosing granules in the centre. The 
 primitive membrane, enclosing in its midst the interwoven or cellular 
 structure, is so closely united with the peripheral stratum of vesicles, 
 that it can in no way be separated from it. The last development hav- 
 ing been accomplished, the peripheral stratum of vesicles altogether 
 loosens its granules ; whether these disappear by absorption or escape 
 outwardly, I have never been able to perceive. In this manner the 
 frond again obtains a diaphanous margin, but different from that with 
 which, in the beginning, it was surrounded." — Meneghini. 
 
 Plate XI. fig, 3. a, thallus magnified 400; i, cells further magnified. 
 
 GENUS 9. FALMODICTTON. Ktz. (1845.) 
 Cells oval or globose, with a very thick gelatinous integu- 
 ment, united into a filiform thallus, which is connate or anasto- 
 moses in various ways. Cell division simple or double (de- 
 cussate). Propagation by zoogonidia from the ultimate gene- 
 ration of cells. 
 
PALMKLLAOK^. 15 
 
 Palmodictyon viride. Kutz.Tab.Phy.l. t. 81,/. 1. 
 
 Thallus mucous, irregularly reticulate, about tlie thickness 
 of a hair, greenish ; cells biserial, with a very thick homoge- 
 nous tegument. 
 
 Size. Cells without tegument, -OOTS-'OOO mm., with the 
 tegument ■025--04 mm. {Rabh.). 
 
 Eabh. Alg. iii. 37. Kutz. Phy. Germ. p. 155. 
 
 In ditches, canals, &c., attached to stones, twigs, &c. 
 
 Eeoently found by Mr. B. Parfitt near Exeter, of which he gives the 
 following acconut ; — " The plant, where it has safficient room to develops 
 itself, spreads over the bottom, in water about six inches deep ; beyond 
 this it comes in contact with Ulodes canadensisi over which it creeps, and 
 extends its growth from branch to branch into deeper water. In this 
 extension it has first the appearance of a Conferva, which I at first took 
 it to be J but the moment I touched it, after taking some from the 
 water, I found from the soft slimy feel that if a Conferva it was new to 
 me, and the microscope soon revealed the true character. When the 
 plant gi'ows on the bottom it shows one continuous green membrane, 
 stretched tight over the bottom, but when it comes 'in contact with other 
 plants it throws out filaments, the thickness of which is difficult to make 
 out on account of their adhesive nature j for wherever they touch it is 
 matter of impossibility to separate them. The membrane forming the 
 filaments is structureless, but the sphserical cells, which form more or 
 less moniliform threads, sometimes running in parallel lines, at other 
 times forming an irregular net-work on the inside of the filaments. 
 These cells sometimes divide into two portions, at others into four, and 
 in most of the mature cells may be observed four cellules." — Qrevillea, 
 iii., p. 29. 
 
 Plate VIII. fig. 2. tt, portion magnified 200 diam. j 6, fragment 
 magnified 400 diam. 
 
 Falmodictyon xufescens. Kidz Spec. 234. 
 
 Is usually referred here on the faith of the remark by Kutzing, that it 
 was found at Aberdeen by Dr. Dickie. Upon enquiry of Dr. Dickie we 
 learn that he knows nothing of the species. He says, " PaVmodictyon 
 rujescens is unknown to me, many years have passed since I corres- 
 ponded with Lenormand, and I do not remember receiving any note 
 from him regarding it. Kutzing (Spec. 234) is responsible for the name. 
 I cannot find in my collection anything so named, neither do I re- 
 member where the so-called material was collected." Under these cir- 
 cumstances it is useless repeating the name in connection with British 
 Algae. 
 
 Gbnus 10. TETRASPORA. Link. (1810) 
 
 Thallus gelatinous, membranous, or submembranous, in the 
 beginning a short sac, afterward expanded; cells globose or 
 angular, more or less distant, but associated in a single stratum 
 into large families. Tegument thick, very rapidly diffluent into 
 a homogenous mucous. Division in two directions in the same 
 plane. 
 
16 
 
 COCCOPHTCE^. 
 
 Tetraspora bullosa. Ag. Sp. Alg. p. 414. 
 
 Thallus membranaceous, saccate, obovate, sinuate, buUose, 
 an inch to a palm long, dark green, more or less verrncose ; 
 cells nearly sphaerical (after division hemisphEerical or angular), 
 geminate, or quatemate, crowded, granular. 
 
 Size. Cells before division ■008-'012 mm., after division 
 ■0058--0075 mm. {Babh.). 
 
 Eabh. Alg. iii. 39. Rabh. Exs. No. 115, 1233. Kircb. 
 Alg. Scbl. p. 108. 
 
 Monotrema bullosum, Thur. Mem. Cherb. 1854. 
 
 Tetraspora minima, Desv. Flor. Aug. p. 17. 
 
 Ulva bullosa, Roth. Cat. iii. 320. Hook. Brit. Fl. ii. 312. 
 Harv. Man. p. 171. Hass. Alg. t. 78, f. 13. Dickie Bot. 
 Guide, p. 306. Eng. Bot. ed. 2, t. 2405. 
 
 Stagnant pools and ditches of fresh water. 
 Plate VI. Jig. 1. a, natnial size ; b, fragment mag. 400 diam. 
 Tetjraspoza gelatinosa. (^Vaiich.') 
 
 Thallus vesiculose, ovate-clavate, or obovate, gelatinous, with 
 age unequally expanded, irregularly torn, pallid and sometimes 
 dirty-green, often incrusted with lime ; cells of variable size, 
 globose, either single or geminate, and scattered or quatemate, 
 or geminate, and somewhat crowded ; contents green and 
 granular. 
 
 Size. Cells •003--014 mm. {Rabh.). 
 
 Rabh. Alg. iii. 40. Hook. Br. Flor. ii. 313. Mackay Flor. 
 Hiber. p. 244. Hass. Alg. p. 301. Kirch. Alg. Schl. p. 109. 
 
 Viva gelatinosa, Vauch. Hist. p. 244, t. 17, f. 2. 
 
 Rivularia tubulosa, DC. Fl. Fr. ii. p. 5. 
 
 In pools and ditches. 
 
 Plate VI. Jig. 2. a, natural size ; b, fragment mag. 400 diam. 
 Tetraspora Inbrica. {Moth.') 
 
 Thallus elongated, tubular, erect, an inch to a palm long, 1-4 
 lines thick, splitting, undulate, sinuous, sticky, between gela- 
 tinous and membrauaceous, yellow-green ; cells globose, or 
 ratlier angular, of medium size, green ; tegument very thin. 
 
 Size. Cells •008--01 mm. {Rabh.). 
 
 Rabh. Alg. iii. 41. Rabh. Exs. No. 51. Dickie Bot. Guide, 
 p. 306. Eng. Bot. ed. 2, t. 2407. Hass. Alg. p. 300, t. 78, f. 
 10. Kirch. Alg. Schl. p. 109. 
 
 Tetrasporella lubrica, Gaill. Desm. Ex. i. 655. 
 
 Ulva lubrica, Roth. Cat. i. 204. 
 
 Conferva lubrica, Roth. Cat. iii. 168. 
 
 Plate VI. Jig. 3. a, natural size ; b, fragment mag. 400 diam. 
 Tetraspora flava. Hass. Alg. t. 1&,f. 11. 
 
 Thallus yellow when dry, cellules small, quatemate. 
 
 Rabh. Alg. iii. p. 42. 
 
 In rocky rivulets. 
 
PALMELLACEiE. 17 
 
 " This species, at all events, would appear to be distinct, the cells 
 being two to three times smaller than those of T. lubrica and T. gela- 
 tinosa." — Hassall. 
 
 This is a doabtfal species, which no one bnt Hassall appears to have 
 seen. 
 
 Plate FX ^. 4. Fragment magnified, after Hassall. 
 
 Genus 11. BOTB.YOCOCCVS. Kutz. (1849.) 
 Thallus botryoid (or like a bunch of grapes), irregularly 
 lobed, mucous, involved in a thin parent membrane (?). Cells 
 ovoid or elliptic, united in families, which are densely packed 
 within a thin diffluent tegument. 
 Represented in Europe by a single species. 
 
 Botzyococcus Bzaunii. Kidz. sp. S92. 
 
 Small, free swimming, green, at length becoming pallid or 
 reddish-brown. 
 
 Size. Cells ■01--0125 mm. {Rabh). 
 
 Eabh. Alg. iii. 43. Fres. in Abh. Senk. t. ii. f. 27-33. 
 Archer Micr. Journ., 1870, p. 88. Kirch. Alg. Schl. p. 111. 
 
 In moor pools. 
 
 Specimens were fonnd by Dr. Moore floating on the snrface of Longh 
 Bray in long sheets of some yards in length. Mr. Archer remarked 
 npon these " that this was not an nncommon alga in moor pools, some- 
 times coating submerged sedges, and the like, with a greyish green 
 stratam, sometimes, however, suspended in the water in streaks, and 
 often isolated. It passes through a red condition. More than once, 
 when a single group or family of this alga, from gatherings kept for 
 some time in the house, had turned up under a low power of the 
 microscope, he had been to some extent deceived by the way in which it 
 resembles some radiolarian rhizopod, strange as it may seem. The 
 mucous matrix containing the families of cells seems not unfrequently 
 to give ofE rather long, filiform prolongations, which stand out more or 
 less radiantly, looking not unlike pseudopodia and these are undoubted 
 rhizopoda containing chlorophyll. It might, indeed, be a good example 
 of two objects with no affinity in any respect to each other, still super- 
 ficially simulating one another." — Micro. Journ , 1870, p. 88. 
 
 Plate VII. Jig. 2. a, family group ; b, single family ; c, undergoing 
 segmentation ; d, free mature cells. AH magnified 400 diameters. 
 
 Genus 12. APIOCYSTIS. Nag. (1849.) 
 Thallus small, vesicular, fixed by a stem-like base. Cells 
 globose, scattered, or sometimes 8 disposed in a circle ; contents 
 homogenous, or delicately granulosa, with a distinct colourless 
 vacuole ; tegument thick, dissolving into a homogenous gela- 
 tine, cells dividing alternately in all directions. Propagation by 
 mobile gonidia, which are globose, and furnished with a pair of 
 vibratile cilia. 
 
 This genus consists of a single species, unless the variety linearis of 
 Nageli is entitled to rank as specifically distinct. 
 
 D 
 
18 COCCOPHYCEJE. 
 
 Apiocystia Bxauniana. Nag. Einz. Alg. p. 69. 
 
 Thallus pear-shaped, pallid green, the cavity filled up by 
 gelatinous matter, in which are imbedded the gonidia, at first 
 few, increasing in number with age, as far as 1600. 
 
 Size. Frond -Oi-'l mm. high, gonidia '012 mm. diam., 
 cells •0075--011 mm. (Rabh.). 
 
 Rabh. Alg. iii. 43. Fresen. Beitr. p. 237, t. ii. f. 1-20. 
 Henfrey in Micro. Journ., 1856, p. 52, t. 4, f. 26-27. 
 
 Fresh water ditches, &c. 
 
 Professor Henfrey found this plant in January, in a jar of water con- 
 taining aqnatic plants brought from Wimbledon Common six months 
 previously. The development, as recorded by Nageli, is detailed in the 
 article quoted above. 
 
 " The young • swarm cells ' (zoospores) attach themselves by their 
 ciliated point (especially to Cladophora Jracta), and become invested 
 with a club-shaped, enveloping membrane. The first division of the 
 green body then takes place in the direction of the axis of the vesicular 
 envelope, and is repeated alternately in each direction of space. During 
 this the vesicle in which the cells (gonidia) lie, continually expands, and 
 generally becomes very evidently pedunculated. Young vesicles 
 contain a regular number of cells, namely, 2, 4, 8, 16, 32, &c., but the 
 number afterwards becomes indefinite ; in largish vesicles, 1-50" 
 (■5 mm.) long and 1-120" ('22 mm.) diam. 1 have counted about 300 ; 
 in the largest, about 1-25" ('1 mm.) long and 1-50'' ("5 mm.) thick, some 
 1,600 cells. 
 
 " The cells (gonidia) are at first uniformly distributed over the whole 
 cavity of the vesicle. Subsequently they generally become collected on 
 the internal surface of the wall of the vesicle, where they lie in one or 
 more strata. But the cell division always takes place in all directions 
 of space, the cells situated internally advancing outwards towards the 
 periphery. In old vesicles the cells are sometimes arranged in rings 
 of eight upon the wall. When the family of cells is mature for 
 ' swarming,' which may occur at very different sizes and with very 
 different numbers of gonidia, the cells begin to move, at first slowly, 
 from their places, and then gradually to circulate more rapidly in and 
 out about each other ; the vesicle bursts, and the gonidia emerge by the 
 orifice which is formed. Sometimes the swarming is preceded by the 
 state in which the cells are arranged in parietal rings. 
 
 " The cells secrete an abundant gelatinous coating, which becomes 
 softened within the vesicle, and confluent into a structureless jelly. The 
 vesicle sometimes appears merely as the boundary line of the jelly ; in 
 general, however, it may be distinguished as a distinct wall composed of 
 denser gelatinous substance, the internal outline of which is always 
 distinct and sharp, while the outer is frequently indistinct, and partly 
 dissolved." — Ndgeli. 
 
 Plate VII. fig. 1. a, young frond ; b and c, older fronds X 100 
 diam. ; d, frond with cells undergoing segmentation X 200; e, part of 
 frond with mature gonidia X 400 ; f, free gonidia ; g, ciliated gonidia or 
 zoospores X 400 diam. 
 
 Inoderma lamellosum, Eutz., has been said to have occurred in 
 Britain, but we have not been able to satisfy ourselves of its occur- 
 rence. 
 
PALMELLAOB^. 19 
 
 Genus 13. RHAFHIDIUSI. Kufz. (1845.) 
 Cells fusiform, or cylindrical, generally very gradually cuspi- 
 date or acuminate at the ends, rarely obtuse, straight or 
 variously curved, single, geminate, or fasciculately aggregate, 
 decussate in the centre, or radiately conjoined, rarely two 
 laterally united at the end, other cells free. Tegument thin, 
 smooth. Contents green, very finely granular, furnished with a 
 central, or rarely lateral, transparent vacuole. Division of the 
 cells only in one direction. 
 
 Rhaphidium aciculaze. Brawn. JRabh. Exs. 442. 
 
 Yery slender, 15-20 times as long as broad, yellow-green, 
 often single, acicular, acutely cuspidate at each end, straight, or 
 slightly curved or somewhat lunate. 
 
 Ankistrodesmus acutissimus, Archer in Micr. Journ., 1862, t. 
 xii. f. 44-66. 
 
 Closterium Griffithii, Berk. Ann. Nat. Hist. xiii. 256, t. 14, 
 f. 2. 
 
 Rhaphidium polymorphum var. y aciculare, Rabh. Alg. iii. 45. 
 
 In pools. 
 
 " Cells very minute, 20-25 times longer than broad, fusiform, very 
 slender, straight, very acutely acicular, solitary or forming fasciculi of 
 2-4 cells ; endoohrome light-green, mostly with a minute parietal semi, 
 circular or rounded pale body or space placed near the middle of the 
 cell, otherwise usually appearing homogenous, sometimes slightly 
 granular." It agrees with M. faloatum in its very slender and acute 
 cells, but it differs from it by its straight, not arcuate cells, by its fusi- 
 form more quickly attenuated cells, by its more intensely acute extremi- 
 ties, and by the constituent cells of an old fasciculus being much fewer 
 in number. — Archer. 
 
 Plate VIII. fig. 3. Cells magnified 4O0 diam. 
 
 Rhaphidium falcatum. (Corda.) 
 
 Fusiform, slender, acutely cuspidate at each extremity, 
 curved, or semi-lunar, 4-16 congregated in fascicles. 
 
 Micrasterias falcata, Corda Aim. Carls. 1835, p. 121, t. 2, 
 f. 29. 
 
 Staurastrum falcatum, Ehr. Weigm. Arch. 1836, p. 185. 
 
 Closterium falcatum, Meneg. Linnsea, 1840, p. 233. 
 
 Ankistrodesmus gregarius, Breb. in litt. 
 
 Ankistrodesmus faleatus, Ealfs Desm. t. 34, f. 3. 
 
 Rhaphidium polymorphum, var. c. falcatum, Rabh. Alg. iii, 45. 
 
 In pools. 
 
 It is a very common -plant in ponds, &0., and resembles a minute 
 young Closterium, except that although some individuals may be soli- 
 tary, others will be seen in the same gathering collected in the charac- 
 teristic fascicles. 
 
 Plate VIII. fig. 4. a, families magnified 400 ; b, magnified 800 diam. 
 
20 COOCOPHYCB^. 
 
 Rhaphidittm duplex. Kwtz. Phyc. Germ, p. 144. 
 
 Fusiform, slender, slightly sigmoid, single, or 2, 3, or 4 
 laterally connected at the poles, otherwise free. 
 
 Rhaphidium triplex, Rabh. Krypt. Fl. Sax., p. 134. 
 
 Scenedesmus duplex, Ralfs Desm. 193, t. 34, f. 17. 
 
 Rhaphidium polymorphum var. d. sigmoideum, Rabh. Alg. iii. 
 p. 45. 
 
 In pools (apparently rare). 
 
 " Cells linear-lanceolate ; extremitiea tapering to a fine point and 
 carved in opposite directions. The cells closely united, frequently the 
 frond, consists of only a single pair of cells so connected, bnt sometimes 
 of two or even three of these pairs, which, however, are remote from 
 each other, in this case ; as the connecting macous is colonrless, they 
 look like distinct plants, and their relation can be detected only by 
 moving the frond. If kept in water for a few days, the cells separate 
 from each other.'' — Ralfs. 
 
 This description is scarcely accurate, as each cell is a distinct plant. 
 
 Plate VIII. Jig. 5. a, cells magnified 400 ; b, magnified 800 diam. 
 
 Genus 14. SICTTOSFHAIRIUni. Nag. (1849.) 
 Cells elliptic, with thick confluent mucous investment, com- 
 bined in numbers into free-swimming one-layered hollow- 
 globular families, one always at the ends of delicate threads 
 ■which proceed from the central point of the family, and which 
 become repeatedly branched towards the periphery ; division at 
 the commencement of a series of generations in all directions of 
 space ; afterwards, as regards the middle point of the aggre- 
 gate family, as a rule, alternating only in the two tangental 
 directions. 
 
 Only three described species, all of which have ocomred in the British 
 Ifiles. 
 
 Dictyosphaezium Ehzenbergianum. Nag. Einz. Alg. p. 73. 
 
 Families aggregated in a globular, or broadly elliptical 
 figure ; cells elliptic, very minute, about one-third as broad as 
 long. 
 
 Size. Cells •004--0075 mm. (Rabh.), •004--007 mm (Kirch.). 
 
 Rabh. Alg. iii. 47. Kirch. Alg. Schl. p. 106. 
 
 Amongst Confervce. 
 
 " This form is very minute, and in suitable places, common, the 
 families in the aggregate forming a globular, or broadly elliptic, or 
 sometimes suboubical figure ; the rate of growth of the delicate thread 
 being equal all round, the cells at the ends of each of its dichotomous 
 ramifications stand at nearly equal distance from the original centre j 
 hence the regular figure of the aggregate family. The individual cells 
 are elliptic, and very minute." — Archer. 
 
 Plate IX. Jig. 1. Families magnified 400 diam. ; b, fragment with 
 cells X 400 diam. j c, variety with spherical cells. 
 
PALMELLAOE^. 21 
 
 Dictyosphaeiriuin zenifoxme. Buln. Hedwigia ii. 22. 
 
 Families aggregated in an irregular form ; cells reniform, 
 nearly twice as broad as long. 
 
 Size. Cells -OOS-'OOQ mm. (BaJA.), •006--01 x •01--02 mm. 
 {Kirch.). 
 
 Eabh. Alg. iii. 47. Eabh. Exs. 789. Archer in Micro. 
 Journ., 1868, viii. p. 65. Kirch. Alg. Schl. p. 106. 
 
 In p6ols. Near Snowdon, N. Wales. 
 
 " This plant posseaaes larger families than D. Ehrenbergianum, which 
 are irregularly shaped, seemingly owing to the development of the 
 delicate supporting fibre not going on in the same regular manner as in 
 the preceding species, and the cells themselves are much larger and 
 reniform." — Archer. 
 
 Plate IX. Jig. 2. a, b, plants magnified 400 diam. ; e, portions ahow- 
 ing filament. 
 
 Dictyosphxziuni constzictum, Archer {Mior. Journ., 1866, jb. 128) 
 having been afterwards found to produce zygospoi'es (see " Micro. 
 Journ.," 1875, p. 415), has been transferred to the Desmidece 
 in company with Cosmocladium, to which genus it seems to be 
 
 ladium Saxonicum, DeBary, is sometimes placed by 
 
 (as in Eabenhorst's Algae) in this family. But, as 
 
 ; demonstrated in "Flora" (No. 21,1865), the cells 
 
 ed in the same manner as in Cosmarium, and therefore its 
 
 er place is with the Conjugatce, as one of the DesmidecB. 
 
 .1, has been found in North Wales. 
 
 Gbnus 15. HORMOSPOKA. Breb. (1810.) 
 Thallus tubular, gelatinous, swimming free. Cells oblong, 
 or oval, green, arranged in simple longitudinal series (families), 
 either remote from each other, or more or less united at the 
 poles. Tegument thick, confluent, contained within the broad 
 gelatinous tube, which is either simple or branched. 
 
 * Tubes simple. 
 Hozmospoza inuta.bilis. Breb. Mem. Fal. 1840. 
 
 Tubes intricate, more or less broad, or parallel and coalescing ; 
 cells twice as long as broad, broadly rounded at each end ; 
 tegument very thin. 
 
 Size. Cells -Ol 1-'017 mm., tube diam. -043 mm. (Rabh.). 
 
 Eabh. Alg. iii. 48. Breb. in Ann. des Sci. Nat., 1844, t. i. 
 f. 2. Kirch. Alg. Schl. p. 108. 
 
 In boggy pools. Ireland. 
 
 Plate X. Jig. 1. a, portion of filament X 300 ; b, same breaking up 
 X300. 
 
22 COCCOPHYCE^. 
 
 Hozmospora tzansvezsalis. Breb. 
 
 Tubes slimy, equal or undulate : cells ovate-oblong or fusi- 
 form, disposed transversely in a moniliform series ; contents 
 granular. 
 
 Size. Diameter of tube -075- -12 mm. 
 
 Eabh. Alg. iii. 49. 
 
 In bogs. 
 
 Hate X. fig. 3. a, portion of filament X 200 diam. ; h, portion X 
 400diam. 
 
 ** Tubes hranched. 
 
 Hozmospoza zamosa. Thwaites. 
 
 Tubes broad, gelatinous, irregularly branched ; cells oval or 
 nearly cylindrical, obtuse at the ends, either remote from each 
 other or connected, twice as long as broad ; contents green, 
 with green laminae radiating from the centre. 
 
 Thwaites in Harvey Phy. Britt. t. 213. Eabh. Alg. iii. 49. 
 
 In brackish and salt water, attached to Cladophora. 
 
 The filaments in tUs speoisB, unlike those of the preceding two 
 species, are branched. 
 
 Hate X. fig. 2. a, portion of filament X 20O ; b, small portion with 
 cells X 400. 
 
 Genus 16. CTLINOROCAPSA. Beinsch. (1867.) 
 
 Cells sphserical or ellipsoid, membrane thick, either with a 
 three or fourfold tegument, or naked; cells associated in a 
 linear series in families, enclosed in a cylindrical hyaline gela- 
 tinous tube ; cells dividing transversely. Propagation by 
 gonidia uncertain. Cell contents green, granular, with a single 
 chlorophyllose corpuscle. — Beinsch Algenflora, p. 66. 
 
 CyUndrocapsa involuta. JReinsch Algen/lora, tab, VI. /1 1. 
 
 Cells ellipsoid, ultimately involved in a fourfold tegument, 
 which is expanded at the poles. 
 Size. Cells •023--03 mm. diam. 
 
 This plant has occurred in Ireland, as recorded by Mr. W. Archer, in 
 " Grevillea" (Vol. in. p. 40), with the following observations : — 
 
 " Admitting the identity, of which I myself do not donbt, though not 
 previously having seen examples, that anthor's description of this 
 minnte sdga does not appear quite complete, as he omits to mention that 
 the cylindrical hyaline envelope of the cells, combining them into a 
 fi-ond, is closed at both extremities, roonded oS at the upper, and some- 
 what produced, tapered and thin, slightly dilated into a scutate organ of 
 attachment (to foreign objects) at the lower extremity. Thus the ex- 
 tremities appear to be difEerentiated into a basal and apical. The Irish 
 
PALMELLACEiE. 23 
 
 / 
 plant agreed with Eeinsch's in the dimensions of the cells, their oval 
 figure (trnnoate after division, whilst closely apposed, and until fall size 
 is again attained), their longer diameter posed in the direction of the 
 length of the cylindrical filament and in their being involved by a 
 number of concentric hyaline investments standing off from the cells at 
 the poles, closely applied 'at the sides ; not, however (as Reinsoh shows) 
 uniformly four, but two, three, or four, and standing ofE from the cells, 
 not equidistantly, bat at different distances. It is, however, quite 
 possible that where the fewer number only of laminae of the envelopes 
 were apparent, others may have been present, but so closely applied to 
 the cells (and to each other) as to appear as if absent. Just as depicted 
 by Eeinsch (though his figure be rather stiff), I saw some of the cells 
 undergoing self-division, the fission always taking place through the 
 shorter diameter, the new cells, at first flattened at the ends, then grow- 
 ing as long as the older, and becoming rounded off, and thus the longi- 
 tudinal direction of the cells is maintained. Thus this form is unlike 
 Cylindrocapsa nuda (Eeinsch), in which the oval cells are placed trans- 
 versely, and appear to be without the loose outer envelopes. The 
 author does not state that the contents are not a bright, but a dull lurid 
 green, very opaque. On endeavouring to preserve this plant, it ' kept ' 
 not at all, colour became lost, envelope shrivelled, and even after a 
 couple of days the examples did not represent the same thing as when 
 fresh. 
 
 " Thus the morphology of the plant points to an affinity with Hormo- 
 spora, Breb., which, too, has its forms with the elliptic cells placed 
 longitudinally {S. mutabilis and others) and transversely {S. transver- 
 salis), but no JSbrmospora, except H. ramosa, Thwaites, appears 
 attached j the contents, too, are bright green, and seem to show a 
 qharaoteristio internal arrangement not seen in Cylindrocapsa ; the 
 outer investment is also more mucous. As a form, or a form-species, 
 (for, doubtless, such as those belonging to Cylindrocapsa and Hormo- 
 spora can all be accounted no more, so long as no reproductive process 
 is known) the present plant {Cylindrocapsa involvtd) is, pe/r se, abun- 
 dantly distinct. It appears to be very rare, so does C nuda, 
 which I only once met with ; neither is recorded by Eabenhorst in 
 'Flor. Enrop.' 
 
 " But whether these Cylindrocapsa-forms be mere stages of other 
 growths — mere form-species — or permanent parthenogenetio species — 
 they are entitled to hold a place for purposes of reference until happily 
 more be, if ever, known as to their development and their right to 
 rank as independent plants." — Grev. III. 40. 
 
 Plate IX. Jig. 3. Portions showing spores X 400 diam. 
 
 Cylindzocapsa nuda. Beinsch Alg. p. 67, t. 6, f. 2. 
 
 Undivided cells ellipsoid, membrane thick, without teguments, 
 filaments now and then thickened and enclosing four cells. 
 Size. Tube •023--03 mm. diam. 
 In streams. Ireland. 
 
 Cienkowski's* researches on Cylindrocapsa involida achieved such im- 
 portant results that they must be indicated here, since the reproduction 
 will, doubtless, be identical in both species. 
 
 " This alga possesses antheridia and oogonia. The oogonium is a 
 globular inflated joint, it consists of contents and wall; the first presents 
 
 * Cienkowski, " Zur Morphologic der Ulotricheen," in Melanges Acad. 
 Imp. de St. Petersburg, t. ix. p. 531. 
 
24 coccoPHycE^. 
 
 a protoplasmic gonosptere, coloured by cMoropliyll, containing nnmerous 
 starch grannies ; it presents at one point of the periphery very often a. 
 clear spot. The gonosphere is loosely enclosed by the several (3-6) con- 
 centric gelatinous (as it were swollen or expanded) membranes. Sach 
 oogonia lie either several together, forming a moniUform chain, or they 
 present themselves in the middle of a series of antheridia, or between 
 unaltered vegetative joints, npon which, fnrther on, mayabnt antheridia. 
 Cylindrocapsa ia thus monoicons. At both poles of the oosfoninm the 
 coats are produced into a short cylindrical process j adjoining processes 
 are mutually apposed. The size of the oogonia varies ; it may reach 
 042 mm., the gonosphere "024 mm. 
 
 " The antheridia are discoid or sphseroidal little cells, like the oogonia 
 possessing a multi-laminated coat, they may form a long series or little 
 groups of pairs ; they' are often enveloped in twos or fours by numerous 
 laminae. The contents are clear reddish yellow. The male cells (like 
 the vegetative) are formed by binary division of the mother joint, with 
 the distinction that they cease to grow, remain smaller, and gradually 
 assnme the yellowish red colour. Each antheridium developes by divi- 
 sion of its contents two spermatozoids. At maturity they are ejected 
 with a jerk ; when free, they fie for a while motionless enclosed in their 
 gelatinous envelope. Presently they assume a tremulous motion, at last 
 bursting the vesicle and swimming about. They are protoplasmic fusi- 
 form bodies of about -OlS mm. in length, contents sparing, yellowish 
 red ; at the anterior hyaline point are borne two flagella, below which 
 are two minute pulsating vacuoles. 
 
 " Shortly after their exit they are to be found in the neighbourhood 
 of the oogonia. The whole cavity of the oogonium becomes pushed out 
 laterally, dissolving and leaving an opening at the apex of the expansion. 
 The spermatozoids seem now to be no way aimless in their movements, 
 their whole object being seemingly to effect a penetration ; with great 
 energy they drive against the wall, and retreat, and so persist for hours, 
 until at last the movement ceases, and they shrink into formless little 
 masses. The actual conflnenoe of the spermatozoid with the gonosphere 
 was not observed, but the conclusion drawn by the author seems to be 
 legitimate. 
 
 " The next change consists in the appearance of a thick gelatinous 
 stratum directly on the surface of the gonosphere, which soon hardens 
 into a doubly contoured membrane. After some days the chlorophyll with 
 the starch grannies gradually disappear, becoming replaced by the 
 reddish-yellow oily substance. In this way we obtain from the gonosphere 
 an oospore surrounded by the m neons layers of the oogonium. The 
 author could never see any further development ; they lasted the whole 
 autumn and winter without the slightest alteration. 
 
 " In some instances the gonospheres on having become enclosed by 
 the gelatinous envelope began to germinate ; they divided into two 
 segments, each then becoming clothed by its own gelatinous envelope, 
 and soon divisions followed just as in the ordinary vegetative joints. 
 The author supposes that these still green gonospheres could not have 
 been fertilized, and that only the latter pass over into a state of rest." 
 — Quart. Joum. Micr. Sci., 1877, p. 181. 
 
 Genus 17. HTDKUKUS. Ag. (1824.) 
 
 Thallus adnate, gelatinous, more or less firm, tubular, elon- 
 gated (2-4-12 inches long), sometimes variously divided, sticky, 
 surface naked or densely covered with delicate fibres, which at 
 times are fasciculate. Cells in the beginning globose, or snb- 
 
PALMELLACE^. 25 
 
 globose, afterwards elongated, or elliptic, sometimes conoid, one 
 or other pole colourless, arranged more or less regularly in longi- 
 tudinal families ; tegument thick, at .length diffluent, cells 
 dividing in one direction, chiefly at the apex or periphery of the 
 thallus. Propagation by means of agile gonidia. 
 
 Hydzuzus penicellatus. Ag. Syst.p.ii. 
 
 Thallus rather cartilaginous, olivaceous, of variable thickness, 
 simple and naked below, divided above, and villous with dense 
 fibrils. Internal cells elliptical or somewhat lanceolate ; tegu- 
 ment very thin, scarce visible ; contents homogenous. 
 
 Rabh. Alg. iii. 50. 
 
 Hydrurus fcetidus, Vauch. Kirch. Alg. Schl. p. 106. " 
 
 var. e. Ducluzelii. Rabh. Alg. in. 50. 
 
 Thallus from an inch to a foot long, oftentimes sparingly 
 branched, plumose with very dense fibrils. 
 
 Size. Cells ■006--0095 mm. {Rabh.). 
 
 Hydrurus Ducluzelii, Ag. Consp. p. 27. Hass. Alg. t. 77, f. 
 3. Rabh. Exs. 176, 873, 1193. 
 
 Batrachospermum myosurus, Ducluz. Conf. Montp. p. 76. 
 
 Palmella myosurus, Lyngb. Hydr. t. 68, E. 
 
 Cluzella myosurus, Bory. Diet. iv. 234. 
 
 In alpine rivulets, on stones, rocks, &c. 
 
 " Root scutate, blackish, hard. Fronds clustered, solid, very gela- 
 tinous, 2-6 inches long or more, 2-4 lines in diameter, freely waving in 
 the water, attenuated towards the apex, branched; branches scattered, 
 alternate, elongate, slender, beset with other more slender, short ramuii. 
 Gelatinous mass pellucid, viscid, colourless under the microscope, without 
 apparent margin, unless as the grannies imbedded within its substance 
 indicate such ; these are globose, green, formed on the stem and primary 
 branches, most densely set in the ramuii, especially towards the margin. 
 Colonr of the recent frond brownish-olive, or dark brown, in drying 
 green ; of the granules both recent and dry green." — Jjynghye. 
 
 Odour in a recent state very ofEensive. 
 
 One or other of the many forms of this species has been called 
 Palmodactylon subramosum, Nag., but we have not, as yet, seen any 
 true British representative of that genus. 
 
 Plate X. Jig. 4. a, natural size ; b, portion magnified 400 diara. 
 
 Genus 18. NEPHROCYTIUM. Niig. (1849.) 
 Cells oblong kidney-shaped, with a dorsal chlorophyllose 
 vesicle, 2-4-8-16 associated in free swimming families sur- 
 rounded by an ample oval or kidney-shaped tegument. Pro- 
 pagation unknown. 
 
 Only two Enropean species, both of which have been found in the 
 British Isles. Both are usually found together, and it is possible that 
 hereafter they may be referred back to one species, as Nageli pro- 
 posed. 
 
26 coocoPHYcEa:. 
 
 Nephrocytiiliu Agsurdhianum. Nag. Einz. Alg. p. 80. 
 
 Cells pale green, almost homogenous, 4-6 times as long 
 as broad, spirally arranged, in families of 4-8 cells ; tegu- 
 ment thin which encloses them, length 2-3 times the breadth. 
 
 Size. Cells diam. -OOSS-'OOTS mm. (Eabh.). 
 
 Eabh. Alg. iii. 52. Nag. Einz. Alg. {forma minor'), t. iii. 
 C. a-h. Kirch. Alg. Schl. p. 112. 
 
 In ditches, bogs, &c. 
 
 Mate XI. Jig. 1. a, b, families ; c, end view j d, free cells. All 
 magnified 400 diam. 
 
 Nephrocytium Naegelii. Grun. Babh. Alg. III. 52. 
 
 Cells dark green, granular, twice as long as broad, irre- 
 gularly disposed, families usually composed of 16 cells ; tegu- 
 ment thick. 
 
 Size. Cells diam. ■011--022 mm. (Eabh.). 
 
 Nepiirocytium Agardhianum, majus Nag. Einz. Alg. t. iii. 0. 
 fig. i, k, p. Kirch. Alg. Schl. p. 113. 
 
 In similar or the same places as the foregoing, with which 
 it is often associated. 
 
 Plate XI. Jig. 2. a, b, c, family groups ; d, free cells. All magnified 
 400 diam. 
 
 Genus 19. OOCTSTIS. Nag. (1855.) 
 
 Cells oblong, chlorophyllous, either solitary or binate, qua- 
 
 ternate, or octonate ; contained at first within an ample simple 
 
 mother cell, at length free by dissolution of the membrane. 
 
 This genns, as Mr. Archer has observed (Micr. Jonm., 1877, p. 105), 
 comes very near Nephrocytivm,, the seemingly only very tangible dis- 
 tinction (it is a very constat one at the least), being the reniform (not 
 elliptical) cells in the latter genns ; bnt as forms merely, of more or 
 less frequent occurrence, those referred to both the genera are indeed 
 very distinct and constant. 
 
 Oocystis gigas. Archer, Quart. Jowrn.Muyr.Sci., W17, p. 105. 
 Mother-cell broadly elliptic, almost subglobose, large ; family 
 usiially consisting of two cells. 
 
 Size. Mother-cell ■06--07 X •05--06 mm. 
 
 In pools. Ireland. 
 
 The broadly elliptical cells are very large, and are really subsphaerical. 
 " The cell wall," Mr. Archer says, " is by comparison very thick, with 
 the somewhat nodular little thickening at each pole; the chlorophyll 
 granules, in examples in which these were not too dense, could be seen 
 arranged parietally in a, beautifully and curiously regular reticnlate 
 manner, the ' meshes or interspaces of the interior surface of the wall 
 being bare of them. He had only seen two young cells within theex- 
 panded mother-cell, four, eight, to sixteen being common in Oocystis 
 Haegelii. In examples about to produce young individuals, the contents 
 
PALMELLACE^. 27 
 
 became more dense, and the reticnlated arrangements lost, or ratber, 
 perhaps, more properly speaking, the interspaces become clothed with 
 chlorophyll granules. At first glance this might be mistaken, under a 
 low power, for that small form of Eremotplicera viridis, which origi- 
 nates when the individuals of the ordinary lai'ge form produce simul- 
 taneously four, in place of two daughter cells j but the evident elliptic 
 figure and the thickened poles, as well as the different arrangement of 
 the chlorophyll contents, would, on closer inspection, at once distinguish 
 them. Mr. Archer has drawn attention to the seemingly curious very 
 great expansion of the wall of the mother-cell, almost looking as if in 
 anticipation, rather than as in consequence of the growth of a young 
 ' brood ' of two, four, eight, or sixteen daughter-cells, so much so that 
 it almost had the aspect of a fresh growth, rather than that of a mere 
 swelling up of the old membrane." — Quart. Jowrn. Nicr. Sci., 18V7, 
 p. 105. 
 
 Oocystis setigeia. Archer, in Qucvrt. Jowrn. Micr. Sci., 1877, p. 194. 
 
 We are unable to give any description of this species which, 
 as far as we are aware, bears only a manuscript name. Neither 
 are we able to give figures of either species, although we hope 
 to do so hereafter. 
 
 Genus 20. DIiaORFHOCOCCUB. Br. (1849.) 
 Cells united in fours on very short branches, dissimilar, the 
 two intermediate contiguous oblique, obtuse ovate, the two 
 lateral, opposite and separate from each other, lunate ; families 
 free swimming, in botryoid clusters. 
 
 This genus is allied to Dictyosphcerivm, next to which it should have 
 been placed. 
 
 Dlmozpho coccus Innatus. Br.Alg. Uni.2>'44. 
 
 Green, apices of the cells hyaline. 
 Size. Cells longitudinal diam. •01-*02 mm. 
 Babh. Alg. iii. p. 36. Archer, Quart. Journ. Micr. Sci., 
 1872, pp. 195, 197. 
 
 Floating in pools. N. Wales. 
 
 We have been unable to make a successful drawing from the 
 specimen we possess of this Alga, as we have not seen it living. M r. 
 Archer, on reporting upon its occurrence in Ireland, criticised the only 
 figure extant (in Eabenhorst's Alg. Eur.) in the following terms : " The 
 upper or outermost cells do not, as they are made to seem, or as the 
 original description might lead one to infer, stand above the larger and 
 lower (inner) cells as upon a common stipes, but the former grow off 
 from the latter, and remain joined thereto by a short pedicle. The inner 
 eels are broadly reniform, and two stand opposite to each other at the 
 apex of the supporting stipes, so as to present a lunate figure, and from 
 the lower part of the sinus made by these it is that the pedicle of each 
 of the pair of secondary, more or less reniform, but unequally lobed, 
 cells (one from each lower cell) starts, the smaller lobes of these latter 
 overlapping each other, and appearing, in a crowded cluster, like one 
 cell, only of smaller dimensions, concentrically posed above the lower 
 
28 COCCOPHYCE^. 
 
 cell, and as if on » common stipes, that is, as it all were ' in ramnlis 
 — qnaternatim conjunctae.' " The larger lower cells are com- 
 bined, inter se, by a soft irregular oolonrless furcated^ (almost as if 
 shrivelled) stalk, into a crowded colony or family. This branched cluster 
 of cells requires to be broken np and pressed ont ere the arrangement 
 referred to can be seen. The structure and mode of arrangement of the 
 cells (which are bright green, with a, pale narrow little space at the 
 upper extremity, and with large chlorophyll granules) becomes thus of 
 somewhat complex appearance, nor did it appear to have been made ont 
 fully by Braun himself, as conveyed by his description. — See Quart. 
 Joum. Micr. Science, 1872, pp. 195, 198. 
 
 Genus 21. MISCHOCOCCUS. Naff. {184,9.) 
 
 Thallns dichotomously branched, bearing the terminal cells. 
 Cells globose, tenninal, geminate or quaternate. Division of 
 cells in one direction. Propagation by zoogonidia. 
 
 This genus is confined at present to a single species. 
 
 Kischococcus confeiTicola. Niiff. Eirtz. Alg. p. 82. 
 
 Cells globose, even, geminate, temate or quaternate, on the 
 tips of the branches, bright green, delicately granular, destitute 
 of a chlorophyllose vesicle ; stem hyaline, spuriously articulated, 
 often swollen at the angles. 
 
 Size. Cells •0045--009 mm. (Eabh.). 
 
 Kabh. Alg. iii. p. 54, fig. 29. 
 
 Attached to filamentous Algse in ditches, near Stafford, 
 August, 1849 (Rev. R. C. Douglas). 
 
 This interesting little plant is liable to be overlooked on account of its 
 small size and the delicate hyaline stem, only the pair, or more, of little 
 globose green cells being at first visible. 
 
 Hate Jd. Jig. 4. a, two plants parasitic on Conferva; J, young 
 plants; c, terminal branches with 4 cells ; (2, swollen joints of stem; e, 
 free cells. All magnified 400 diam. 
 
PROTOOOOCACE^. 29 
 
 Family II. PROTOCOOCACBtE. 
 
 Unicellular algse, in the strictest sense, chlorophyllous, with- 
 out terminal growth, or ramification, without a vegetatiTe 
 generation of cells. Either single, segregate, or associated in 
 families. Cells of the families either indefinitely increasing in 
 number (then forming families) or of a definite number (then 
 forming a ccenobiuni). 
 
 Propagation by means of gonidia, arising in the mother cell 
 by free cell formation ; gonidia of two kinds, the one -larger, 
 macrogonidia, the other smaller, microgonidia ; the former 
 oblong, mostly produced anteriorly into a pale bi-eiliate beak, 
 rounded and greenish at the posterior end, developing into an 
 individual plant ; the microgonidia similar to ttiese, and also 
 motile, but passing after a short time into a quiescent state, and 
 at last into resting spores, or hypnospores. 
 
 This family is usually subdivided into the following sub- 
 families : — 
 
 1. Protococce^. 5. Hydrodiotyb^. 
 
 2. ChLOBOOOOCAOBjE. 6. OPHtOCYIIBiE. 
 
 3. PolybdribjB. 7. Pbdiastre^. 
 
 4. SOBNBDESMB^. 8. SoRASTRBiB. 
 
 9. CHARAOIEiE. 
 
 Many of these small sab-families include but a single genus, so that, 
 in effect, the character of the aab-family is that of the genaa j hence 
 they are of little value, especially in a local flora. 
 
 Sub-Family 1. Pbotococoej). 
 
 Cells sphaeroid, segregate ; cytioderm thin, hyaline, without 
 integument, swimming free, or, when not growing in water, 
 forming a thin pulverulent stratum. Contents in the beginning 
 homogenous, then granular, green, or reddish. 
 
 Only one genus has yet found a place in this sub-family, of which 
 one species is British. 
 
 Genus 22. FBOTOCOCCUS. Jg. (1824.) 
 Characters the same as in the sub-family. Propagation by 
 mobile gonidia. 
 
 Fxotococcus viridia. Ag. Babh. Alg. in., 56. 
 Cells small, segregate, accumulated in a broadly expanded 
 stratum, of a yellowish green colour, either pulverulent, or, 
 during moist weather and after rain, somewhat gelatinous. 
 Size. Cells •0025--U04 mm. 
 
 On the trunks of trees, fallen branches, and damp walls 
 throughout the year. 
 
 It is very probable that this is only a condition of Pleurococcus vul- 
 ga ris. 
 
 Plate XII. fig. 1. Cells magnified 400 diameters. 
 
 P 
 
30 COCCOPHTCE^. 
 
 Sub-Family 2. Chloeocoocaoe^. 
 
 Cells sphsBToid, either single and free, furnished with a 
 chlorophyliose vesicle and a pale lateral spot, sometimes with an 
 ample tegument, or more often accumulated in strata or little 
 clusters. Propagation by zoospores, formed by division of the 
 cell contents, escaping by rupture of the cell wall. 
 
 Genus 23. CHLO&OCOCCUIH. Fries. (1825.) 
 
 Cells subglohose, single or in clusters. Characters the same 
 as the sub-family. 
 
 A. Species green. 
 ■f Tegument thin. 
 
 Chloiococcum hamicolam. {Nag.) Raih. Kr. Fl. Sachs, 137. 
 
 Stratum effused, dark-green, pulverulent ; cells globose, 
 variable in size, often many united in families, involved in a 
 common hyaline tegument ; cell membrane thin, but thickening 
 with age ; contents at first pale or yellowish-green, homo- 
 genous, at length dark-green, granular. 
 
 Size. Cells -017 mm. diam., or less. 
 
 Rabh. Alg. iii. 58. 
 
 Cystococcus humicola. Nag. Einz. Alg. 85, t. 3, f. E. 
 
 On the naked ground (A. W. Wills). 
 
 Plate XII. fig. 5. Cells and family magnified 400 diameters. 
 
 Chloxococcum frastulosam. {Carm.) Bdbh. Alg. iii., 59. 
 
 Thallus effused, pulverulent, green ; cells globose, of medium 
 size, associated in families which are involved in a broad hyaline 
 homogenous envelope. 
 
 Size. Cells -007 mm. diam. ; families to '04 mm. diam. 
 
 Hcematococcus fi-ustulosus, Hass. Alg. 380, t. 81, f. 1. Eng. 
 Fl. v., p. 395. Harv. Man. 181. 
 
 Palmella frustulosa, Carm. MSS. 
 
 On moist rocks. 
 
 " It occra^ in the form of a greyish black, fragmentary scnrf . On the 
 slightest pressure it separates into corpnscles of various forms, but 
 mostly sphaerical, hyaline under the microscope, surrounded by a mem- 
 branous envelope, and including several granules." — Carm. 
 
 Plate XII. fig. 2. Families magnified 400 diameters. 
 
 Chloxococcum muxorum. {Grev.) Rabh. Alg. iii., 61. 
 
 Thallus crustaceous, yellowish-green ; cells subglohose or 
 oblong, with a rather thick hyaline mucous envelope ; cell con- 
 tents seruginous-green, homogenous. 
 
 Size. Cells, including envelope, •016-"02 x "01 mm. 
 
 Grev. Sc. Crypt. PL, t. 325. 
 
 Hcematococcus murorum, Hass. 323, t. 81, f. 4. 
 
 On walls. 
 
PROTOOOCCACEiE. 31 
 
 We have retained this in its present position in deference to Raben- 
 horat, to ■whom the species must have been known. At the same time 
 its BBruginous green oolonr seems to indicate an afBnity with Phycochro- 
 mophyceos rather than the present order. 
 
 " Plant producing spots on walls and stones of a yellowish green oolonr, 
 and at first very small, but afterwards indefinitely larger, from a nnmber 
 becoming confluent. First discovered in this country by the Rev. M. J. 
 Berkeley on the freestone walls of Christ College, Cambridge." — 
 Qreville, 
 
 Plate Xll. fig. 4. Cells magnified 400 diameters. Some undergoing 
 division. 
 
 ft Tegument thick. 
 Chlozococcum gigas , Qrun. in Baih. Alg., No. 1436. 
 Stratum thin, green, mucous ; cells globose, large, either 
 single or associated in small families, always involved in a broad, 
 distinctly lamellose hyaline tegument. 
 
 Size. Cells •012--017 mm. diam. without the hyaline mem- 
 brane. 
 
 Protococcus gigas, Kntz. Phy. Gen. p. 145. 
 In pools, on walls and glass windows. 
 
 One of the finest species in this genus, and'possibly not uncommon. 
 We have met with it two or three times, but not in any great quantity. 
 It must not be confounded with Qloeocystis ampla. 
 
 Plate XII. fig. 3. Cells magnified 400 diameters, b, in different stages 
 of division. 
 
 B. Species red, rusty, or orange. 
 
 No British species in this section recorded. 
 
 Sub-Family 3. Poltedeie^. 
 
 Cells single, segregate, free swimming, compressed, 3-4-8 
 angled ; angles more or less produced, sometimes radially elon- 
 gated, either entire or bifid, mostly armed, oblong-elliptic when 
 viewed laterally, rounded or rather truncate at the ends. Cell- 
 membrane thin, even. Chlorophyll-mass mostly granular, 
 equally distributed through the cell, sometimes with 1-4 reddish 
 oil-drops. Propagation unknown. 
 
 Genus 24. FOLYEDRIUIH. Nag. (1849.) 
 
 Characters the same as above for the sub-family. 
 
 A. Angles entire. 
 Polyedzium gigas. WiWr. Sotvattensalger, p. 33, *. 4, /. 4. 
 Cells irregularly pentahedrical (rarely hexahedrical), angles 
 obtuse, sides concave. 
 
 Size. Maximum diameter of cells "OeS-'OTS mm. ; minimum 
 diameter •035-'045 mm. 
 
 Archer, in Quart. Journ. Micr. Science xvii. (1877), p. 105. 
 
 In standing pools. 
 
 This large and distinct species has the angles rounded and unarmed. 
 Plate XIII. fig. 1. a, b, e, cells in three positions, magnified 400, 
 after Wittrook. 
 
32 
 
 COCCOPHTCK^. 
 
 Polyedrium tetzaediicnm. Nag. Einz. Alg. 
 
 Cells regularly tetrahedrical ; angles obtuse, tnucronate. 
 Size. Cells -OlS-'OS mm. diam. 
 
 Eabh. Alg.iii. 62. Archer, Mior. Journ., 1866, p. 62. 
 In pools. 
 
 This might possibly be mistaken for the end view of some species of 
 Staurastnim, agajnst which error it is essential that beginners should be 
 cautioned. 
 
 Plate Xlll. fig. 3. Cells magnified 40O diameters. 
 
 B. Angles radiato-elongated. 
 Polyedrium longispinmn. {Periy.) Rahh. Alg. iii., 62. 
 Quadri-radiate, radii thin, elongated, scarcely thickened into 
 a body in the centre. 
 
 Size. Length of arms -OS-'OS mm. 
 
 Phycastrum longispinum, Perty KI. Lebensf. t. xvi., f. 30. 
 
 In pools. N. Wales (4. W. Wills). 
 
 A pecnliar species, which at first sight seems to have but little re- 
 lationship with the other species figured. It is often found associated 
 with Desmids, and delights in similar localities. 
 
 Plate Xlll. fi^. 2. a, b, o, d, cells magnified 400 diameters. 
 
 C. Angles lohed. 
 Polyedrium enorme. (fialfs) RaVh. Alg. m., 63. 
 
 Cells irregularly tetrahedrical, with the angles produced, 
 hyaline, deeply bilobate ; sometimes repeatedly bilobed, with the 
 lobes mucronate. 
 
 Size. Cells •025--04 mm. diam. 
 
 Staurasti-um enoi-me, Ealfs, t. 33, f. 11. 
 
 In pools. 
 
 " Frond very irregular and variable in form. Sometimes the front 
 view differs but little from the end one. Usually, however, there is a 
 slight constriction at the junction of the segments, but I have never ob- 
 served any difference in the endochrome at that part. The spines, which 
 are almost confined to the angles, are irregular, some simple and some 
 branched. The end view has three or four broad and very irregular 
 lobes ; these are spinous and more or less emarginate, and frequently 
 one lobe is much broader and more spinous than the others. The spines 
 on each lobe form two groups, separated by the notch ; they vary much 
 in size, and are either simple and subulate, or else forked ; sometimes 
 the forked spines are again divided at the apex." — Rolfs. 
 
 A very variable plant, formerly included with the Desmidiese, but 
 separated on account of its different mode of propagation. 
 
 Plate Xlll. fig. 4. Cells magnified 400 diameters. Lateral and end 
 views. 
 
 Sub-Family 4. ScENEDESME.a!. 
 
 Cells elliptic, ohlong, or cylindrical ; cell-membrane very thin ; 
 cell-contents at first homogeneous, afterwards granular ; chloro- 
 phyllose vesicle central or sublateral, and often a lateral colour- 
 less spot ; cells 2-4-16, either joined in a single series or forming 
 
PROTOCOCOACBJi;. 33 
 
 a coBnobmm. Propagation by division in the cells whence arise 
 gonidia, which unite themselves into a coeuobium within the 
 mother-cell, and are at length set free by the rupture of the 
 cell-membrane. 
 
 Genus 25. SCENEDESMUS. Meyen. (1829.) 
 
 Cells polymorphous, equal or unec[ual at the ends, often pro- 
 duced into a spine-like horn. Frond or family composed of 
 from 2 to 8 oblong, fusiform, or elliptic cells, connected into a 
 single or double continuous row ; propagating by means of the 
 repeated segmentation, in parallel planes, in one or two direc- 
 tions, of each of the cell- contents into one or more brood families 
 (not motile) , set free by the bursting of the parent-cell wall. — 
 Nageli. 
 
 A. Cells unarmed. 
 Sceuedesmus obtusus. Meyen. Babh. Alg. iii., 63. 
 
 Cells oblong or ovate, obtuse at the poles, 4-6-8 loosely con- 
 nected in a simple series, or joined obliquely, 3-5 times as long 
 as broad. 
 
 SizB. Cells -OOSS-'OO? mm. diam. 
 
 Ralfs Ann. Nat. Hist, xv., p. 404, t. 12, f. 8. Brit. Desm. 
 p. 193, t. 31, f. 16. Archer in Pritch. Infus. p. 753, t. 1, f. 
 37-39. Hass. Alg. p. 394, t. 92, f. 15. 
 
 In boggy pools. 
 
 This species appears to be mnoli less common than 8. guadricauda, 
 from all forms of which it may be readily distinguished, not only by the 
 difference in the form of the cells and absence of spines, but the remote- 
 ness of one cell from its neighbour and their alternation. 
 
 Plate XIII. fig. 5. Cells in families of 4 and 8, magnified 400 
 diameters. 
 
 Scenedesmus acutus. Meyen. Rabh. Alg. iii., 63. 
 
 Cells fusiform or ovate-fusiform, acute at each extremity, 
 2-4-6-8 united in a series, either single and straight, or double 
 and irregularly alternate ; 3-6 times as long as broad. 
 
 Size. Cells -OOSS-OOSS mm. diam. 
 
 Ralfs Ann. Nat. Hist, xv., p. 404, t. 12, f. 6. Brit. Desm. 
 193, t. 31, f. 14. Hass. Alg. 393, t. 92, f. 14. 
 
 In pools and boggy places. 
 
 va/r. b. obliquus. Babh. Alg. III., 63. 
 
 Cells elliptic, fusiform, arranged in two generally oblique 
 series, the outer cell of each not in contact with any of those in 
 the other series. 
 
 Scenedesmus obliquus, Ralfs Desm. p. 192, t. 31, f. 15. 
 EngUsh Botany, t. 2933. 
 
 Scenedesmus triseriatus, Ralfs Ann. Nat. Hist, xv., p. 403, t. 
 12, f. 7. 
 
3i 
 
 COCCOPHYCE^. 
 
 var. c. dimoxplius. Mabh. Alg. III., 63. 
 
 Cells acute, 4-8, placed evenly in a single row ; inner cells 
 fusiform, outer externally lunate. 
 
 Scenedesmus dimorphus, Ralfs. Ann. Nat. Hist xv., p. 403, 
 t. 12, f. 5. Brit. Desm. p. 191, t. 31, f. 13. Hass. Alg. 393, 
 t. 92, f. 13. 
 
 Formerly the typical form and its two varieties were regarded as three 
 separate species, but there scarcely seems sufficient reason for thus re- 
 taining them. Ralfs wrote of them long ago, " When the cells are nearly 
 uniform j!>'. fl£*?i^w5 haa some resemblance to S. dimorphus; but in the 
 latter the cells are more slender, never ventricose, and are arranged 
 quite evenly side by side. It is more difficult to distinguish S. acutus 
 from S. oMiqnns, and I am far from certain that Bhrenberg erred in 
 uniting them. The principal distinction is that in S. acutus the cells 
 form only a single series, which is nevertheless irregular, on account of 
 the alternate projection of the cells in opposite directions. In S. obViquus, 
 on the other hand, the cells by division form two distinct rows, which, 
 after separation, become two fronds." These characteristics are better 
 shown in Ralfs' figures than in our own, which are more intermediate, 
 and show an evident approximation to the typical form. 
 
 Plate XIII. fig. 6. a, cells of the typical form ; b, cells of the variety 
 dimorphus; c, oi the \asietj ooliquns. All magnified 400 diameters. 
 
 Scenedesmus antennatus. Breb. Ealf. Besm. t. S5, f. 27. 
 
 Cells fusiform, 2-4-8, joined in a single or double series, all 
 somewhat curved, usually ventricose, cuspidate at each extremity, 
 the apices bearing a hyaline globule. 
 
 Size. Cells ■002o--0035 mm. diam., -013 mm. long. 
 
 Eabh. Alg. iii. 63. Archer in Pritch. Infos, p. 753. 
 
 In pools. 
 
 " Scenedesmus antennatns resembles 8. acutus in form, and also in the 
 arrangements of the cells; but is distinguished from that and every 
 other species by having the attenuated points tipped by minute glo- 
 bules." — Ralfs. 
 
 At the time the above was written it had not been found in this 
 conntry, and is still the rarest species, if its specific identity can be 
 maintained. 
 
 Plate XIII. fig. 7. Cells magnified 400 diameters. 
 
 B. Cells armed. 
 Scenedesmas quadricauda. Breh. Ralfs Desm. 190, t. 31, /. 12. 
 
 Cells oblong-cylindrical, each extremity obtusely rounded, 
 2-4-8, narrowly united, either in a single or double series, all 
 straight, the outer cells at each end (and rarely some of the 
 intermediate ones) armed at each extremity with a recurved 
 spine. 
 
 Size. Cells -OOSS-'Ol mm. diam. to -022 mm. long. 
 
 Eabh. Alg. iii. 65. 
 
 Scenedesmus quadricaudatus, Ralfs Ann. Nat. Hist, xv., p. 
 402, t. 12, f. 4. Hass. Alg. 392, t. 92, f. 12. Jenner Fl. Tun. 
 Wells, p. 200. 
 
 In standing water. 
 
PEOTOCOCOACE^. 35 
 
 The commonest of Britiah speoiea. A variety has been described 
 which differs only in being entirely destitute of bristles. We can con- 
 firm Ralfs in his observation that the species of this genns frequently 
 make their appearance in clear water that is kept in glasses or bottles 
 and exposed to the light. He says that he has repeatedly noticed the 
 appearance of S. acutus var. oiliquiis in bottles containing DesmidUece, and 
 sometimes its rapid increase so as to outnumber its companions. Speci- 
 mens obtained in this manner, he adds, are frequently more or less 
 distorted. In little aquaria the present species often becomes a nuisance 
 from its profusion. 
 
 Plate XIII. fig. 8. Cells magnified 400 diameters. 
 
 8uh-Family 6. Hydeodiottej). 
 
 Individual cells oblong-cylindrical, united into a reticu- 
 lated saccate ccenobium, all fertile, some producing macro- 
 gonidia, which join themselves into a coenobium within the 
 mother- cell, others producing microgonidia, which are fur- 
 nished with two vibratile cilia and a lateral red spot ; these 
 escape from the parent-cell, and, after a brief motile period, 
 subside into protococcoid, thick-walled spores. 
 
 Genus 26. HTDRODICTYON. Roth. (1800.) 
 Characters the same as in the sub-family. 
 
 " The genus Hydrodictyon comprises, as far as known, but a single 
 species, which is common to North America and Europe. It grows in 
 great abundance in the neighbourhood of Philadelphia, especially in the 
 ditches and stagnant brick ponds in the low grounds below the city, 
 known as the ' Neck.' There it very frequently forms floating masses 
 several inches in thickness, and many feet in extent, so that with the aid 
 of a rake it could be gathered by the bushel. When thus in mass the 
 colour is very generally dingy and yellowish, although the fronds, when 
 in active vegetative life, are mostly of a bright, beautiful green. The 
 plant is in greatest profusion in June and July, after which time it 
 gradually disappears, until in the autumn it is scarcely to be found, but 
 early in the spring it reappears. The very young fronds are minute, 
 oval, cylindrical, filmy-looking closed nets, with the meshes not appre- 
 ciable to the eye j when growth takes place the fronds enlarge, until 
 finally they form beautiful cylindrical nets, two to six inches in length, 
 with their meshes very distinct, and their ends closed. In the bright 
 sunlight, they, of course, by virtue of the life functions of their ohlorophyl, 
 liberate oxygen, which, being free to the interior of the net, and its exit 
 barred by the fine meshes, collects as a bubble in one end of the cylinder, 
 and buoys it up, so that, the heavier ends sinking, the net is suspended, 
 as it were, vertically in the water. I know of few things of the kind 
 more beautiful than a jar of limpid water with masses of these little nets 
 hanging from the surface like curtains of sheen in the bright sunlight. 
 A few cells collected in the fall or early spring, if put into a preserving 
 jar, and the water occasionally changed, will multiply, and in a little while 
 become a source of frequent pleasure to the watcher. 
 
 *' As the fronds increase in size they are always in some way or other 
 broken up, so that, instead of being closed cylinders, they appear as 
 simple open networks of less or greater extent. The extreme length to 
 which the frond attains is, I think, very rarely over twelve inches, with 
 meshes of about a third of an inch in length. The construction of the 
 frond is always the same. It is composed of cylindrical cells united end 
 
36 COCCOPHTCE^. 
 
 to end in snch a way aa to form polygonal and mostly pentagonal 
 meshes, the size of which varies with the age of the plant. These cells, 
 which are closely conjoined, but have no passage-ways between them, 
 are capable of independent life, so that the Hyd/rodictyon may be looked 
 npon as an elaborate type of a cell-family, one in which cells are con- 
 joined in accordance with a definite plan, so as to make a body of definite 
 shape and size, yet in which each cell is an independent being, drawing 
 nothing from its neighbonra. The cells themselves are cylindrical, with 
 a thickish cellulose wall, and having no nuclei. Their chlorophyllous 
 protoplasm is granular, and is placed in the exterior portion of the cell, 
 forming thus, within the outer wall, a hollow cylinder, in which are im- 
 bedded starch granules, and whose interior is occupied with watery 
 contents. The Hydrodictyon cell, when once formed, is capable of growth. 
 but not of going through the usual process of cell multiplication by 
 division, so that the adult frond is composed of just as many and, in- 
 deed, the same cells as it had in its earliest infancy. 
 
 "No true sexual reproduction has as yet been discovered in the water- 
 nets. There have been described, however, two forms or methods in 
 which the species multiplies, both of them occurring by means of motile 
 zoosporoid bodies. In the one case these develop immediately into the 
 new plant, whilst in the other, before doing so, they pass through a 
 resting stage. Of the life history of the latter, the mityrogorUdia, I 
 have no personal knowledge. 
 
 " The investigation of the production and development of the niocro- 
 gonidia, however, has occupied considerable of the time devoted by 
 myself to the microscope, and I have seen large numbers of specimens 
 in almost all the stages of development. I have never been able to 
 detect any decided motion in the macrogonidia, 
 
 " They are formed in the protoplasmic stratum already alluded to as 
 occupying the outer portion of the interior of the ffydrodictyon cell. 
 The first alteration in this, presaging their formation, is a disappearance 
 of the starch granules, and a loss of the beautiful transparent green 
 colour. Shortly after this, even before all traces of the starch-grain 
 are gone, there appear in the protoplasm numerous bright spots placed at 
 regular intervals ; these are the centres of development, around which 
 the new bodies are to form. As the process goes on, the chlorophyl 
 granules draw more and more closely around these points, and at the 
 same time the mass becomes more and more opaque, dull, and yellowish 
 brown in colour. This condensation continues until at last the little 
 masses are resolved into dark hexagonal or polygonal plates, distinctly 
 separated by light, sharply defined Hues. In some the original bright 
 central spot is still perceptible, but in others it is entirely obscured by 
 the dark chlorophyl. The separation of these plates now becomes more 
 and more positive, and they begin to become convex, then lenticular, 
 and are at last converted into free, oval, or globular bodies. When 
 these are fully formed they are said to exhibit a peculiar trembling 
 motion, omtnally crowding and pushing one another, compared by A. 
 Braan to the restless, uneasy movement seen in a dense crowd of 
 people in which no one is* able to leave his place. Whilst the process 
 just described has been going on, the outer cellulose wall of the Hydro- 
 dictyon cell has been undergoing changes, becoming thicker and softer 
 and more and more capable of solution, and by the time the gouidia 
 are formed it is enlarged and cracked, so that the room is afforded 
 them to separate a little distance from one another within the parent- 
 cell. Now the movements are said to become more active — a trembling 
 jerking which has been compared to the ebullition of boiling water. 
 There is, however, with this a very slight change of space, and in a very 
 short time the gonidia arrange themselves so as to form a little net 
 within the parent-cell, a miniature in all important particulars of the 
 
PROTOOOOOACEJS, 37 
 
 adnlt By^odictyon. The primary cell wall now beooraes more and 
 more gelatinons, and soon undergoes complete solution, so that the 
 new frond is set free in its native element. 
 
 " It is evident that when the speoies is multiplied in the way just 
 described the birth of the new frond is consentaneous with the death 
 of the old cell. But when the Sydrodictyon disappear in the fall, it is 
 mouths before they reappear in the spring. It is, therefore, evident 
 there must be some other method of reproduction. This slow develop- 
 ment of new fronds takes place, aocording to Pringsheim, by means 
 of little motile bodies which he calls Dauerschwmrmer, which has been 
 translated in English Gh/ronispores (statospores, Hicks). M. Brauu stated 
 already some years since that sometimes, instead of the Hydrodictyon 
 producing the ordinary reproductive bodies (macrogonidia), there are 
 formed in the cells much smaller and more active bodies, the micro, 
 gonidia. The changes which occur in the production of these are very 
 similar to those already described as happening when the macro- 
 gonidia are formed. When the ohronispores are formed, however, they, 
 instead of uniting together, escape in a free, distinct condition with 
 the water. They are now small ovate bodies, with a large anterior 
 transparent space, to which are attached a pair of cilia, and their life 
 and history, according to Pringsheim, is as follows : — For a few hours 
 they move about very actively in the water, and then, dropping their 
 cilia, and acquiring an outer cellulose wall, pass into a quiescent stage, 
 in which they closely resemble ProtoGoccus granules. They are capable 
 of living in this state for a long time if kept in water. They can also 
 endure dessication if the light be excluded during the process, but if it 
 be present, they wither and die, and cannot be revivified. 
 
 " After a longer or shorter period, but never shorter than three months, 
 according to Pringsheim, they recommence their life, provided they be 
 in water. For four or five months after this the chief change consists 
 simply in au increase in size. The dark green protoplasm is arranged 
 around- the exterior of the cell ; within are the more fluid colourless con- 
 tents, the whole body still looking like a Protococcus cell. After a size 
 of about ^th mm. is attained, the endochrome divides successively into 
 several portions. The external layers of the surrounding wall now give 
 way in some spot, and allow the inner layers to protrude and form a sort 
 of hernial sac, into which the several endochrome masses soon pass, at 
 the same time assuming the well-known characters of true zoospores. 
 From two to five of these bodies are thus produced out of each original 
 microgonidium. They are large, ovate, biciliate, and, generally, soon 
 escaping from the hernial sac, move about actively in the water for a 
 few minutes. Sometimes, however, they settle down within the genera- 
 tive utricle. In either case, after a little time, they become motionless, 
 lose their cilia, and develop into polyhedral cells, which are structurally 
 remarkable for having their angles prolonged into long, horn-like ap- 
 pendages. Under favourable circumstances, at the end of a few days, 
 the bright green endochrome of these undergoes similar changes to 
 those described as presaging the production of the microgouidia, and is 
 finally formed into zoospores, which, in from twenty to forty minutes, 
 unite, within the polyhedron or large cells, into Hydrodictyon, which is 
 finally set free by a solution of the cellulose coat of the polyhedron. The 
 network thus formed differs in no essential way from that which arises 
 in the better known way, except that it is composed of much fewer cells. 
 It is generally a closed sac ; but when the polyhedron, out of which it is 
 developed, is small, it is sometimes merely an open network. Its after- 
 history appears to be identical with that of the ordinary Hydi-odictyon 
 frond." — Dr. H. 0. Wood, " American F. Water Algie." 
 
 Q 
 
38 COCCOPHYCE^. 
 
 Hydxodictyon utziculatum. Both. Bahh. Alg. 66. 
 
 Size of the families (net) variable ; also of the cells (forming 
 the meshes) and the gonidia, according to circumstances. 
 
 Eng. Flora v., p. 359. Harv. Man p. 140. Eng. Bot. (Ed. 
 2) t. 2504. Hook. Scot ii. 80. Gray. Arrang. i., p. 300. Hass. 
 Alg. 225, t. 58. 
 
 Cmfei-va reticulata, Dillw. Conf. t. 97. Eng. Bot. (Ed. 1) 
 t. 1687. Huds. Ang. ii. 596. Eelhan Cant. 444. Hull Br. 
 Fl. 331. Abbot Bedf. 275. With. vr. 132. Ray Syn. p. 59. 
 Dillen. Muse. 20, t. 4, f. 14. 
 
 In clear water. 
 
 For the development of this species see remarks nnder the genus, and 
 also an elaborate acoonnt in Braun on Kejuvenescence, pp. 137, 171, 190, 
 197, 222, and 261. Observations by Cohn " Der Mikroskopiaohen Algen 
 nnd Pilze," p. 109, and Pringsheim " Dauersohwarmer des Waaser- 
 netzes" (Berlin, 1861). 
 
 Plate XIV. fig. 1. a, " Water net," natural size ; b, one of the 
 " meshes " magnified ; c, cell with microgonidia X 300, after Cohn ; d, 
 portion of cell with angular maorogonidia X 300, after Cohn; e, free 
 macrogonidia ; /, active maorogonidia X 600. 
 
 8uh-Family 6. Ophiocytibj!. 
 
 Cells cylindrical, unaequipolar, at first short, then elongated, 
 either variously curved and contorted, sometimes circinate, one 
 or other pole attenuated into a thin, short stem, free swimming ; 
 either straight or more or less curved, collected in an umbel with 
 a simple stem, or being repeated, forming a composite umbel. 
 Cell-contents parietal, homogenous or granular, green, sometimes 
 mixed with scattered reddish or brownish globules. Propaga- 
 tion by gonidia. — Rabh. Alg. Eur. iii. 66. 
 
 Genus 27. OPHIOCTTIV»I. JVdg. (1849.) 
 
 Cells cyhndrical, at first short, then elongated, variously 
 
 curved, sometimes circinate, attenuated at one extremity into 
 
 a short, thin stem ; free swimming. Propagation by division 
 
 of cell-contents and formation of gonidia. 
 
 Bahenhorst unites the following genus with the present, giving to it 
 the characters of the sub-family, but we have preferred to follow A. 
 Braun and keep them distinct. 
 
 Ophiocjrtium cochleare. Br. Alg. Unic. p. 54. 
 
 Slender, pale green, often very long, filiform, variously curved, 
 circinate, or more or less loosely spirally involved ; stem short, 
 spine-lilce, acute or truncate ; contents homogeneous. 
 
 Size. Cells ■005-'0075 mm. diam. ; length variable. 
 
 Archer, Micr. Journ. 1866, p. 63. Rabh. Alg. iii. 67. 
 
PROTOCOOOAOB^. 39 
 
 Ophioeytium; " Science Gossip," June, 1867, p. 127, fig. 103. 
 In pools, mixed with other algae. 
 
 Plate XIV. Jig. 2. a, young cells j c, older cells ; 6, mature cell X 
 400. 
 
 Genus 28. SCIADIVM. Braun. (1855.) 
 Plant from a single individual producing a family. Thallus 
 (solitary) adnate, unicellular ; cell elongated, cylindrical, 
 straight, attenuated at the base into a slender stem. Gonidia 
 about 8, resulting from division of the cell-contents, at length 
 protruding from the ruptured apex, retained at the mouth and 
 extending in the form of an umbel, each individual becoming 
 developed into a cylindrical cell like the mother-cell. This pro- 
 cess is repeated to a third, or sometimes a fourth generation, 
 forming a composite or decomposite umbel. Ultimate cells 
 producing free biciliate zoogonidia. 
 
 The cylindrical cell of Sciadium posseasea uniformly distributed green 
 contenta, which are interrupted, in perfectly developed cells, by light 
 cross streaks, and are divided into a row of 5 to 8 about equal masses, 
 which become gonidia. I could not detect nuclei in the individual seg- 
 ments of the contents - passing into the formation of gonidia. — Brwwn, 
 'Rejuvenescence, p. 260. 
 
 Sciadium azbuscula, Braxm Unicell. Alg. p. 106, t. i. 
 
 Umbellate. Cells straight (rarely falcate), obtuse at the apex ; 
 stem about as long as the diameter of the cells. 
 
 Size. Cells "0038 mm. (rarely -007 mm.) diam. 
 
 Sciadium arhuscula, Micr. Journ., 1866, p. 4. Archer, Micr. 
 Journ. xii., 1872, p. 314. 
 
 Ophioeytium arhuscula (Br.), Rabh. Alg. Eur. iii. 68. 
 
 Attached to confervoid alg£e and aquatic plants. 
 
 Braun, writing of this species, says — " It displays an originally obovate 
 tube, generally becoming elongated into a cylindrical form, obtuse 
 above, and prolonged into a slender attached pedicel below. The con- 
 tents consist of uniformly green mucilage, in which a small vesicle 
 may sometimes be distinguished, but only in the earliest stage of growth. 
 The pedicel is transparent and colourless, and secretes at its base an 
 originally yellowish brown, afterwards dark brown mass, which gradually 
 expanda into a disc-ahaped foot. When the growth is completed the 
 green contents become divided into several masses, developing into a 
 series of 5-8 germ cells ; the cell membrane dehisces, throwing off its 
 summit as a finger-stall-shaped cover, but the germ cells, instead of 
 leaving the open tube, all collect at the point of exit with their inferior, 
 narrower, and somewhat pedioellately elongated ends sticking in the 
 tube. Thus is produced a capitule, and by the advancing growth of the 
 young family an umbel formed of individuals exactly resembling the 
 parent individual from which they originated. The emptied mother-cell 
 tube remains as the stem and support of the -umbellate family, and 
 gradually becomes filled from abovedownwards with the same yellow and 
 reddish brown secreted substance which it exhibits at its own base. The 
 
40 
 
 COCCOPHYCE^. 
 
 imperfect birth of the germ cells just described is repeated at the tran- 
 sition to the third, and mostly even to the fourth generation, so that 
 little arborescent groups are produced with twice or thrice-repeated um- 
 bellate ramification, till at length the cells which form the outermost 
 umbellules scatter out their germ cells, which, after a short swarming, 
 fix themselves again to be developed into ramified stocks of new 
 families " — Braun Rejuvenescence, p. 187. 
 
 Plate XV. a, T>, young cells ; c, commencement of the first generation 
 of daughter-cells ; d, further progress of the first generation of progeny j 
 e, second generation being evolved from the first ; /, old plant evolving a 
 third generation X 300, after Braun ; g, zoogonidia. 
 
 Sub-Family 7. Pediastee^. 
 Coenobium discoid, plane. 
 
 For other features of this sub-family see the characters of the genus, 
 which is the only one at present comprised "within it. 
 
 Genus 29. Fediastnun. Meyen. (1829.) 
 Coenobium plane, frond-like, discoid, or stellate, free swim- 
 ming, fonned of cells in a single, rarely in tbe centre in a 
 donble stratum, continuous, or with the cells here and there 
 interrupted, perforate or clathrate. Cells polygonal, central 
 entire or slightly emarginate, those of the periphery entire or 
 two-lobed, the lobes wedge-shaped, either simple or two-toothed, 
 sometimes elongated into a horn. Cell-contents green, homo- 
 geneous at first, then granular. — Mahh. Alg. Eur. iii. 69. 
 
 Formerly this genus was included in Desmidiacese, but the knowledge 
 of its life history has shown that it has no relationship with the Con- 
 jugatae. Braun illustrated the development of one species (Rejuvene- 
 scence, PI. III.), and we have reproduced some of his figures (on PI. XVI.) 
 Fig. 1 is an old disc, in great part emptied by the birth of gonidia. 
 Several of the empty cells exhibit a cross slit, through which the con- 
 tents have been discharged. The order in which this emptying took 
 place is indicated by the letters a, J, c, d, e. One cell is in the act of 
 discharging the gonidia, these having in part entered the projecting por- 
 tion of the hernia-like vesicle, formed by the swollen innermost layer of 
 the membrane of the mother-cell, in part still remaining in the internal 
 cell cavity. Three other cells still possess their perfect contents in 
 difiEerent conditions. Two of them are filled by sixteen extremely closely 
 crowded gonidia, only half of which are visible, as they form a donble 
 layer. The third nnemptied cell is in the actual transition to the forma- 
 tion of gonidia. It exhibits the first division of the contents into two 
 halves, one of which already appears halved again. Fig. 2 is a new-born 
 family immediately after the birth. The innermost layer of the mother- 
 cell has wholly emerged from the old cell, as an extremely thin vesicle, 
 enclosing the gonidia, the gonidia in the interior moving actively. Fig. 
 3 is the same family, as seen from the upper surface. Fig. 4 is the same 
 family, a quarter of an hour after birth. The gonidia, now at rest, have 
 arranged themselves in a plane disc. Fig. 5 is the surface of the same 
 family at the same stage. Fig. 6 the same family one hour afterbirth. 
 The emargination of the cells has proceeded further. Fig. 7 the same 
 again, but four hours after the gonidia ceased to move. The emargination 
 of the border-cells has passed into the formation of horns. The cells are 
 
PROTOCOCCACEJi:. 41 
 
 not even yet closely connected together, but exhibit spaces between 
 them, BO that in this stage it resembles P. pertusum. Not until the 
 second day do the cells become closely applied together ; the horns ac- 
 quire their proper shape and length at the same time. All the figures 
 are magnified 400 diameters. 
 
 The number of cells which enter into the composition of a single disc 
 vary in the same species, so that it cannot be accepted aa a character. 
 The arrangement and limit of species adopted are those proposed by 
 Brauu (" Algcvrwm wnicella/rwm," 1855). 
 
 Plate X71. figs. 1 to 7. Development of Pediastmm, after Braun ; 8 
 a, b, zoogonidia. 
 
 Section 3. diactinium. Braun. 
 
 Cells of periptery emarginate or bilobate, lobes entire. 
 
 Pediastzum selenaea. Xutz. Salh. Alg. iii. 73. 
 
 Ccenobium orbicular, entire, formed of 8-16 (rarely 31) cells. 
 Cells of periphery narrow, lunate, acutely lobed ; cells of disc 
 slightly excised, central one five-angled ; substance firm, rather 
 thick. 
 
 Size.* Ccenobium •028-"085 mm. diam. 
 
 Braun Unicell. Alg. p. 83. Ealfs Desm.t. 21, f. 5. 
 
 Pediastrum Napoleonis, Ralfs Ann. N. Hist. xiv. (1844) t. 
 12, f. 6. 
 
 Pediastrum elegans, Hassall Alg. t, 86, f. 19. 
 
 Pediastrum lunare, Hassall Alg. t. 92, f. 3. 
 
 In bogs, moor pools, &c. 
 
 Plate XVI, Jig. ^- a, 8-celIed ccenobium; J, 16-celled ccenobium X 
 400 diameters ; e, marginal cell. 
 
 Pediastrum angulosum. Ehr. Rabh. Alg. iii. 73. 
 
 Ccenobium orbicular, oblong, or subreniform, continuous, 
 composed of 8-16-32-64 cells. Cells all even, angular, those 
 of the periphery truncate at the base and dilated upwards, more 
 or less deeply notched in the middle, the lobes obliquely trun- 
 cate, outer angle very shortly apiculate, inner one ending in a 
 short horn. Central cells 5-6 angled, slightly repand in front, 
 marked with a small transverse oblong pallid spot. 
 
 Size. Ccenobium "12 mm. diam. ; cells '019 diam. 
 
 Hass. Alg. t. 86, f. 14. Ealfs Desm. t. 31, f. 11 a b. 
 Braun Unic. Alg. p. 84. 
 
 Pediasti-um Boryanum, Ralfs Ann. Nat. Hist. xiv. (1844) t. 
 12, f. 7, upper. 
 
 Pediastrum excavatum, Hassall Alg. t. 92, f. 6. 
 
 In bogs. 
 
 Plate XVI. fig. 10. a, marginal cells j b, 16-celled ccenobium ; e, 8-celled 
 ccenobium X 400 diameters. 
 
 * The size must depend on the number of cells of which the ccenobium 
 is composed ; hence throughout this genus the dimensions given must only ' 
 be accepted as approximate. 
 
42 
 
 COCCOPHYCE^. 
 
 Pediastram Botyanum. Turp. Rabh. Alg. in. 74. 
 
 Coenobium orbicular, oblong, or elliptic, variable in size, con- 
 tinuous, bright green, composed of 4-8-16-32-64 (rarely 128) 
 cells. Cells of periphery more or less deeply emarginate, or 
 two-lobed, lobes horn-like, horns colourless, short or long, 
 sti'aight, obtuse or nearly so, sometimes a little thickened ; 
 central cells very closely concrete, 4-6 angled, angular or trun- 
 cate in front, or slightly repand ; membrane decussately punc- 
 tate. 
 
 Size. Cells •02-'002 mm. transverse diam. 
 
 Braun Unic. Alg. p. 86. Ealfs Ann. Nat. Hist. xiv. (1844) 
 1. 12, f. 7, lower. Ealfs Desm. t. 31, f. 9 a. Hassall Alg. t. 
 86, f. 13. 
 
 Pediastrum hexactis, Hassall Alg. t. 92, f. 5. 
 
 Pediastrum Napoleonis, Ralfs Desm. t. 31, f. 7 a and d (short- 
 homed form) ; f. b (long-horned form). 
 
 Pediastrum simplex B. crudatum, Ralfs Desm. t. 34, f. 15 d. 
 
 Pediastrum granulatum, Braun " Rejuvenescence," pi. 3, 4 
 (English edition). Pritch. Infus. t. 1, f. 59-69. 
 
 In boggy pools. 
 
 Plate XVI. fig. 11. a, 4-celled ooenobiuin; J and e, 16-celled coeno- 
 bium; c, 32-ceUed coenobinin ; d, 8-oelled coenobixmi X 400 diameters. 
 
 var. B. gxanalatam. Etitz. 
 Cells as in the preceding, but all the cells and the horns dis- 
 tinctly granulated. 
 
 Braun tJnicel. Alg. p. 90. 
 
 Pediastrum granulatum, Ralfs Desm. t. 31, f. 8. 
 In the same localities. 
 Plate XVI. fig. 12. a, b, 8-oelled coenobia X 400 diameters. 
 
 Pediastxam 'bideatulum. Br. Unic. Alg. p. 91. 
 
 Coenobium orbicular or oblong, continuous, deep green, 
 sometimes bluish green, nearly blue, composed of 16-32 cells; 
 cells of periphery two-lobed to the middle, lobes straight, pro- 
 duced into a truncate, bidentate horn ; central cells 4-5 angled, 
 slightly repand in front. 
 
 Rabh. Alg. iii. 77. 
 
 Pediastrttm elliptieum, var. /S., Ralfs. Desm. t. 31, f. 10 a, b, c. 
 
 In boggy pools. 
 
 Distingnished by the marginal cells being divided into two obtuse 
 lobes, resembling blnnt horns, each of which is two-toothed. 
 
 Plate XMI. fig. 1. a. part of a 32.celled coenobium ; J, larger 32- 
 celled coenobium, after Balfs, X 400 diameters ; c, 16-celled coenobium ; 
 d, marginal cell. 
 
 Pediastram constzictum. Hast. t. 86, /. 15, 16. 
 
 , Coenobium orbicular, or nearly orbicular, bright green, con- 
 tinuous, smooth (?), composed of 16-32 cells ; cells of the 
 
PROTOOOCOAOBiB. 43 
 
 periphery irregularly two-lobed, sinus narrow, lobes unequal, now 
 and then constricted at the base, produced into an obtuse, rather 
 thick horn ; central cells polygonal, repand in front. 
 
 Rabh. Alg. iii. 77. 
 
 Pediastrum ellipticum, Ralfs Desm. t. 31, f. 10 d. 
 
 Pediastram Boryanum, B., Ralfs Ann. Nat. Hist. xiv. (1844) 
 f. 8. 
 
 In standing water. 
 
 Braun suspects the verity of this species, which we have never seen. 
 
 Plate XVII. fig. 2. a, 32-06lled coenobinm ; 6, 16-oelled oceaobium X 
 400 diameters, after Ealfs ; o, marginal cells. 
 
 Pediastzum gzacile, Br. JJnic. Alg. p. 93. 
 
 Cells quaternate, closely joined in a circle, centre open, 
 rarely closed ; cells deeply two-lobed, lobes ovate, produced 
 into along divergent, acuminate horn. 
 
 Rabh. Alg. iii. 75. 
 
 Pediastrum simplex, Ralfs Desm. t. 34, f. 15 a J. 
 
 In pools. 
 
 This appears to be a very rare species, at first referred to P. simplex 
 Meyen, from which it differs in the cells, being deeply two-lobed. 
 Plate XVII. fig. 3. 4-oelled coenobia X 400 diameters, after Ralfs. 
 
 Fediastzum peztusum. Eutz. Phy. Oerm. p. 143. 
 
 Coenobium orbicular, pierced with lacunae, of variable size, 
 composed of as many as 64 cells ; cells of the periphery loosely 
 connected at the base, bilobed almost to the middle ; lobes 
 straight, produced into a hyaline horn, sometimes acute, some- 
 times obtuse or truncate ; central cells more or less exactly 
 quadrangular, emarginate in front, even, with two paler spots. 
 
 Size. Perfect cells •016-'022 mm. transverse diam. 
 
 Rabh. Alg. iii. 75. Ralfs Desm. t. 31, f. 6 a, b. Braun 
 Unicell. Alg. p. 92. 
 
 Pediastrum Napoleonis, Ralfs Desm. t. 31, f. 7 c and e. 
 
 Pediastrum selencea, Kutz., Pritch. Inf. t. 1, f. 53. 
 
 In pools. 
 
 Plate XVII. fig. 4. a, J, c, 8-oelled coenobia ; d, 32icelled coenobium ; 
 e, 16-oelled coenobium. 
 
 var. 6. dathzatum. Br. Unicell, Alg. p. 93. 
 
 Disc pierced with larger openings ; central cells deeply 
 notched and bilobate. 
 
 Pediastrum cribriforme, Hassall Alg. t. 92, f. 4. 
 Plate XVII. fig. 5. 16-celled coenobium. 
 
 var. c. bzachylobum. Braun Unicell. Alg. p. 93. 
 
 Cells larger, those of the periphery emarginate or trian- 
 gularly notched, shortly two-lobed ; horns very short, truncate, 
 
44 COCCOPHTCE^. 
 
 or almost obsolete ; cells of the disc perforated 'with smaller 
 openings. 
 
 Pediastrum tricyclum, Hassall Alg. t. 92, f. 1. 
 
 Pediastrum Napoleonis, Hassall Alg. t. 92, f. 10. (?) 
 
 Plate XVII. fig. 6. a, 5-celled coenobinm ; b, 16-celled ccBnobinm, fig. 
 4 ; /, marginal cell. 
 
 Section 4. tetkactixivm- Braun. 
 
 Cells of periphery emarginate or bilobate ; lobes emargi- 
 nate, bidentate, or bifid. 
 
 Pediastmm Ehxenbezgii, Br. Babh. Alg. in., 72. 
 
 Coenobium orbicular or oblong, perfectly closed, composed of 
 8-16 cells, or quadrate, of 4 cells, which are wedge-shaped, 
 deeply lobed and arranged in the form of a cross ; cells of the 
 periphery cuneate, truncate at the base, deeply bilobate ; sinus 
 narrow, lobes obliquely truncate, more or less notched, interior 
 angles twice as long, all acute, or shortly appendiculate ; central 
 cells yellow green, polygonal, one side repand or deeply notched. 
 
 Pritch. Infus. t. 1, f. 52. 
 
 Pediastrum tetras, Kalfs Desm. t. 31, f. 1. Ealfs Ann. Nat. 
 Hist. xiv. (1844) t. 12, f. 4. Hassall Alg. t. 86, f. 17. 
 
 Pediastrum heptactis, Ralfs Ann. Nat. Hist. xiv. (1844) t. 
 12, f. 5. Ealfs Desm. t. 31, f. 2. ^^6,f. 'fe 
 
 Pediastrum simplex, Hassall Alg. fl 8 , f. 17 . 
 
 Pediastrum biradiaium, Ralfs Desm. t. 31, f. 3, 4. 
 
 In pools and boggy places. Not uncommon. 
 
 Very variable in size. The 4-celled ccenobia are often to be met 
 with, mixed with Desmids and other Algae. 
 
 Plate XVIL fig. 1. o, fonr-celled coenobia; 6, 8-ceUed caenobia; c, 
 8-ceUed coenobium of nnnsnal form, after Balfs. 
 
 var. a. truncatum. Braun Unicell. Alg. p. 97. 
 
 Lobes truncate. 
 
 Pediasti-um biradiatum, Ralfs Desm. t. 31, f. 4. 
 
 Tlate XVIII. fig. 1. b, 8-celled caenobia. 
 
 var. b. ezcisum. Braun Unicell. Alg, p. 97. 
 Lobes slightly notched, emarginate. 
 
 Plate XVIII. fig. 1. d, 4-oelled coenobium; e, 8-celled coenobium; 
 i, Ti, 16-celled coenobia. 
 
 var. c. cnspidatum. Braun Uiticell. Alg. p. 97. 
 
 Lobes deeply notched, evidently bidentate or bicuspidate. 
 Pediastrum biradiatum, Ralfs Desm. t. 31, f. 3. 
 In stagnant water, throughout Europe generally. 
 Plate XVIII. fig. 1. g, h, coenobia; /, marginal cell. 
 
PEOTOCOCCACEJS. 45 
 
 Pediasttum zotula. (Bhr.) Br.Unicell. Air/, p. iOl. 
 
 Coenobium orbicular or oblong, size and number of cells 
 variable, 4-8-16-32, pierced witb openings, bright green, even ; 
 cells of tbe periphery truncate at the base, more or less dilated 
 upwards, deeply bifid, sinus acute, lobes straight, narrow, biden- 
 tate, teeth erect or divergent, somewhat bent ; cells of the 
 centre variable in form, usually polygonal, repand, or notched, 
 containing a single paler spot, sometimes not visible, 
 
 Eabh. Alg. iii. p. 79. 
 
 Pediasti-um heptactis, Hassall Alg. t. 92, f. 9. 
 
 Pediastrum incisum, Hassall Alg. t. 92, f. 8. 
 
 In pools, &c., throughout Europe. 
 
 Plate XVIII. fig. 2. i, marginal cell j a, 4-oeIled coenobinm ; c, 
 6-oelled ccenobium ; d, 8-oelled coenobinm ; e,f, /i, 16-ceUed coenobium; 
 g, irregular coenobium. 
 
 Sub-Family 8. Sorastke^. 
 
 Cells polygonal, often shortly horned, associated in a hollow, 
 sphserical or cubical coenobinm ; cell-membrane thin ; cell- 
 contents green, homogeneous, then granular ; chlorophyllose 
 vesicle central or sublateral. Propagation by gonidia, in two 
 modes in the same species (simultaneous, or after division), 
 united into a coenobium within the mother-cell, escaping by 
 rupture of the membrane. — Rabh. Alg. Eur. iii. 79. 
 
 Genus 30. C(EI.ASTRV»I. Niig. (1849.) 
 
 Coenobium globose, hollow within, formed of a single stratum 
 
 of cells, reticulately pierced. — Eahh. Alg. Ear. iii. 79. 
 
 Frond, or family, hollow, globular, or subcubioal, composed of poly- 
 gonal or sphaerioal cells, united in one layer into a hollow olathrate net- 
 like family, the cells drawn out on the exterior into one or more lobes, 
 or simply sphaerical ; propagating by the segmentation of the cell-con- 
 tents into a definite number of portions which become arranged into a 
 hollow young frond, resembling the parent, ultimately set free by the 
 bursting of the parent cell. — Pritch. 765. 
 
 Coelastzum sphsezicum. Ncig. Ein. Alg. 97. 
 
 Coenobium globose or subglobose, composed of 4-8-16 or a 
 larger number of cells, perforated, areolae 3-4-5-6 angled ; cells 
 rounded, by mutual pressure angular, outer angles somewhat 
 conical, obtusely rounded at the apex ; interstices 5-6 angled. 
 
 Size. Coenobinm •04-'085 mm. diam. ; cells •021--023 mm. 
 
 Ccelastrum Naegelii, Eabh. Alg. iii. 79. Archer in Pritch, 
 Infus. p. 755, t. l,f. 49-55. 
 
 In boggy places. 
 
 Plate XIX. fig. 2. a, i, families magnified 400 diameters ; c, cell 
 magnified 800 ; d, cell of C. cubicum, with two obtuse processes ; e, cell 
 of Ccelastrum, perhaps C. cambrioum, with one obtuse process. 
 
 H 
 
46 COCCOPHTCE^. 
 
 Ccelastram cambxicam. Archer Micro. Journ., 1868, p. 65. 
 
 Cells rounded on the exterior margin, each bearing a single 
 truncate tubercular process. 
 . In pools. 
 
 " It was obtained by Mr. Archer on his visit to Wales, and is not re- 
 ferable to either of the remaining forms (besides C. spJitsHcum) as 
 described by Nageli, thongh perhaps showing most affinity with Otslas- 
 tmm cubiettni, but differing in each cell possessing bat one process, or 
 tubercle-like appendage, not tlu'ee. These likewise showed varioas con- 
 ditions of the growth of the younir ccenobla within the mother-cells from 
 the earliest stage, the most minute of which showed the full character 
 of the cells, each with the truncate tubercle-like process." — Qitart. 
 Journ. Micro. Soc, I.e. 
 
 Coelastrum miczospomm. (Nag-) Braun Alg. Vnic. p. 70. 
 
 Cells 8-1 6 or 32, exactly sphserical, containing a single globule ; 
 interstices small. 
 
 Size. Ccenobium -04 mm. diam. ; cells -009 mm. diam. 
 Micr. Journ., 1868, p. 65. Pritchard's Infus. f. 755. 
 In bogs and pools. 
 
 " The group (ccenobium) is formed of rather large cells, externally 
 globularly rounded, their margins, where in mutual contact, being 
 straight, and leaving at the angles exceedingly minute, somewhat tri- 
 angular interspaces, like very minute pores, leading into the central 
 cavity chai-acteristio of the forms appertaining to this genns." — Archer. 
 
 Genus 31. ST&UR06ENIA. Kutz. 
 
 Ccenobium cubical, hollow within, formed of 4-8-16 quad- 
 rate or sub-quadrate cells. Propagation by quiescent gonidia, 
 produced after the subdivision of the cell-contents. — Rah. Alg. 
 Eur. iii. 80. 
 
 Crucigenia, Morren in Ann. des Sci. Nat., 1830, t. 20, p. 
 404. 
 
 Stauzogenia zectangulazis. Braun Alg. XInic. p. 70. 
 
 Cells oblong-oval, 4-16-64, associated in tabular families, 
 almost twice as long as broad, angles obtusely rounded. 
 Size. Cells -0075 x -004 mm. 
 Archer in Quart. Journ. Micr. Sci., 1875, p. 206. 
 In pools. 
 Flate XFin. fig. 3. o, families X 400 ; 6, magnified 800. 
 
 Genus 32. SORASTRUM. Kutz. (1845.) 
 Ccenobium globose, solid within, free swimming, formed of 
 4-8-16-32 compressed wedge-shaped cells, which are sinuate, 
 emarginate, or bifid at the apex, and radiately disposed. Pro- 
 pagation unknown. — Rabh. Alg. Eur. iii. 81. 
 
PROTOCOCCACE^. 47 
 
 The family (or oceuobiam) in this genua is solid, and not hollow as in 
 Ccelastrum, composed of wedge-shaped or heart-shaped cells, somewhat 
 compressed and united into globose families, the narrow ends meeting 
 in the centre, with the outer margin emarginate or divided. 
 
 Sozastxum spinulosum. Nag. Eim. Alg.p. 99, 
 
 Coenobiiim spiuulose, cells wedge-shaped, apex slightly 
 emarginate, angles obtusely rounded, bi-spinulose. 
 
 Size. Cceuobium to "04 mm. diam. 
 
 Archer Micr. Journ., 1866, p. 124. Pritch. Infus. t. I, f. 
 56-58. Rabh. Alg. iii. 81. Reinsch Algenflor. p. 86, t. 5, f. 6. 
 
 In stagnant water. 
 
 Plate XIX. fig. 1. a, i, families magnified 400 diameters ; c, side 
 view of cell ; d, front view of same. 
 
 Genus 33. SELENASTRUK. Reinsch. 
 Cells semilunate, joined together by the middle of the convex 
 margin, in families of 4-8, regularly disposed. Propagation 
 unknown. — Reinsch Algenflor. Franh.p. 64. 
 
 Selenastzum Bibxaianum. Reinsch Algenflora p. 64. 
 
 Cells semilunate, with the cusps either expanded or curved 
 inwards ; minor families constituted of four cells in pairs, major 
 families of these combined in more or less sphajrical masses. 
 
 Size. Cells •016--023 mm. long X ■005--008 mm. diam.; 
 minor families •023-'031 mm. diam. 
 
 In moor pools. 
 
 Plate XIX. Jig. 3. a, families magnified 400 diameters ; b, pair of 
 cells magnified 1000 diameters. 
 
 8uh-Faviily 9. Ohaeaoie^. 
 
 Cells always innate, often distinctly stipitate, variable in 
 form ; cell-membrane delicate, growing thicker with age (then 
 double membrane visible) ; cell-contents bright green, homo- 
 genous, afterwards always graaular, with one starch granule, 
 ultimately divided. Propagation by repeated binary division of 
 the cytioplasm, resulting in more or less numerous biciliate zoo- 
 gonidia. — Rabh. Alg. Eur. iii. 81. 
 
 Genus 34. CHARACIURI. Braun. (1847.) 
 Cells oblong, ovate, pyriform, fusiform, rarely acicular or 
 subglobose, equal or oblique, erect or inclined, attenuated at 
 the base in a hyaline stem. Cell-contents green, homogenous 
 or granular, zoogonidia, succeeding division of the cytioplasm, 
 more or less numerous, occupying the whole of the cell, at 
 length greatly agitated, escaping by a lateral (rarely terminal) 
 rupture, oblong, with two vibratile cilia. — Braun Unioel. Alg. 
 p. 29. 
 
48 
 
 COCCOPHYCB^. 
 
 Characium Sieboldi. Br. Alg. Urdc. 32 t. 3, /. A. 1-21 . 
 
 Cells erect, equal, at the beginning nearly lanceolate, when 
 older pyriform or obovate, 2-3-4 times longer than broad, apex 
 obtuse or broadly rounded ; stem short, hyaline, base attenu- 
 ated, truncate, not discoid ; contents bright green or yellowish- 
 green, granular, in the beginning with a single amylaceous 
 granule, afterwards with several. 
 
 Size. Cells •022--026 mm. diam. 
 
 Eabh. Alg. iii. 83. 
 
 In clear water, attached to filiform algse. Bangor {W. 
 Joshua) . 
 
 " The gonidia of this species exhibit, after they have already attached 
 themselves by their ciliated extremities, a tremulous motion lasting tor 
 almost a quarter of an hour, and evidently commencing in the delicate 
 stalk." — Braun p. 230. 
 
 Plate XX. Jiff. 9. Cells in various stages, in situ, X 400 ; 10, cells 
 containing mature zoogonidia ; 11, free zoogonidia. 
 
 Chazacium oznithocephalum . Sr. Alg. Unic. p. 42, t. 3 C. 
 
 Cells from the beginning unequal, incurved, distinctly stipi- 
 tate, afterwards one side swollen, semilunate, apex produced 
 into a straight or inclined beak ; stem elongated, slender, base 
 sometimes discoid ; cell-contents bright greeu, granular, with a 
 central or lateral starch granule. 
 
 Size. Cells •025-"033 mm. long, without stem, half as wide, 
 or more. 
 
 Micr. Journ., 1867, p. 85. Eabh. Alg. iii. 86. 
 
 In pools. 
 
 Plate XIX. Jig. 5. a, young cells ; d, cell further advanced ; J, c, f, 
 mature cells in different stages of division ; e, mature cells with en- 
 doohrome artificially contracted, all magnified 600 diameters. 
 
 Chaxaciuni tenue. Eerm. in Bahli. Beitr. p. 26. 
 
 Cells erect, narrowly lanceolate, six times as long as broad, 
 attenuated towards each extremity, somewhat rostrate, and 
 hyaline above ; stem short, slender, not dilated at the base ; 
 contents homogenous, bright green. 
 
 Size. Cells •003--006 mm. diam. 
 
 Micr. Journ., 1866, p. 126, 193. 
 
 Characium ambiguum, var. c, Rabh. Alg. iii. 87. 
 
 Attached to filamentous algas. 
 
 Plate XI^.fig. 4. Cells magnified 400 diameters. 
 
 Genvs 35. HYDRIANVAI. Bdbh. (1864.) 
 Cells as in Characium, but cell-contents at the beginning 
 homogenous, afterwards contracted into a dark green ovoid 
 corpuscle, from which, by oblique division, 2-4-8 biciliate zoo- 
 gonidia are produced, which escape by a terminal aperture, — 
 Ralih. Alg. Eur. iii. 87. 
 
PEOTOCOCCACBJE. 49 
 
 Hydzianum hetexomoiphum. Reinsch contrib. p. 80. 
 
 Cells at first globose-elliptical, attenuated below into a thin 
 hyaline stem ; contents granular, then contracted in prepara- 
 tion for formation of the gonidia ; zoogonidia elongated, escaping 
 at the broadly opened apex. 
 
 Size. Cells, unopened, •008-'0095 mm. broad ; opened 
 cells -0066 X -02 mm. 
 
 Reinsch Contributiones ad Algologiam (1874) p. 80, t. 11, 
 fig. 3. 
 
 Attached to filamentous algse. 
 
 JPlate XIX. Jig. 6. a, cells in difPerent stages attached to a filamentous 
 alga magnified 400 diameters ; i>, yonng cells ; i;, matare cells magnified 
 800 i d, cell with zoogonidia escaping, and magnified 1200 diameters ; e, 
 zoogonidia farther magnified. 
 
 GE.NUS 36. CODIOLUia. Smwn. (1862.) 
 Cells at first obovate, as they grow older becoming clavate, 
 or nearly cylindrical, densely aggregated in tufts, base attenuated 
 into a stem ; cell-contents green, delicately granular, mixed 
 with numerous starch granules. Propagation by zoogonidia, 
 and also by resting spores (hypnospores). — Braun Unic. Alg. 
 ■p. 19. 
 
 Codiolum gregaiium. Br. Alg. Unic. p. 20. 
 
 Cells elongated, subclavate, green ; many times longer than 
 the diameter, apex rounded. 
 Size. Cells '03 mm. diam. 
 Eabh. Alg. iii. 90. 
 
 On maritime rocks (ifJ. M. Holmes). Also in the drip of 
 fresh water. 
 
 Some persons contend that this is only a marine plant, others that it 
 ooonrs also in the neighbourhood of the coast, but either in sestuaries 
 or entirely removed from salt water. We include it here without preju- 
 dice to either opinion. 
 
 Plate XX. Jig. 1, 2, 3, young plants ; 4, 5, further developed plants ; 
 6, mature plants X 300 diameters, one containing starch granules, the 
 other mature zoogonidia ; 7, 8, zoogonidia. 
 
50 COCCOPHYCE^. 
 
 Family III. VOLVOCINE^. 
 
 Coenobia mobile, globose, subglobose, or quadrangular and 
 flattened, produced from agile biciliate green cells, with a double 
 contractile vesicle. Common tegument of the coenobium hya- 
 line, more or less ample. 
 
 Propagation sexual or asexual. The sexual monaecoius or 
 disecious, either all or some of the cells of the coenobium ex- 
 hibiting male and female characters. Male cells containing 
 spermatozoids (aniheridia), the female finally changed into a 
 quiet oospore. Non-sexual propagation by means of motile 
 gonidia (macrogonidia and microgonidia) . These arise from the 
 simultaneous and repeated division of the cell contents (cyii'o- 
 plasm). Macrogonidia definite in number (2, 4, 8, 16, &c.), 
 the larger oblong or rounded, with the anterior extremity more 
 or less rostellate, with two cilia exserted through the membrane 
 of the vesicle, furnished with a parietal red spot {eye-spot), and 
 often two contractile vacuoles. Microgonidia indefinite in 
 number, much smaller, pale or dull green, or yellowish, with 
 cilia at the apex, mostly even within the mother-cell, endued 
 with rapid motion, and ultimately escaping by rupture of the 
 membrane. 
 
 Pritchard's " Infxisoria " (p. 144) may be consnlted with advan- 
 tage, althongh including some genera which undoubtedly belong to 
 Infusoria. Also the various memoirs hereafter referred to under the 
 several genera. 
 
 The passage into amasboid conditions has been observed in several 
 genera, but this is a subject on which further investigation is needed. 
 T. G. White has seen it in Chlamydococeus (" Journ. Qnekett Micr. 
 Club," 1879), Archer in Stephanosphesra (" Quart. Journ. Micr. Sci.," 
 1865, p. 127), and Dr. Hicks in Volvox (" Quart. Journ. Micr. Sci.," 
 1860, p,99, and 1862, p. 96). 
 
 Genus 37. CHI.AniTDOCOCCnS. Br. (1849.) 
 
 Cells globose, or subglobose, (4-8 joined in a very fugitive 
 coenobium), cell-membrane thickish, firm, cell contents granular, 
 brownish red or vermilion, in certain stages changing into green. 
 Macrogonidia 2-4-8 rounded, the frontal extremity bearing 
 very long cilia, and furnished with a central reddish nucleus 
 and four to six starch granules (not always visible) involved in 
 a very ample, hyaline, mostly ovoid tegument. Microgonidia 
 much smaller, numerous, yellowish or dull green, the apex 
 reddish, biciliate, moving actively within the mother cell, and 
 at last escaping, by rupture of the membrane. 
 
VOLVOCINE^. 51 
 
 Chlamydococcus pluvialis. Br. Rejuvenesoenoe, p. 20S. 
 
 Cells_subglobose, very variable in size, brownish red, chang- 
 ing in some conditions to green. 
 
 Size. Cells •007--035 mm. 
 
 Rabh. Alg. Eur. .iii, 93. Cohn Nova Acta. xxii. p. 749, 
 t. 67 A. B. Pritchard Infus. 523, t. xix. f. 20-81. T. C. 
 White, in " Quekett Microscopical Journ.," vi. p. 43. 
 
 Hcematococcus pluvialis. Flotow, Nova Acta xx. 
 
 Hcmnatococcus Corda. Meneg. Nost. p. 20, t. 1, f. 5. 
 
 Hcematococcus mucosus. Morren Rubefact : des Eaux, t. 6, 
 f. 10-20. 
 
 Protococcus pluvialis. Kutz. Tab. i. f. 1. Cohn, Memoir 
 on Protococcus. 
 
 Protococcus monospermus. Corda, in Sturm Flora ii. 25. 
 
 On rocks, stones, &c., in hollows filled with rain water. 
 
 " Normally fully deyeloped oells of thia mnltiform creature, sometimes 
 like a plant, sometimes like an animal, present the appearance of glo- 
 bules from '02 to '04 mm. diam., with a thick, tough cell membrane, and 
 granular-punctate, opaque contents, sometimes of a brown, sometimes (at 
 other periods, or in other localities) bright red colour. In the mass of 
 the dark contents lie hidden several other structures, which at this period 
 are completely concealed, namely 4-6 starch globules of "0033 or at 
 most "005 mm. in diameter, in which, as in those of Hydrodiotyon, a 
 nucleus and an envelope may be distinguished, acquiring a violet colour 
 with iodine, the nucleus becoming rather redder. Sulphuric acid causes 
 a considerable swelling up of the coat. There also appears to exist in 
 the centre of the cell a large, very delicate nuclear vesicle, which, how- 
 ever, is so covered up by the rest of the cell contents, that it can only 
 be very indistinctly perceived, and cannot even be clearly displayed 
 when the contents are squeezed out. When these resting globular cells 
 are placed in water they give birth to four gonidium-like swarming 
 cells. Even before the commencement of the division of the contents 
 by which the latter are formed, a change begins in the colour of the 
 parent cell, the red colour retreating to some extent from the periphery, 
 and a yellow (sometimes rather greenish) border forming round the deep 
 red inner mass. The young swarmers also, for a short time after they 
 issue out, have only a narrow yellow rim round a, dark red middle. 
 During the two or three days' period of movement and growth of these 
 swarming cells — in which they grow to about four times the original 
 size, changing their obtusely ovate form at the same time to a reversed 
 , pear-shaped apiculated shape — important new changes take place in the 
 contents of the cells. The red colour becomes more and more concen- 
 trated into the middle of the cell, so that a sharply defined bright 'red 
 nucleus is formed, in the interior of which a lighter space is often 
 clearly perceptible, corresponding to the nuclear vesicle above-men- 
 tioned, around which the red colouring matter forms a covering, mostly 
 complete, but sometimes imperfect and interrupted. The rest of the 
 cell contents have become a brilliant green, and in them may be clearly 
 distinguished the above-mentioned starch granules, as well as many 
 more smaller green granules. The ciliated point of the cell, often 
 drawn out like a beak, is colourless. This first moving generation is 
 succeeded by a not yet accurately determined number of similar active 
 generations populating the water for some weeks, and often giving it a 
 bright green colour, till at length universal rest recommences, and the 
 
52 COCCOPHTCE^. 
 
 cells sink to the bottom, or attach themselves to the sides. The transi- 
 tion from one active generation to another takes place throngh a transi- 
 tory resting generation of extremely short duration. The fall-grown 
 swarming cells finally come to rest -within their wide shirt-like envelope, 
 and almost simnltaneonsly divide into two cells, which, withont becom- 
 ing active, divide again into two cells. Thus within the mother enve- 
 lope are produced fonr daughter-cells (more properly grand-children), 
 which begin to move soon after they ai-e completely formed, and, tearing 
 open the delicate enveloping vesicle, part company. The whole of this 
 process of development is gone throngh very rapidly, being completed 
 in one night and the succeeding morning. The second active generation, 
 thus formed, resembles the first, with the single distinction that the 
 active cells arc green from the first, and have a smaller red nucleus in 
 the interior. The subsequent active generations bear a general resem- 
 blance to the preceding, but many modifications present themselves. 
 Thus, for example, we not unfrequently see the full-grown swarm-cells 
 assume strange two-lobed, or even four-lobed, shapes, beginning to 
 divide before they come to rest ; or sometimes a transverse constriction 
 and bisection of the cell takes place, caused by a partial protrusion of 
 it from the loose shirt, &c. The formation of vacuoles is a pretty con- 
 stant phenomenon in the later active generations, and there may be 
 several of them eccentrically placed, with the red nucleus retaining its 
 central position, or a single central vacuole, causing a lateral displace- 
 ment of the red nucleus. This red nucleus often becomes very small 
 in the last generations, so that it very much resembles, especially when 
 rendered parietal by the formation of a central vacuole, the red cor- 
 puscle occurring in the gonidia of many genera of Algae belonging to 
 very diverse families, and which was called the • eye ' in the Volvo- 
 cinea by Ehrenberg. 
 
 " A total disappearance of the red colour not unfrequently occurs. 
 In the later stages of the cycle of generations arrives, finally, the for- 
 mation of microgonidia ; many individuals, instead of producing four 
 daughter-cells, undei^ further division, so as to give birth to a brood 
 of 16 or 32 minute cells, which, before they separate, form a mulberry- 
 like body, but separating at length, commence a very active swarming 
 inside the parent envelope, terminating in the rupture of this coat and 
 the rapid dispersion of the little ' swarmers.' These are of longer 
 shape than the large ' swarmers,' only about "0066, rarely "01 mm. long, 
 of yellowish or dirty yellowish green colour, with reddish ciliated 
 points. They do not exhibit increase of size, like the large ' swarmers,' 
 never become coated with a perceptible and loose membrane, and have 
 no further power of propagation. Most of them die after they have 
 settled to rest, dissolving away ; others turn into little red globules, and 
 it is doubtful whether they can grow up to the normal size. If we now 
 further examine how the cycle of active generations is closed and 
 carried over to the resting vegetation, we find that the large ' swarmers ' 
 of the last active generation, when their growth is completed and they 
 have attained the stage of rest, instead of dividing again remain un- 
 divided, assume a perfectly globular form, and in the course of a few 
 days become clothed by a thick, closely applied cell membrane, while 
 the earlier loose distant membrane gradually disappears. The contents, 
 which at the commencement of the rest were all green, except the little 
 red nucleus, or even often entirely green, now gradually become red 
 again, passing from green through many tints of brown, or of brilliant 
 golden green and golden brown, into red. These globular, thick-coated 
 cells (the same as those with which we began) behave like seed.«ell8 
 or spores, passing into a state of perfect vest. They do not exhibit any 
 growth, and after the membrane has attained its proper thickness, and 
 
V0LV0CINBJ5. 53 
 
 the oontenta their red colour, no further visible alteration takes place 
 so long as they are kept in water. A desaication must take place before 
 a new cycle of generations can begin. Perfectly dry specimens placed 
 again in water ordinarily produce active gonidia the next morning. 
 Original specimens obtained in 1841 had retained their vital force during 
 a preservation of seven years in a herbarium. 
 
 " In order to complete the maia features of the picture of the alter- 
 nating generations of this maltiform creature, I must notice that, in 
 addition to the described active generations (maorogonidia and micro- 
 gonidia) and the concluding generation, passing into the spore-like con- 
 dition of rest, there are other generations which, as compared with the 
 gonidinm-like and spore-like conditions, must be regarded as the proper 
 representatives of the vegetative development. These are generations 
 endowed with quiet and slow vegetative growth, which multiply by pure 
 vegetative division, unaccompanied by any swarming movement. It 
 depends solely upon external conditions whether the resting cells, which 
 are here characterized as seed -cells (spores), at once give rise to the new 
 active generations, or to a series of quietly vegetating generations of 
 cells. The former is the case when the seed-cells are totally immersed 
 in water, the latter when they occur on a spot which is at once damp 
 and exposed to the air, as is the case in the native condition, especially 
 in the milder intervals of winter, and in the damp season of. approaching 
 spring, bnt temporarily also at all other seasons, on the margins of the 
 little basins inhabited by Chlamydococcus, as often as they are filled by 
 showers of rain. In cultivation in the house these vegetative genera- 
 tions are rarely observed, while in their native stations they certainly 
 occupy the most important place in the alternations of the various con- 
 ditions of life, as may be concluded from the thickness of the crusts 
 and membranes formed by such vegetative multiplication. The forma- 
 tion and multiplication of these vegetative generations also take place 
 by the division of the cell contents, either by simple division, the first 
 generation being transitory, or by double halving (apparently quarter- 
 ing). But the newly formed cells do not slip out, like the young 
 ' svvaroiers,* from the mother envelope ; they remain in the same place 
 and position. The membrane of the mother-cell appears to become 
 softened, expands, and becomes gradually drawn out to nothing, rather 
 than regularly burst open ; it at length vanishes in some undistingulsh- 
 able way, the daughter-cells meanwhile acquiring a tolerably thiolr, 
 closely applied cell membrane of their own. The division is repeated 
 many times in this way, and as the cells all remain in intimate contact, 
 first small families, but by degrees large conglomerates of cells are pro- 
 duced. The size of the single cells in these groups varies from "01 to 
 •02 mm. *, their shape is not truly globular, but partly bounded by flat 
 surfaces, as results from the alternating divisions, according to the three 
 directions of space. Ordinarily the colour is light brown. If ignorant 
 of the rest of its history, one would be led by the form and mode of 
 division of the cells to regard these crusts as belonging to a Plev/ro- 
 coccus. In the same crusts occur isolated large cells, loosened from 
 their connection with the others, perfectly globular in form, and appear- 
 ing to divide no more, but to have passed again into the condition of 
 resting spore cells. Tney are distinguished from the rest by their 
 darker contents and thicker cell membrane. Probably the return of 
 these to renewed resting vegetation takes place by a passage through 
 the series of active generations. Every shower of rain will wash away 
 these loose ripe cells of the crusts of Ohlamydococcus ; carried into 
 collections of rain water, they will soon produce the active brood, which, 
 returning to rest after a few active generations, settles on the margins 
 of the little puddles, and then recurs to the resting mode of vegetative 
 nmltiplication." 
 
 I 
 
54 
 
 COCCOPHYCE^. 
 
 The foregoing life-history is somewhat abridged from the acoonnt 
 given by Braun (" Rejnveuescenoe," pp. 206-214), and for farther de- 
 tails the reader is referred to the .Memoir by Flotow ("Nova Acta 
 Natura Curiosorum," Vol. xx. p. II), and that by Oohn (translated in 
 " Memoirs " by the Hay Society, 1853), which will furnish all that can 
 be reqnired, and are really exhaustive. For remarks on an Amaeboid 
 condition see paper by T. Charters White in the " Journal of the 
 Quekett Microscopical Club " for 1879. 
 
 Plate XXI. Jig. 1. a, still cells X 400 ; 6, green cell with chloro- 
 phyll vesicle, and reddish nnclens ; c, a cell which had been dried six 
 years, undergoing segmentation after revival ; d, completed division j 
 e, division into four ; /, naked green zoospore ; g, encysted zoospore ; 
 h, primordial cell, commencing division in two ; t, encysted zoospore, 
 which has deliquesced ; J, primordial cell dividing in four ; A-, encysted 
 zoospore in still condition ; I, division of still cell into 8 cylindrical 
 zoospores; m, escaped zoospore; «-, division of encysted cell into 4; 
 0, division into 8 ; p, division into 32 ; g, zoospores from the latter form 
 escaped from mother-cell ; r, large red still cell dividing into segments ; 
 s, red encysted cell ; t, yellow-green still cell. All after Cohn. 
 
 Chlamydococcus nivalis. Br. Rejuv.p. 206. 
 
 Cells globose, red, at first with a hyaline border, which is the 
 thickened epispore, which gradually disappears with age. 
 
 Size. Cells •01-'03 mm. diam. 
 
 Eab. Alg. Eur. iii. 93. 
 
 Hcematococcus nivalis, Ag Icon. Alg. t. 31. 
 
 JProtococcus nivalis, Ag. Supp. p. 13. Hook. Eng. Fl. v. 
 p. 395. Mackay Hibern. p. 246. Hass. Alg. p. 335, t. 83, f. 2. 
 Harv. Man. p. 182. Grev. Sc. Crypt. Fl. t. 231. 
 
 Palmella nivalis. Hook, in Parry's Voy. App. p. 328. 
 
 Tremella nivalis. Brown, in Ross Voy. Supp. p. 44. 
 
 Uredo nivalis, Bauer. Journ. Sci. and Art vii. p. 222, t. 6. 
 
 On snow and wet rocks, &c. 
 
 Probably not specifically distinct from CKLd^nydoeoccus 'pluvialis. For 
 the history of this minute plant, long known as " Red Snow," consult 
 " GrevUle's Scottish Cryptogamic Flora," Vol. iv. plate 231. The inter- 
 esting observations by Agardh and others, there detailed, are too long 
 for quotation here. 
 
 Introduced to the notice of botanists in this country on the return of 
 Capt. Boss from Baffin's Bay, where it was fonnd extending for some 
 miles, it was regarded by Bauer as a fungus, by Robert Brown as an 
 Alga, and by Baron Wrangel as a Lichen. Agardh first included it in 
 Algae, under the name of Protococcus nivalis. 
 
 It has been found in this country " on the borders of the lakes of 
 Lismore, spreading abundantly over the decayed reeds, leaves, Ac, at 
 the water's edge, but in greater perfection on the calcareous rocks within 
 the reach of occasional inundation, more or less perfect at all seasons of 
 the year." — Carm. Also in Ireland. 
 
 Plate XXI. Jig. 2. a, still cells X 400 ; 6, cell divided in two ; o, cell 
 divided in four ; d, advanced stage of subdivision in four ; «, encysted 
 zoospore ; /, free zoospore ; g, resting cell. 
 
VOLVOCINB^. 55 
 
 Geiius 38. CHLAiaTDOMONAS. Ehrh (1833.) 
 
 Macrogonidia ovate or oblong-rounded, green, delicately 
 granulated, involved in a rather narrow hyaline tegument 
 frontal extremity very obtuse, or somewhat truncate, with a 
 contractile vacuole, and two cilia ; posterior extremity with a 
 large chlorophyllose vesicle, and with or without a red lateral 
 spot. Micvogonidia arising from repeated division of the oytio- 
 plasm of the macrogonidia, oblong or ovate, numerous, pale 
 green or yellow, becoming brownish. Tranquil oospores glo- 
 bose, red or brownish, contents firm, colourless, hyaline. 
 
 " Chlamydomonas is distingnished from Chlamydococcus by the closely 
 applied membrane (not standing away from the contents) of the old 
 swarming cells, also by the absence of the little starch-vesicles in the 
 interior, while, however, as is nsual in most of the FalmeilacecBf a single 
 large ' chlorophyll utricle ' (starch utricle ?) exists in the interior. 
 There is no central red nucleus, as in the gonidia of Chlamydococcus, 
 but some species have a parietal red spot. The motion is affected by 
 two cilia, as in Chlamydococcus. As in that genus, there is a growth of 
 the gonidia during" ' swarming,' which lasts over the day and night. 
 There is also a formation of miorogonidia. The species of this genus 
 are doubtless very numerous, but the distinction of them among them- 
 selves, as "well as from the swarming cells of many other Algae, is very 
 difficult without a complete acquaintance with the history of their lives. 
 The species Chi. oitv/a, occurs in the Ehine valley, near Freiburg, in 
 sand pits, which are occasionally almost completely dried up in summer. 
 The macrogonidia grow during their period of swarming from -OIB to 
 almost "033 mm. long ; they are longish, of equal diameter on both 
 sides, and verj obtuse, almost truncated, having a colourless place at the 
 ciliated extremity, presenting the form of a notch. In regard to other 
 points, the contents are dark green, finely granular, with a large vesicle 
 at the posterior extremity, a roundish lighter space in front of this, and 
 no red point. They multiply by simple or double halving in several 
 successive generations. Sometimes a further continuation of the divi- 
 sion of the full-grown macrogonidia occurs, forming sixteen or thirty- 
 two macrogonidia from '005 to '008 mm. long, of ovate shape and 
 lighter colour, tending towards brownish yellow. The resting cells are 
 globular, abont '025 mm. in diameter, at first green, subsequently light 
 vellowish brown, finally flesh-red ; they have a tough, colourless, and 
 transparent membrane. Another species. Old, tingens, occurs in enor. 
 mous quantity in the puddles of the sandstone quarries at Lorettoberg, 
 near Freiburg, in the month of March, in mild seasons sometimes even 
 in January and February. The swarming cells are smaller than in the 
 preceding, '008 to '016 mm. long, ovate, lighter green, likewise destitute 
 of a red spot, and the membrane is more distinct in the old age. In- 
 crease by double, rarely by simple halving, in the former case with de- 
 cussating sections. 
 
 " Several species of this genus, previously included in the animal 
 kingdom, but nearly allied to Olwococcus and Chlamydococcus, present 
 themselves in the beginning of spring, in such abundance that they 
 produce a striking green colouration of the water ; a few weeks later 
 they vanish, leaving no trace, and are not noticed again throaghont the 
 whole vear." — Bratm Bejwienescence, p. 215. 
 
56 COCCOPHYCE^. 
 
 Chlamydomonas pulvisculus. Ukr, Tnfus. p. 6i. 
 
 Macrogonidia ovate, twice as long as broad, or nearly ; deep 
 green, with a bright red lateral spot. 
 
 Size. Diam. •0065--013 mm. 
 
 Eabh. Alg. Eur. iii. 94. Cohn in Nova Acta. xxiv. t. 18, f. 
 28. Fresenius Beitr. 235, t. 11, f. 43-45. Pritchard Infus. 
 521, t. 18, f. 40, 51-54. 
 
 Diselmis viridis, Dujard. Zoophy. 342 iii. f. 20, 21. 
 
 In stagnant water. 
 
 " These creatures form a large portion of the green matter which 
 colonrs the water contained in water-bntts, ponds, and puddles in the 
 summer and autumn, especially after a storm. Whenever these exist in 
 large quantities, multitudes of them, and of their envelopes, rise to the 
 surface of the water, and form a green stratum upon it." — Pritchard. 
 
 Plate XXI. fig. 3. a, swarmspore; 6, c, encysted and undergoing 
 division ; d to g, gloeocystis forms ; /*, resting cells, after Cienkowski X 
 400 ; t, stellate cyst, from Stein ; j, individual differentiated ; A, swarm- 
 ing X 600. 
 
 Genus 39. VOLVOX. fAnn. (1758.) 
 Coenobium sphserical, continually rotating and moving, look- 
 ing like a hollow globe, composed of very numerous cells 
 arranged on the periphery at regular distances, connectedly 
 the matrical gelatin ; furnished with a red lateral spot, two 
 contractile vacuoles, and two long exsei'ted cilia, all circum- 
 scribed within a common hyaline vesicle. Propagation sexual 
 or non-sexual. In the non-sexual certain distant cells greatly 
 enlarge, divide into numerous parts, and evolve daughter- 
 coenobia within the parent-ccenobia, which are ultimately set 
 free. In sexual propagation certain masculine cells undergo a 
 multipartite division into fascicles of mobile spermatozoids 
 which are contractile, pear-shaped, and biciliate, afterwards 
 free. The female cells are enlarged, but do not undergo 
 division ; after fertilization they develop into motionless 
 oospores, which are finally red, surrounded by a double epi- 
 spore. 
 
 The following is a, summary of the structure and life-history, of 
 Tolvox as given by A. W. Wills in the " Midland Naturalist '' 
 (Sept.-Oct., 1880) :— 
 
 " It seems hardly necessary to describe the nonnal aspect of this 
 organism . Briefly, under a low power, it is seen to consist of a spfaserical 
 globe of mathematical perfectness, so transparent that, as it glides 
 along, any object over which it passes is clearly visible through its 
 vacant spaces, i.e., through such parts as are not occupied by the struc- 
 tures presently to be noticed, while by focussing the binocular on the 
 
VOLVOCINEiE. 57 
 
 lower half of the plant the effect is obtained of looking into the inside 
 of a glass sphere of crystalline purity and of absolute symmetry. The 
 diameter of a full-grown Volvox is usually about 1-60", and individuals 
 are to be found in each colony varying from this down to about 1-80". 
 The iriner surface of the sphere is studded at intervals with dark green 
 points, not disposed irregularly, but so arranged that each is usually the 
 centre of a group of six others, placed at the extremity of nearly equal 
 radii. These green points are ' gonidia' each probably endowed with 
 the potentiality of becoming » perfect Volvox, though only a certain 
 number of them actually undergo that sequence of changes which 
 results in their becoming fresh individuals resembling the parent 
 sphere. 
 
 " Each gonidium is either sphserioal or pyriform (in which case its 
 pointed end is directed outwards), and contains, in its early stages at 
 any rate, one or more contractile vacuoles disposed among a mass of 
 granular endochrome, and stated by Busk to pulsate rhythmically once 
 in about forty seconds. (Plate 23, Fig. 6.) 
 
 " At this period are also to be seen in the body of the gonidium one, 
 two, or three — occasionally even more — brilliant colourless spots, from 
 one of which is probably derived a nucleus which can be detected by the 
 use of reagents at a later period. 
 
 " There is also often lodged within the substance of the zoospore a 
 brown or red ' eye-spot,' and all the eye-spots in an individual look, so to 
 speak, one way. 
 
 " The apex of each gonidium is more or less produced into a trans- 
 parent point, from which proceed two cilia several times as long as the 
 gonidium itself, which pass through two minute pores in the outer cell 
 wall, and move freely in the surrounding water. I am fortunate in 
 having mounted a specimen of Volvox, in which these pairs of foramina, 
 are clearly shown, and the regularity of their disposition at a uniform 
 angle to the equator of the sphere is striking. (Plate 23, Fig. 7.) It is, 
 of course, by the combined action of these numerous pairs of cilia that 
 the whole organism progresses. Of the direction of the resultant 
 motion we shall speak shortly. 
 
 " Viewing the surface of the sphere with its convexity presented to 
 the objective, we find, by very careful adjustment of light, that from 
 each gonidium there runs to each of the six surrounding ones a fine 
 thread, sometimes double, occasionally triple, always of extreme tenuity 
 (Plate 22, Figs. 1 and 3), of mich tenuity, indeed, as to be frequently 
 invisible ; but as the use of certain reagents often brings these lines 
 into view where it had been previously impossible to detect them, and 
 as they may be sometimes discerned for an instant when the eye is 
 applied fresh and unfatigued to the microscope where even a moment 
 later they seem to be absent, it may be assumed that the structure is 
 universal, though often far too subtle to be detected. It is needless to 
 say that no skill of the draughtsman can even suggest its infinite deli- 
 cacy, while the figures given in books, not excepting the beautiful 
 drawings in Ehrenberg's ' Infusionsthierchen,' exaggeiate the strength 
 of the connecting lines to the extent of grossly caricaturing the extreme 
 fineness of Nature's own handiwork. 
 
 " To return to the gonidia and their history. A certain number of 
 these in each individual are selected to produce a group of young Vol- 
 voces within the parent sphere. The books fix this number as usually 
 four or eight ; but out of twenty.five individuals now in the field of my 
 microscope I find only three containing four incipient spheres of the 
 second generation, while only one contains eight, and there are four 
 containing five, six with six, ten with seven, and one with nine such 
 progeny. Almost every Volvox, when first discharged from the parent 
 
58 COCCOPHYCEiE. 
 
 Bac, and possessing a diameter of aboTjt 1-170", already contains a 
 certain number of enlarged gonidia, destined in due time to become its 
 own progeny. Not only so, but long before its discharge, and while yet 
 it exists as a daughter-cell within tie protecting cavity of the parent 
 generation, these selected gonidia are already visible as spols larger and 
 darker than their fellows. (Plato 22, Fig. 1.) 
 
 " The history of these selected gonidia, as it may be traced in a 
 daughter-sphere recently cast forth to seek its fortunes in the world of 
 waters around it, is as follows : — The enlarged gonidium is at first a flat, 
 thin circular disc, appressed to the internal surface of the sphere, and 
 being surrounded by eight of the ordinary zoospores, is derived from 
 the coalescence of the two central ones out of a group of ten. (Plate 
 23, Figs. 1, la.) Shortly, this disc assumes a more distinctly oval form, 
 with a slight constriction across its lesser diameter, in which stage it 
 often much resembles a young Cosmarium. (Plate 23, Figs. 2, 2a.) It 
 is soon seen to be clearly subdivided into four, and its thickness having 
 grown pari passu with its superficies, the group now protrudes into the 
 internal cavity of the parent-plant. (Plate 23, Figs. 3, 3a.) Repeated 
 subdivision now goes on rapidly (Plate 23, Figs. 4, 4a), till the whole 
 body assumes a sphserical form, a distinct cell wall being at the same 
 time formed, which is revealed by careful illumination, and still more 
 clearly by the use of reagents, as a hyaline sphere concentric to and of 
 larger diameter than the green one within it, so that there appears to be 
 a clear space or ring between the two when seen in section. (Plate 22, 
 Fig, 5, 5a.) Finally, the young Yolvox consists of a vast number of 
 deep green granules closely packed together, and by mutual pressure 
 driven to assume a more or less distinctly hexagonal form, and corres- 
 ponding in number to the gonidia which are to stud its surface when its 
 growth is completed. Shortly hereafter, the whole organism continuing 
 to increase in size, clear spaces appear between the gonidia, showing 
 that the enlargement of the cell wall and its interspaces is outstripping 
 that of the gonidia^ which are now approaching maturity. The inter- 
 lacing connecting threads are developed simultaneously. (Plate 22, Fig. 
 lo.) During the whole process the centre of the young Volvox spheres 
 continually recedes from the periphery of the parent, so that when the 
 group of young ones has attained the full development of which it is 
 capable in this stage they are often pretty clpsely packed in the internal 
 space, and sometimes even slightly deformed by mutnal pressure, each 
 by this time closely- resembling the parent in miniature, and already 
 containing enlarged gonidia of the third generation. (Plate 22, Fig. 1 .) 
 By this time the clear space originally visible between the gonidia and 
 the cell wall has been obliterated, and the cilia may be seen protruding 
 through the latter. Some writers state that the daughter-cells rotate 
 at this period within the parent cavity. I have frequently seen them 
 oscillate so far in one direction and then back to their original position, 
 but have never observed a true rotatory motion. Finally, the young 
 Volvoces are liberated by the rupture of the parent sac, at a special 
 point, clearly marlied out for this purpose in its structure. I have not 
 met with any observations on this point, but have fully convinced 
 myself that it may always be predicted at what point this rupture will 
 be effected. 
 
 " The combined action of the pairs of cilia in which the gonidia 
 terminate is the actuating power whence proceed both the rotatory and 
 the progressive movement of Volvox, and these are both in a definite 
 direction. If an imaginary axis be drawn through the sphere, the pro- 
 gressive motion being, bo to speak, from the north to the south pole of 
 that axis, the rotatory motion is usually from west to eost, though not 
 always, being occasionally reversed for a few seconds ; but for the 
 
VOLVOCINBiB. 59 
 
 greater part of the time it is regularly in the direction indicated, and 
 the point of rupture of the sphere will be at its north pole, 
 
 " It ia difficult to determine precisely how this rapture is accomplished, 
 but I believe it to be by a special contraction of the walls of the parent, 
 or of the invisible primordial utricle, not by the outward pressure of 
 the daughter spheres, this force being evidently inadequate to produce 
 the result where their number is small, whatever it may be when it 
 reaches its maximum. 
 
 " Shortly before the emission of the young the cell commonly assumes a 
 slightly pyriform shape, and then slowly opens at its apex, but the aperture 
 is of less diameter than that of the young Volvoces, and as each of these 
 passes oat, the month of the bag is visibly stretched, and resumes its 
 original size after each daughter sphere has escaped, so that it evidently 
 possesses considerable elasticity, a property also made manifest by the 
 fact that the normal form of Volvox may be considerably flattened by 
 the pressure of a glass cover, and yet resume both its sphserical form and 
 its motion when this pressure is removed. 
 
 " Moreover, the daughter sphere passes out without rotating, and from 
 ■whatever cause it derives its impulse, this often suffices to drive the 
 young Volvox clear of the mouth of the sao to a distance eqaal to 
 several times its own diameter, in which position it pauses motionless 
 for some seconds, and then, commencing to rotate gently, sails away, at 
 first slowly, then more and more rapidly, to enjoy its independent 
 existence. 
 
 "After the rnptnre of the sac, the gonidia near the edges of the 
 opening are seen to quiver, from the action of the cilia, where they are 
 partially freed from the support of the surrounding envelope, and the 
 same thing occurs when they are forcibly torn from their attachment, 
 in which case they may even move for awhile freely through the 
 ■water. 
 
 "The general action of the cilia continues for some time, and the 
 empty sphere rotates as before, its general direction being still from 
 north to south, with the open end to the rear. After a time, which I 
 cannot specify, the cilia cease to play, and the organism decays, having 
 fulfilled its destiny in life. 
 
 " The birth of the young Volvoces is affected by various circumstances. 
 Doubtless the process is, under natural conditions, most active in the 
 early hours about dawn, when the analogous functions of similar 
 organisms are well known to be most energetic, but in order to see the 
 phenomenon in full vigour it is only necessary to place a number of 
 mature parent- spheres, such as are found in every colony, in a shallow 
 live-trough, and to bring them into a warm room. In an hoar's time 
 almost all the young plants will have been liberated. Light and heat 
 stimulate the action, while cold and darkness retard it. The ciliary 
 action is affected in a remarkable degree by altered external conditions . 
 If a drop of water considerably colder than that in which the Volvoces 
 are floating be allowed to flow in under the cover.glass, the whole are 
 paralysed for some seconds, after which they slowly resume their motion, 
 A sudden mechanical shook produces a similar effect. A sufficient 
 degree of heat to make the water distinctly tepid to the feel causes 
 instant and simaltaueous death of the whole colony. 
 
 *' Daring the day the majority of the Volvoces contained in a shallow 
 vessel rise to the surface, although they avoid strong direct sunshine, 
 ■while at night they retire in a cloud to the bottom. 
 
 " The astonishing number in ■which the spheres at times appear in 
 some pool, and their equally sudden disappearance, have been frequently 
 remarked. Doubtless a very slight change in external conditions suffices 
 on the one hand to favour the development of countless thousands of 
 
60 COCCOPHYCEiE. 
 
 yonng plants, and on the other, either to destroy the vitality of the 
 whole colony or to drive it to seek ref age in deeper water. 
 
 " A carious instance of this sensitiveness to varying conditions of light 
 and heat occnrred to myself, I had two shallow vessels in a north 
 window, each containing a goodly snpply of Volvox. Cold and inclement 
 weather, which prevailed for weeks together, seemed to check their 
 increase, for I fonnd but few young spheres from day to day among the 
 older ones. Thinking that a moderate degree of warmth would tend 
 to increase my colony, I transferred one vessel, fortunately not both, to 
 the floor of a warm greenhouse. In forty-eight hours all were dead, and 
 in a few days scarcely a vestige remained of the countless corpses which 
 had copiously strewed the bottom of the glass. 
 
 " We must now revert to the minute structure of the mature parent- 
 sphere, which has been exhaustively studied by Cohn, Busk, and 
 Williamson. 
 
 " In the outset it should be stated that the last-named observer 
 believes that there are two distinct forms of Yolvox, in one of which 
 the peculiar structure which I am about to describe exists, while it ia 
 absent from the other. Busk disputed the accuracy of Williamson's 
 observations on this point, but in an appendix published subsequent to 
 the body of his essay he states that he has detected this same structure 
 in specimens from Manchester, but not in his own. 
 
 " I have failed to develop it by the means recommended by William- 
 son, but have succeeded in making it evident enough in a great number 
 of specimens from Sutton, by the use of these reagents, and especially 
 by the application of aniline purple, an invaluable auxiliary in the 
 examination of minute vegetable cell-structures. 
 
 " This substance stains the protoplasmic elements of such structures 
 to a colour which appears deep purple by direct light and crimson by 
 dark background illumination, and reveals details which are wholly 
 invisible without its use. 
 
 " The colour is, however, greedily absorbed by some of the materials 
 used by the microscopist, so that a jidicious choice of these is necessary 
 to ensure success. Objects stained iu this manner are, .for instance, 
 rapidly bleached if mounted in gold-size cells, and I have for the present 
 adopted zinc- white in its place. Among other reagents which I have 
 used are eosin, iodine, iodised glycerine, carmine solution, potassium 
 permanganate, nitrate of silver, and other salts, some of which bring 
 into view various parts of the minnte structure of plants ; but aniline 
 colours, applied with due precautions, produce the most rapid and 
 striking effect. 
 
 " Professor Williamson describes the structure in question as a net- 
 work of lines dividing the whole surface into hexagons, in the centre of 
 each if which is seated one of the gonidia. 
 
 " The delicate ' protoplasm-threads ' proceeding from each of these 
 to its six sniTounding neighbours never pass - through the angles of the 
 hexagons, but always through the side of each hexagon to the next 
 gonidinm. { Plate 2JS, Fig. 3.) Hence it appears that ' the points of 
 adhesion are chosen prior to the development of the outer cell 
 membrane,' in which light Williamson regards the hexagonal division. 
 In his specimens this structure was developed by immersion in glycerine 
 for some time. I have failed to obtain more than the faintest sugges- 
 tion of it by these means, but it is often brought out by the application 
 of aniline purple, as is also an important detail shown in drawings 
 made from his preparations, viz., that at the angles of the contiguous 
 hexagons there is sometimes a distinct doubling or separation of the 
 lines, whence he concludes that each side of the figure is really formed 
 by two delicate cell-walls in close juxtaposition, the duality of which is 
 
VOLVOCINEiE. 61 
 
 only made evident by the action of reagents. (Plate 22, Fig. 2.) He 
 regards the globe of Volvox as a ' hollow vesicle, the walls of which 
 consist of numerous angular cells filled with green endoohrome, &o., the 
 interoellnlar spaces being more or less transparent,' and the ciliated 
 zoospore as representing the endochrome of a cell having two walls, the 
 internal one being separated from the outer cell-wall, except at a few 
 points where it is retained in contact by the connecting filaments, and 
 the external one forming the hexagonal divisions on the surface. He 
 further holds that the periphery of the sphere, when seen in section, 
 has an appreciable thickness, its inner margin being definite and parallel 
 to the outer one ; and that the sides of the hexagons being continued 
 downwards through the thickness of the outer membrane, the appear- 
 ance of all these structures, if they could be seen simultaneously, would 
 be that shown in Plate 23, Fig. 6. 
 
 "Even in deeply stained specimens I have never been able to detect 
 the existence of these hexagons as other than an entirely superficial 
 structure, and at present my impression is that the hexagonal structure 
 has a different significance. 
 
 " In the very early stage of Volvox-Iife the embryo gonidia are 
 encased in a distinct transparent outer-sphere. (Plate 23, Fig. 5, 5a.) At 
 a later period, owing to the more rapid growth of the gonidia than of 
 the case, the latter closely invests the former, which are, in fact, 
 embedded in it. In the next stage, if not in the earlier condition, by 
 the continued growth of the gonidia at a greater rate than that of the 
 containing sphere, they are so closely appressed as to assume the hex. 
 agonal form, and the interstices must of necessity consist of a thin film 
 of the substance of the containing sphssrical envelope, moulded, so to 
 speak, into corresponding forms. But now the diameter of the young 
 Volvox, which is by this time sent forth on its independent career, 
 rapidly increases, the gonidia assuming their sphssrical or pyriform 
 shape as their mutual pressure diminishes, and being hourly separated 
 by greater intervals. If, now, the actual formative matter of the sphere 
 receives no further or only a disproportionate increment, but is 
 gradually attenuated by continued expansion, as a soap bubble is dis- 
 tended by blowing into it, the hexagonal lines into which it has been 
 moulded by the previous mutual pressure of the embryo gonidia will be 
 gradually stretched in all directions into finer proportions ; and just as 
 this figure is that which is necessa/rily assumed by a number of sphserical 
 bodies under mutual pressure, so the most economical disposition of this 
 particular part of the Volvox-structure will necessitate its constant 
 attenuation into hexagons of ever-increasing delicacy. (Plate 22, Figs. 
 1, 8 ; Plate 23, Fig. 7.) If the process be continued long enough, it 
 may finally result in the structure becoming too filmy to be detected by 
 any microscopical observation j and it is worth noticing that it is 
 usually in spheres of small or medium diameter that the hexagonal 
 divisions can be developed, and not in those of the largest size. Such 
 appears to me at present to be the rationale of the formation of this 
 structure. 
 
 " The internal cavity of the sphere is said to be filled with a ' muci- 
 laginous fluid.' (If a Volvox be ruptured under a cover-glass, and aniline 
 purple introduced by capillary attraction, the colour seems to be for a 
 while repelled at that part which is in front of the rnpture, and to flow 
 round it on either side. It is only after a considerable time that it 
 gradually penetrates this space, and brings out, by staining it of a deep 
 purple tint, a mass of hazy matter, from which proceed streaks or 
 lines radiating more or less regularly from its south pole. This structure, 
 to which I do not think attention has been hitherto called, is also some- 
 times developed in deeply stained specimens within the slightly 
 
 K 
 
62 
 
 C0CC0PHYCBJ3. 
 
 mptnred sphere, and seems to show that there is a denser layer of 
 thick matter, whatever its natnre may be, disposed in a somewhat 
 regular manner, being concentrated near the south pole of the axis of 
 rotation, whence it spreads over the inner surface in streaks resembling 
 the lines of longitude on a terrestrial globe. 
 
 " Both from its position and from the rapidity with which it is stained 
 by aniline purple, without which its existence is apparently absolutely 
 undemonstrable — (in which respect it is in marked contrast to the outer 
 cell-wall, which latter is only faintly tinted by somewhat prolonged 
 application of the reagent, and then only where the hexagonal structure 
 exists) — I have no doubt that this inner layer is the true ' primordia 
 utricle * of the cell, and possesses that character of vital and formative 
 matter which distinguishes this element of cell-structure from the outer 
 wall, which, on the other hand, probably consists of cellulose or some 
 similar compound. Probably the an-angement of this inner layer, in 
 radiating lines or ribs, contributes to the elasticity of the fabric, whereby 
 it is enabled to open at a given point for the escape of the young, and 
 to contract again after their emission. 
 
 " The increase of individuals by the means already described is 
 strictly an instance of subdivision. 
 
 " But Volvox gloiator also affords an instance of in^ne alternation of 
 generations. As may probably be aflSrmed of all living organisms, its 
 life-history would be incomplete without a process of sexual reproduc- 
 tion, and accordingly, after a long sequence of asexual generations, a, 
 strictly sexual process intervenes, from which result certain spores 
 destined to lie dormant for u. while, and, like the zygospores of the 
 Conjugate Algae, to resist vicissitudes of condition and climate 
 through the rigours of winter, and then to produce the parent form in 
 the succeeding year, when external conditions again favour its develop- 
 ment. 
 
 " Cohn fully traced the various stages of this process, and described 
 them in the ' Beitrage znr Biologie der P&auzen ' (1876, Vol. I., Heft. 3), 
 and in the 'Anualesdes Sciences Naturelles ' (4 i^me Ser. Bot., Tom. 
 v., 323) ; and his observations have been more or less confirmed by 
 other investigators, especially by Carter (Ann. Nat. Hist., 3rd Ser., Vol. 
 III., 1859, p. 1), and more recently, in 1877, by a French botanist, M. 
 F. Henneguay. 
 
 " Cohn and Carter both hold that there are two varieties of Volvox,* 
 one monoecious, the other dioecious, and the latter maintains that 
 SplUBrosira Vol/vox is the male form of the dioecious sub-species. Be 
 that as it may, the reproductive process in the monoecious form is as 
 follows : — The sexual reproductive cells, male and female, occur in 
 spheres of unusual size in the autumn, and are few in proportion to the 
 number of sterile cells, and the reproductive process does not occur 
 simultaneously with, but as a climax to a long series of asexual genera^ 
 tions. On their first appearance the gynogonidia or female cells are 
 about three times the size of the sterile ones, of a. deep green colour, 
 and of a frothy consistency from abundance of vacuoles. They are 
 easily distinguished from the parthenogonidia by their never sub- 
 dividing. (Plate 22, Pig. 5d.) They next become flask-shaped, their 
 narrow end touching the periphery of the sphere, and the broader end 
 hanging free in the internal cavity. (Plate 22, Fig. bb^.) Finally, they 
 assume a sphserical form, and become oospheres, each enveloped in a 
 gelatinous membrane. (Plate 22, Fig. 54', J*.) 
 
 "The androgonidia, or male cells, at first closely resemble the par- 
 thenogonidia, but undergoing division in two instead of three directions, 
 
 * The two forms are here accepted, after Stein, as Volvox globator and Volvos 
 minor. 
 
VOLVOOINEJS. 63 
 
 deyelop into plates or discs of cells, not into spheres, and ultimately 
 resolve themselves into bundles of naked elongated cells, in which the 
 chlorophyll is transformed into a, reddish pigment, each with a long 
 colourless beak, with a red ' eye-spot ' and two cilia. (Plate 22, Fig. 
 5a, a^.) About the same time that the oosphere is mature these 
 antheridia begin to move from the combined action of their cilia (Plate 
 23, Fig. 10), and then break up into separate antherozoids, which finally 
 become free, and move rapidly within the cavity of the sphere. (Plate 
 23, Fig. Sa-*.) Assembling round the oospheres, they penetrate the 
 envelopes of the latter (Plate 22, Fig. 4), coalesce with their contents, 
 and the oosphere, thus fertilised, becomes an oospore, which soon develops 
 a cell-wall covered with conical stellate projections, and a second smooth 
 internal membrane. (Plate 23, Fig. 11.) The chlorophyll now gradually 
 disappears, and is replaced by an orange red pigment. In this condition 
 the oospore constitutes the Yolvox stellatus of Ehrenberg. It is liberated 
 by the decay of the parent-cell, and sinks to the bottom of the water 
 to hibernate. The subsequent history of these bodies has been traced 
 by Cienkowski, and more recently by Henneguay (" Jonrnal de 
 Micrographie," Vol. II., p. 485, Bull. Soo. Philomath, Paris, July, 1878). 
 
 "Cohn believed that they must be dried up before germination was 
 possible. Henneguay has now observed that this is not so. In spring 
 the outer case of the spore (exospore) is ruptured, and the swollen con- 
 tents (endospore) project through the opening. The contents then 
 divide gradually into two, four, eight, sixteen, or more small cells, which 
 become bright green, each meanwhile acquiring two vibratile cilia while 
 still contained within the inner membrane of the spore. The cells, at 
 first in close apposition, separate further from one another by interposi- 
 tion of gelatinous hyaline matter, the outer membrane disappears, the 
 cilia become active, and the young Volvox, already containing some 
 elements larger than the others, and destined, in due course, to produce 
 daughter-spheres, moves freely through the water. ' The spores of 
 Volvox, therefore, germinate in water, and each of them produces a 
 single colony by a process of segmentation identical with that which 
 gives rise to a daaghter-oolony at the expense of a cell of the mother- 
 colony.' 
 
 "The sequence of asexual generations is repeated for many months, 
 and in the following autumn the alternation of generations is again 
 completed by the intervention of the processes just described." 
 
 Volvox globatoz. Linn. Syst. Ed. x. 
 
 Larger coenobia, with very numerous cells (12,000), always 
 with daughter-ccenobia enclosed within the mother, evolved 
 without sexuality ; fructiiication diojciou^^ the male coenobia 
 nourishing numerous red fascicles of sperfcatozoa ; the female 
 coenobia originating 20-40 sexual ceMs, which after fecundation 
 are resolved into as many red globose oospores, surrounded by a 
 hyaline stellate epispore (=Volvox stellatus, Ehr.). 
 
 Size. Coenobium as much as 1 mm. diam. 
 
 Ehrb. Infus. 68, t. 4.- Dujardin Zoophy. 312, iii. f. 25. Stein 
 Infus. p. 46. Eabh. Alg. Eur. iii. 97. Pritchard Infus. 526, 
 t. 20, f. 32-47. Busk. Trans. Micr. Soc. 1853, p. 31. Wil- 
 liamson Trans. Micr. Soc. 1853, p. 45. Currey Ann. Nat. Hist. 
 1859, p. 5. Dr. J. B. Hicks in Micro. Journ. 1861, p. 281 ; in 
 
64 COCCOPHYCE^. 
 
 Popular Science Review, vol. v. p. 137. A. W. Wills in 
 Midland Naturalist, Sept.-Oct., 1880. A. Bennett in Popular 
 Sci. Rev. 1878, p. 225. 
 
 Sphcurosira volvox, Ehr. Infus. (roale).- Pritch. Infus. p. 
 526. Williamson in Popular Sci. Review, vol. ix. p. 225. 
 
 Volvox stellatus, Ehr. Infus. (oospore). 
 
 In clear pools, ponds, &c. 
 
 The relationship of Sphcerosira volvox to Volrox globator has not been 
 satisfactorily determined (see Williamson), although there remains no 
 doubt of the existence of relationship. Some regard it as the male 
 form, but Professor Williamson considers it a> peculiar condition of 
 Volvox. 
 
 For details of a Bnccessfnl experiment in keeping Volvom during the 
 winter see N. E. Brown in Gardener's Chronicle (1879 p. 599) and 
 " Ponds and Ditches," by M. C. Cooke, p. 63. 
 
 Plate XXII. figs. 1-3. Volvox glolator, after A. W. Wills; 4-5, after 
 Cohn. Explanation given above. 
 
 Plate XXIII. figs. 1-5. After A. W. Wills ; 6, ideal section after 
 Williamson ; 7, after Wills — also fully described above ; 8-9, X 300 
 after Stein ; 10, complete antheridium ; 11, stellate resting spore or 
 oosphere X 400 ( Volvox stellatus) ; 12, spermatozoids X 600. 
 
 Plate XXIV. Male plants of Volvox, known as SpJicerosira volvox, 
 after Williamson, Fig. 1 , coanobiam ; 2, protoplasmic mass from the 
 coenobinm, containing granules ; 3, mass divided in two ; 4, the same 
 divided into four ; 5, the same divided into sixteen ; 6, further division 
 into thirty-two, provided with movable cilia ; 7, discoid family revolving 
 within its mother-cell. 
 
 Volvox minor. Steiyi Infus. j). 47. 
 
 Coenobia and the number of cells smaller ; the number of 
 daughter-coenobia evolved without sexuality within the mother, 
 1-9 ; fructification sexual, monoecious ; many male cells 
 changing into bundles of spermatozoa; 5-10 faflttt cells in 
 the same ccenobium, after fecundation, evolved ^to^^many 
 oospores, surrounded by a smooth epispore (==Volvox 
 Ehr.). 
 
 Size. Variable, but smaller than the preceding. ^ 
 
 Rabh. Alg. Eur. iii. 98. Stein Infus. t. 
 
 Volvox globator, of authors, in part. 
 
 Volvox aureus, Ehrb. Inf. 71, t. 4, f. 2 (oospore). 
 
 In similar places to the preceding. 
 
 Plate XKV. Volvox minor X 400 after Stein. Fig. 1, portion of 
 ccenobium with two young daughter families ; 2, ccenobium with two 
 young daughter families enclosed in mother-cell ; 3, coenobinm with five 
 young fertile cells ; 4, coenobinm with six young fertile cells j 5, a fer- 
 tile cell enclosing numerous vacuoles indicating the commencement of 
 subdivision ; 6, isolated daughter-family still enclosed in the mother- 
 cell ; 7, encysted cell — the Volvox aureus of Bhrenberg ; 8, isolated 
 ordinary individual enclosed in a Sask-shaped cell. 
 
VOLVOCINEiE. 65 
 
 Genus 40. EUDO&IMA. Ehri. (1831.> 
 Coenobium oval, involved in a common tegument ; cells green, 
 globose (16-32), enclosed witbin a single membrane, bearing 
 vibratile cilia, often witb a red spot (eye-spot), distributed 
 around the hyaline sphere at equal distances apart. Asexual 
 propagation in all the coenobia, the cells of which are divided 
 into 16-32 parts, and soon evolved into new coenobia. Sexual 
 propagation in all the ccenobia, the cells being converted into 
 motionless oospores enclosed in a narrow cpispore, afterwards 
 becoming red. 
 
 The most complete account we possess of the life-history of Eiidorina 
 is that hy H. J. Carter (^Ann. Nat. Hist., Oct., 1858), of which the follow- 
 ing is a summary: — Unable to recognise this organism in its simplest 
 form as a solitary cell, nor any stage of segmentation prior to the third 
 degree of duplicative subdivision into 16 cells, he commences from this 
 period. 
 
 At this time, which we call the first stage, the Eudorina consists of an 
 ovoid green body, partial]}' divided into the number of cells just men- 
 tioned, each of which is provided with a pair of cilia, which project 
 through a thin gelatinous envelope that surrounds the whole mass. It 
 is now about 1-llOOths of an inch long, i.e., not move than the diameter 
 of the Ohlamydococcus cell, and swims by means of its cilia, with the 
 small end foremost, and with a rotatory motion on its longitudinal axis, 
 as often from right to left as from left to right. An eye-spot is also 
 present in each of the four anterior cells, but seldom visible in the rest 
 at this period. 
 
 As development progresses each cell is provided with a spha3rioal, 
 translucent utricle, an eye-spot midway between the cilia and the oppo- 
 site end of the cell, a contractile vesicle at the base of the cilia, and the 
 pair of cilia themselves. 
 
 During the second stage each of the cells again undergoes duplicative 
 division, and the whole organism becoming larger, they are separated 
 from each other, and being no longer subject to compression, become 
 sphserioal and enclosed respfeotively within distinct transparent capsules. 
 The Eudorina is now six times as long as in the first stage, and contains 
 32 green cells, which are evidently situated between two large ovoid, 
 colourless, transparent cells, one of which bounds a similarly shaped 
 cavity in the centre of the Eudorina, and the other is the original cell 
 wall, round which again is the newly secreted envelope. Thus we see 
 that the Budorina is derived from a simple (daughter) cell, and that its 
 green cells have resulted from a duplicative subdivision of the green 
 matter which lined the cavity of this cell. Arrived at this state, which 
 we shall see is that of maturity, we also observe that the posterior part 
 of the envelope becomes crenulated, apparently from flaccidity. 
 
 After this, however, it again presents another phase, which may be 
 called the third, or last, stage of development. Here each cell again 
 undergoes a rapid duplicative subdivision into 16 or 32 cells, which, in 
 the group, assume a more or less oblong figuie respectively, and thus the 
 Eitdorina's length is increased to 10 times that of its first stage. The in- 
 ternal structure now gradually breaks down before the external envelope, 
 when for a short time the groups may be seen swimming about the cavity 
 thus formed, till at last the envelope bursts and they become liberated. 
 What becomes of them afterwards he could not state from observation, 
 but the green cells having been greatly reduced in size by the latter sub- 
 
66 coccophycbjE. 
 
 divisions it is probable that many of the groups, if they do not form new 
 individuals, sooner or later become disintegrated, and the Mudorina thus 
 eventually perishes. 
 
 When, however, the process of impregnation takes place, the division 
 stops at the second stage, that is when the Mudorina consists of 32 cells 
 of the largest kind, each of which is about l-1866th of an inch in dia- 
 meter within its capsule, which is therefore a little larger. The process 
 is as follows : — 
 
 At a certain period after the second stage has become fully developed 
 the contents of the four anterior cells respectively present lines of dupli- 
 cative subdivision, wliich radiate from a point in the posterior part of the 
 cell (in the subdivision of other cells the lines of iissiparation tend 
 towards the centre of the cell). These lines, which ultimately divide 
 the green contents of the cell into 64 portions, where the division stops, 
 entail a pyriform shape on the segments, from whose extremities a mass 
 of cilia may be observed waving in the anterior part of the cell of the 
 parent, while yet her own pair of cilia are in active motion, and her eye- 
 spot still exists in situ on one side of her progeny, thus showing that the 
 latter may be almost fully formed before the parent perishes. At length, 
 however, this takes place, and the progeny (Spermatozoids) separate from 
 each other, and iinding an exit, probably by rupture, through the effete 
 parent cell and her capsule, soon become dispersed throughont the space 
 between the two large ovoid cells mentioned, where they thus freely come 
 into contact with the capsules of the twenty-eight remaining, or female 
 cells. 
 
 The form of the spermatozoid now varies at every instant from the 
 activity of its movements, and the almost semifluid state of its plasma. 
 Its changes, however, are couilned to elongation and contraction ; hence 
 it is sometimes Unear-fusiform, or lunular, at others pyriform, short, or 
 elongate. The centre of the body is tinged green by the presence of a, 
 little chlorophyll, while the extremities are colourless, the anterior one 
 bears a pair of cilia, and there is an eye-spot a little in front of the middle 
 of the body, also probably a nucleus. It is about l-2700th of an inch 
 long and about one-fifth as broad. 
 
 Once in the space mentioned, the spermatozoids soon find their way 
 among the female cells to the capsules, of which they apply themselves 
 most vigorously and pertinaciously, flattening, elongating, and changing 
 themselves into various forms as they glide over their surfaces, until they 
 find a point of ingress, when they appear to slip in, and, coming in con- 
 tact with the female cell, to sink into her substance as by amalgamation. 
 This author explains that there was some difficulty in seeing the act of 
 union, but of the act itself he entertained no doubts. Eudorina in this 
 stage also may frequently be seen with all the four anterior cells absent, 
 and only a few spermatozoids left, most of which are motionless and 
 adherent to the capsules, indicating that the rest have disappeared in the 
 way mentioned. Lastly, many Hudmince in this stage may be observed 
 with not only the four anterior cells absent, but with hardly a spermato- 
 zoid left, indicating that the whole had passed into the female cells or 
 had become expended in the process of impregnation. 
 
 What changes take place in the Eudorina after this he had not been 
 able to discover. At the time the female cells appear to become more 
 opaque by the incorporation of the spermatozoids, and the orenulated 
 state of the posterior part of the envelope in this stage seems also to in- 
 dicate an approach to disintegration. 
 
 While undergoing impregnation the female cells always contain from 
 2 to 4 nuclei, as if preparatory to the third stage of development into 
 which they are sometimes actually seen passing, with the spermatozoids 
 present and scattered among them ; but the effect of impregnation 
 generally seems to arrest this stage, and thus save the species from 
 that minute division which leads to destruction. 
 
VOLVOCINB^. 67 
 
 The author cited then goes on to explain how he conceives the other 
 stages of the Eiidorina are passed, which he had not the opportunity 
 of observing. The whole memoir is one of great interest, and will 
 well repay perusal by those who are investigating this subject. 
 
 Eudorina elegams. Ehrh. Monats. Berl., 1831, j). 78. 
 
 Coenobia oval, cells usually 32, globose, either scattered or 
 quaternate, eight at each pole, distributed in three parallel 
 circles, at equal distances from each other, around the periphery 
 of the coenobium. 
 
 Size. Coenobium •04--15 mm. long. Cells •018-'022 mra. 
 diam. 
 
 Eabh. Alg. Eur. iii. 99. Ehrb. Infus. 63, t. iii. Pritchard 
 Infus. p. 520. Carter, in Ann. Nat. Hist., Oct., 1858. 
 
 Pandorina elegans, Dnjard. Zoophy., p. 317. 
 
 In standing water. 
 
 Formerly found at Hackney and Hampstead, most abundant in the 
 ppring of the year, but doubtless quite extinct at both places. " Clusters 
 are often seen," says Pritchard, "in such amazing numbers along with 
 Tolvox and Chlainydomonas pulvisculus as to render the water of a 
 decided green colour, especially towards the edges." 
 
 Plate XXVI. fig. 1. a, 16-oelled family ; 2, sixteen-celled family 
 dividing into a 32-celled family ; 3, part of a family, showing division in 
 pairs; 4, 32-celled family divided into daughter-families; 5, one-celled 
 daughter-family. All after Stein. 6, colony with three spermatic 
 cells, having burst; 7, spermatic cells X 400 ; 8, spermatic cell X 800 ; 
 9, spermatozoids X 800. After Carter. 
 
 GSNUS41. PANDORINA. Ehrh. (1830.) 
 
 Coenobium globose or subglobose, invested by a broad colour- 
 less hyaline tegument ; cells green, granulose, globose (16, 32, 
 or 64), included within a single rather thick membrane, bearing 
 two vibrating cilia, with or without a red spot, aggregated in a 
 botryoid manner. 
 
 Propagation the same as in Eudorina. 
 
 Henfrey's emended character of this genus was in the following 
 terms :■ — " Frond a microscopic, ellipsoidal, gelatinous mass, containing, 
 embedded near the periphery, sixteen or more biciliated, permanently 
 active gonidia, arranged in several circles perpendicular to the long axis 
 of the frond. The gonidia almost globose, with a short beak-like 
 process, a red spot, and a pair of cilia which project through the 
 substance of the frond to form locomotive organs upon its surface. 
 Reproduction — I., by the conversion of each gonidium into a new frond 
 within the parent mass ; II., by the conversion of the gonidia into 
 encysted resting spores, which are set free and (P) subsequently ger. 
 minate to produce new fronds." — Quart. Micro. Journ, (1856), p. 49. 
 
68 COCCOPHTCE^. 
 
 Pandorina moram. Ekr. Inf. p. 53, t. ii. /. 33. 
 
 Coenobium globose. Cells green, 16-32, arranged about the 
 periphery. In the forms which produce the resting spores, the 
 cells are crowded together in the centre. Resting spores after 
 becoming encysted bright red. 
 
 Size. Coenobium -2 mm. Cells ■01--015 mm. diam. 
 
 Rabh. Alg. Eur. iii. 99. Henfrey Micr. Trans. (1856) p. 
 49, t. 4. Pringsheim Monatsb. Berlin, Oct., 1869. Ann. 
 Nat. Hist. V. (1870) p. 272. Pritchard Infus.pp. 157 and 517, 
 t. xix. fig. 59-69. Braun Rejuv. pp. 169-209. 
 
 In standing water. 
 
 " Fronds hyaline from about 1-80" downwards. Gonidia either 16, 
 and then arranged in fonr circles of 4, or 32 and then in fire circles, two 
 at the poles of 4, and the intermediate three of 8 gonidia, which in the 
 perfect form stand near the periphery, and wide apart. In the forma 
 which produce the resting spores the gonidia are crowded together in 
 the centre. The gonidia are green, but the contents of the resting 
 spores, after they have become encysted, are couTerted into oily and 
 granular matter of a bright red colour." — Renfrey. 
 
 Pringsheim, in his memoir "on the pairing of Zoospores,*'* makes 
 special reference to this species. He says that asexual reproduction 
 takes place in Pandorina, as in other multicellular Volvocineae, by the 
 formation of a perfect young plant in each cell of the mother plant. By 
 the gradual dissolution of the general envelope and of the special mem- 
 brane of the mother-cells, the young plants become free, and escape. In 
 sexual reproduction, as in the asexual, the membrane of the old plant 
 swells, and sixteen yonng plants are formed. The young plants, how- 
 ever, are (at least in part) not nenter, but sexual, and either male or 
 female. Whether the mother plant is monoecious or dioecious is difficult to 
 determine, because the male and female plants are externally alike, and 
 can hardly be distinguished with certainly during copulation. There is 
 no striking difEerence in structure between the sexual and asexual 
 plants, although, amongst the former, plants with less than sixteen cells, 
 especially with eight cells, are oftener produced. Moreover, the dissolu- 
 tion of the membrane of the mother-cell proceeds more slowly than in 
 the case of neuter plants, one result of which is that the young asexual 
 plants vary much in the extent of their growth, and continue united in 
 groups of different sizes for a long time after their formation, according 
 as a greater or less number of them have happened to become free from 
 the gelatinous mass in which they were embedded. 
 
 As the individual groups are at first motionless, and the mother plant 
 loses its cilia during the formation of the young ones, the entire group 
 is at first entirely quiescent. But afterwards the young sexual plants, 
 like the neuter ones, produce upon each of their cells two cilia, which 
 conunence their motion as soon as the enveloping mucus admits of it, 
 and thus ultimately the entire group assumes a state of active rota- 
 tion. During the rot-ation of the groups the same process of expan- 
 sion and dissolution takes place in the membrane of the sexual plants 
 as occurred in the mother plant j but the contents of the cells of the 
 sexual plants do not undergo division, but combine to form a single 
 zoospore, which becomes free by the rapid dissolution of the mem- 
 branes. In their general structure these zoospores differ in no way 
 
 * Monatsbericht, Hoy. Acad. Sciences, Berlin, Oct.. 1869. Translated 
 in " Annals of Natural History," Vol. V. (1870), p. 272. 
 
VOLVOCINEiB. 69 
 
 from other zoospores. At their colourless apex they exhibit, like 
 other zoospores, a red body placed on one side of the apex, and two 
 long vibrating cilia, by which they move in the manner common to 
 zoospores. The individual zoospores exhibit no marked difEerences, 
 except that they vary in size within tolerably wide limits, but not in a 
 manner to indicate the existence of two different sorts. 
 
 Amongst the groups of isolated zoospores of different sizes some are 
 at last seen to approach one another in pairs. They come into 
 contact at their anterior hyaline apex, coalesce with one another, and 
 assume a shape resembling a, figure of 8. The constriction which 
 marks their original separation disappears by degrees j and the paired 
 zoospores form at last a single large green globe, showing at the cir- 
 cumference no trace of their original separation. It may be seen, 
 however, that the globe is larger than the individual neighbouring zoo- 
 spores, that it has a strikingly enlarged colourless mouth spot, with 
 two red bodies on the right and left, and that it is furnished with four 
 vibrating cilia originating in pairs near the two red spots. The four 
 cilia, however, soon become motionless, and together with the red spots 
 disappear. 
 
 This act of conjugation occupies some minutes from the first contact 
 of the zoospores to the formation of the green globe. The latter 
 becomes the oospore, which, after growing slightly larger, and assuming 
 a red colour, germinates after a long period of rest, and brings forth a 
 new Pandorina. There is hardly any appreciable difference, except in 
 size, between the male and female zoospores. Most frequently a small 
 zoospore pairs with a larger one ; but two of equal size often unite. 
 Probably both the females and the males vary much in size, the former 
 more so than the latter. 
 
 With regard to the entire plants from which the zoospores are pro- 
 duced, there is little doubt that those of the largest size are females j 
 but the sex of the smaller and middle-sized ones cannot be determined 
 with any certainty. The germination of the oospore is like that of other 
 Yolvocmete, especially resembling in its early stage the germination of 
 the resting spores produced by the miorogonidia of Hydrodictyon utri- 
 culatum. The oospore bursts, and produces a single large zoospore (in 
 rare cases two or even three), which divides into sixteen cells, and 
 becomes a young Pandorina. 
 
 Plate XXVII. fig. 2. Pandorina morv/m — a, a very small family ; J, 
 c, sixteen -celled families ; d, eight-celled family ; e, solitary cell j /, the 
 same, further magnified, showing process of subdivision ; g, 32-celled 
 family; h, small family undergoing division; i, 16-celled family 
 divided into sixteen daughter families. All after Stein X about 500. 
 
 Genus 42. GOHIVU. Muller. (1873.) 
 
 Coenobium quadrangular, tabular, angles rounded, formed 
 from a single flat stratum of cells, girt by a broad hyaline 
 plano-convex tegument. Cells 16 (central 4, peripherical 12 j, 
 polygonal, bright green, becoming with age disordered, granu- 
 lose, connected by the produced angles, chlorophyllose vesicle 
 central, furnished with colourless contractile vacuoles, and two 
 long exserted cilia. 
 
 Propagation by repeated division of the cytioplasm. 
 
70 COCCOPHTCE^. 
 
 Gonium pectoxale. JUull. Vermiam,p. 60. 
 
 Coenobium flattened, quadrangular, composed of 16 green 
 cells, furnished with vibratile cilia. 
 
 Size. Coenobium, from -05 mm. Cells from -01 X "007 mm. 
 
 Eabh. Alg. Eur. iii. 99. Miill. Anim. Inf. t. 16, f. 9-11. 
 Ehrb. Infus. 56, t. 3, f. 1. Dujard. Zoophy. p. 318. Focke 
 Studien, 30, t. 4, f. 7, 8. Fresen, Abhand. der Senck, p. 191, 
 t. 8. Cohn Nova Acta, xxiv. p. 169, t. 18, f. 9-27. Prit- 
 chard Infus. p. 518. 
 
 In stagnant water. 
 
 The fullest acoonnt of Gonium is that by Cohn, pnblished many years 
 ago, bnt nothing has been added to its history since. The following is a 
 summary of his observations : — 
 
 ' Each family is invested with a colonrless mucous sheath which is diffi- 
 cult to be seen without adding some colouring matter to the water, as 
 there appears to be no tegument. Seen from above, it is a quadrilateral 
 tablet with rounded corners, or from the side elliptical. The primordial 
 cells are sixteen in number, four occupying the centre disposed as a 
 square, and three on each side external to these. The central cell of the 
 three on each side is seta little nearer towardsthe centre. The cells are 
 somewhat polygonal, the four central being hexagonal, and the twelve 
 external pentagonal. When young the angles can scarcely be dis- 
 tinguished. This regular polygonal form indicates that each cell is sur- 
 rounded by a firm membrane, which retains them in a iixed form. The 
 investing membrane may also be detected at the angles of the cells, from 
 each of which it is extended in a short tubular process, which is quite 
 colourless. These processes are joined to those of contiguous cells, so 
 as to link them all together. These processes are not visible in imma- 
 ture families, being subsequently developed. 
 
 In other points the organization of the cells resembles Ohlamydomonas. 
 Their contents consist of protoplasm, coloured by chlorophyll, when old 
 containing numerous corpuscles, a central darker corpuscle, and often 
 several vacuoles. Each cell is furnished with two cilia, which proceed 
 from the protoplasm, through perforations in the cell wttU. 
 
 The movements of the coenobium resemble those of Stephanospli(Bra ; 
 it revolves on its short axis, so that its polar aspect is that of a rotating 
 surface, whilst its equatorial is linear. 
 
 In the development by subdivision only the cell-contents are con- 
 cerned. The fission takes place by four successive stages, or genera- 
 tions, in each of which bisection of the cells occurs, so that ultimately 
 each primordial cell is subdivided into sixteen portions. When the sub- 
 division is completed by the construction of these sixteen small cells, 
 they are seen to occupy the same position and arrangement in the 
 mother-cell as in the parent coenobium. 
 
 The primordial cells of the newly formed coenobia appear unconnected 
 with each other. The movement of the parent coenobium continues 
 until the last stage of fission is completed, when it ceases, and the 
 young daughter coenobia commence a movement within the parent cell, 
 sometimes appesiring as a disc, and at others as a line, according as the 
 surface or the edge is turned towards the spectator. 
 
 At length the mother-cell ruptures, and the young colony escapes into 
 the water, moves about freely, and starts on an independent existence. 
 Supposing that a young Gonium after twenty-f onr hours is capable of 
 development by fission, it follows that, supposing the conditions favour. 
 
VOLVOOINB^, 71 
 
 able, a single colony may on the second day develop 16, on the third 
 256, on the fourth 4,096, and at the end of the week 268,435,456 other 
 organisms like itself. 
 
 It has been snppoaed that some of the cells become detached from the 
 mature oceuobium and pass into a resting condition, but this has not been 
 positively demonstrated, so that ilssuration is the only mode of repro- 
 daction at present known. 
 
 A fuller abstract of this paper by Cohn (from " Nova Acta," "Vol. 
 XXIV., p. 169; is given in Pritchard's Infusoria (p. 153). 
 
 Plate XXVII. fig. 1. Qonium pectorale — a, i, c, families in difEereut 
 positions X 400 ; d, e, the same, rather more highly magnified ; /, family 
 before division ; jf, family of 16 cells divided into 16 daughter families; 
 dtog after Stein. 
 
 Genus 43. STEFHANOSFKiERA. Cofm. (1852.) 
 
 Coenobium throughout its whole life rotating and moving, 
 composed of 8 green cells, bearing two vibratile cilia, disposed 
 at eqiial distances around a circle, enclosed in a common 
 colourless hyaline, globose vesicle. 
 
 Propagation, both by macrogonidia arising from the eight- 
 fold division of the green cells, bearing two cilia, with a lateral 
 red spot, congregated in families of eight ; and by microgonidia, 
 very much smaller, produced by multiplied division, at first re- 
 volving within the common vesicle by the action of four cilia, 
 afterwards free, escaping singly, 
 
 Stephauospheera pluvialis. Cohn Bednngia i.,p. 11. 
 
 Cells globose, elliptic or fusiform, often at each extremity 
 spreading out in mucous rays. 
 
 Size. Coenobium •026--052 mm. Cells •006--012 mm. 
 diam. ' 
 
 Eabh. Alg. Eur. iii. 100. Currey in Micr. Journ., 1858, vi. 
 p. 131, t. 6, f. 1-27. Cohn Zeitschr. fur Wiss. Zool., 1852, 
 iv. p. 77. Archer Micr. Journ., 1865, p. 116. Pritchard Inf. 
 p. 529, t. 19, f. 38-58. 
 
 In hollows of rocks, and in pools aifter rain. 
 
 Stephanosphtsra was first observed in 1850 in Germany, and since in 
 many places, including the British Isles. 
 
 It consists of a hyaline globe, containing eight green primordial cells, 
 arranged in a circle in its equator. The globe rotates upon an axis per- 
 pendicular to the plane in which the primordial cells are arranged, and 
 moves actively in space by the aid of cilia, two of which proceed from 
 each of the primordial cells, and pierce the hyaline envelope. The 
 primordial cells divide first into two, then four, and lastly into eight 
 portions ; these portions separate from each other in a tangential direc- 
 tion, thus forming a disc round which a cellular membrane is developed. 
 Two cilia are produced upon each segment, and thus eventually eight 
 young individuals are formed, which ultimately escape by fissure of the 
 
72 
 
 COCCOPHTCE^. 
 
 paxent globe. This process was observed to oocnpy abont twelve boitrs. 
 Cobn also observed the division of each of the eight primordial cells into 
 a great mnnber of microgonidiaj which swarm within the globe, and 
 escape from it. Under certain circamstances each of the eight cells 
 secretes a cellular covering, and swims abont in the interior of the 
 globe in the form of free Chlamydococcus-]ike cells. Eventually they 
 escape either by fissure of the globe or by its gradual dissolution, lose 
 their cilia, form a thicker membrane, become motionless, and accamu- 
 late at the bottom of the vessel. If the vessel be permitted to become 
 dry, and afterwards filled with water, motile Stephanosplusra reappear, 
 from which it seems probable that the green globes are the resting cells. 
 
 The resting cells vary much in size, and it is supposed that they 
 grow considerably after attaining a state of rest. The colour is deep 
 green, sometimes yellowish or olive, and they possess a nacleus. 
 
 The dried resting spores absorb water, and their contents gradually 
 fill up the cavity of the containing membrane, and become clondy and 
 granular ; the border becomes yellowish, and the red colouring matter is 
 contracted in the centre. The cells then begin to divide and pass 
 through successive stages, as shown on the plate (Plate 28, figs. 13 
 to 17). The four daughter-cells begin to quiver, and endeavour to 
 separate from each other. Two cilia are now apparent at the pointed 
 extremity of each of the four cells (fig. 19), by the action of which the 
 group begins to move as a whole ; ntlimately all trace of the enveloping 
 membrane disappears, and one by one the daughter-cells escape and 
 become free. At the moment of escape their diameter never exceeds 
 •01 mm., but they soon enlarge to a diameter of '013 to ■015 mm. 
 
 The length of time which elapsed between the immersion of the 
 dried resting spores and the first appearance of the motile cells varied 
 from nine to twenty-four hours. It was observed that those resting 
 spores which did not prodnce zoospores within six days never did so 
 afterwards, although they continued to live, and seemed perfectly 
 healthy. Zoospores produced in November did not advance beyond the 
 first stage. Others produced in March remained only a few hoars in 
 that condition, after which time a delicate membrane was formed 
 round the body of the primordial cell ; this membrane was at first 
 closely attached to the cell, but became gradnaJly enlarged, by absorp- 
 tion of water, into a colourless enveloping vesicle, nsnally globular, 
 but sometimes oval, having two openings, through which the cilia 
 penetrate. In this condition they attain a diameter of "017 to '022 mm., 
 and are not distinguishable from encysted forms of Chlamydococcus 
 pluvialis. Other zoospores, prodaced in April, attained a larger size, 
 and the protoplasm of the primordial cell, instead of retaining its con- 
 tinuous outline, became elongated here and there into simple or forked 
 mucilaginous rays, which were either colourless or green from the presence 
 of chlorophyll. These rays are probably produced by the protoplasm ad- 
 hering at certain points to the surrounding membrane, and being carried 
 outwards by its growth. The Chlamydococcus-like form only lasted a 
 few hours ; towards the evening the zoospores mostly began to divide. 
 The rays are drawn in, the primordial cell becomes round, it then elon- 
 gates, is constricted, and ultimately is divided into four quadrants. 
 These are again bisected, and eventually eight wedge-shaped portions are 
 formed, whose contour lines, like the spokes of a wheel, meet in the 
 middle. 
 
 Here is to be noted a distinction between the St/fpharwsphtera and 
 Chlamydococcus; for while in tte latter the individual portions of a 
 primordial cell separate entirely from each other, each developing its own 
 enveloping membrane, and ultimately escaping as a unicellular indi- 
 vidual, in the former the eight portions remain united as a family. The 
 
VOLVOOINEiE. 73 
 
 coloured contents of the Individual portions become drawn back towards 
 the periphery in centrifugal direction, a colourless plasma remaining 
 about the central point ; this disappears at first in the centre, a cavity is 
 formed in the middle of the disc, and as this enlarges the eight portions 
 assume the form of a vfreath, consisting of eight globular or ellipsoid 
 bodies in close contact, usually not exactly in one plane, owing to the 
 outer membrane not having expanded in proportiou to the enlargement of 
 the plasma. The original cilia continue active, causing the motion of 
 the whole organism, until the eight portions are completely individualized , 
 and then their motion ceases. The separate parts of the plasma now form 
 eight independent but closely packed membraneless primordial cells. 
 t-hortly afterwards a delicate membrane common to them all is secreted 
 beneath the mother-cell membrane round the disc formed by the primordial 
 cells. This membrane is at firstin contact, but afterwards becomes further 
 and further removed as it swells and tends to assume a globular form. By 
 the motion of the cilia the mother-cell membrane is thrown off, and the 
 young family escapes into the water. When the Ohlamydococcus-like 
 unicellular Siephanosphoera has commenced its division early in the 
 evening, the division into eight is perfected during the night, and early 
 in the morning the young family quits its cast off mother-cell membrane. 
 In the course of the day the individual primordial cells and their 
 common invescing membrane grow until the latter attains a diameter 
 -of "01 to '048 mm. During this growth the shape of the primordial 
 cells is changed by the formation of various prolongations, but in the 
 course of the afternoon they again become round, and during the even- 
 ing division commences in them precisely similar to the process in the 
 nnioellnlar Stephanosphaera. On the following morning we lind eight 
 young families. It is calculated that in eight days, under favourable 
 circumstances, 16,777,216 families may be formed from one resting cell 
 of StephartosphcBra. 
 
 We have given but a barren outline of the history of this little plant, 
 but for further information must refer the student to Cohn's Original 
 Memoir in Siebold and Kolliker's Zeitschrift fur Zoologie, 1852, p. 
 77. Translated in the " Annals of Natural History," 2nd series, Yol. S., 
 pp. 321 and 401. Also Cohn and Wichura's subsequent memoir " Ueber 
 Stephanosphsera " in Nova Acta Acad. Leop. Car., 1857, part I., Vol. 
 XXVI. Of which an abstract is given by Uurrey in " Quarterly Journal 
 of Microscopical Science," Vol. VI. (1858), p. 131. Also an admirable 
 summary by Archer in the " Quart. Journ. of Microscopical Science " 
 for 1865, p. 117, with additional observations by himself. 
 
 Plate XI.7II1. fig. 1. Polar view of family with globose primordial 
 cells; 2, equatorial view, with fusiform primordial cells ending in 
 mucous filaments ; 3, the same, with primordial cells collected on one 
 side ; 4, commencement of formation of macrogonidia ; 5, all eight pri- 
 mordial cells divided in fours ; 6, division advancing so that each 
 primordial cell consists of eight cuneate segments ; 7, further advanced 
 in division, movement in the mother-cell having commenced ; 8, 
 division completed, eight young individuals revolving in the mother- 
 cell ; 9, the eight original primordial cells broken up into microgouidia; 
 10, young StephanospluBra, (figs. 1 to 10 X 300) ; 11, microgouidia after 
 exit from mother-cell X 500 ; 12, full-grown resting cells ; 13, commence- 
 ment of division in resting cell ; 14 to 19, successive stages in division 
 of resting cell ; 20 to 22, naked zoospores j 23, 24, encysted zoospores ; 
 25 to 27, division of encysted zoospores ; 28, young eight-celled family 
 resulting from division of encysted zoospore ; 29, 30, young families, 
 all after Cohn X 400 j 31, amseboid condition of primordial cells, after 
 Archer. 
 
74 ZYGOPHYCBiE. 
 
 Order II. ZYGOPHTCE^. 
 
 Either unicellular or multicellular Algae, with terminal vege- 
 tation, and destitute of true ramification. Cells single, or 
 segregate, or geminate, or united in a series. Chlorophyll-mass 
 for the most part distributed in plates, or bands, including one 
 or more amylaceous granules. 
 
 Multiplication by division of the cells in one direction. 
 
 Propagation by zygospores resulting from the conjugation of 
 two cells. 
 
 Consult here Dr. A. De Bary's " Uutersuoliungen uber die Familie 
 der Conjugaten." Leipzig, 1858. 
 
 Family L DBSMIDIB^. 
 
 Unicellular Algae. Cells for the most part compressed, 
 single, or segregate, or geminate, or a larger number united in 
 a band, or filament ; variable in form, usually constricted in the 
 middle, so as to constitute two symmetrical semi-cells. 
 
 This large and interesting family is designedly excluded from the 
 present work, as it is proposed to treat them separately. As so many 
 stndents confine themselves exclusively to this family, this proposal 
 will doubtless commend itself. The excellent text book by J. Ralfs haa 
 long been the standard for English students, and would be so still but 
 for its scarcity, and the large number of additions in the interval since 
 its publication. 
 
 Family IL Z YGNEMACB JE . 
 
 Multicellular Algae. Cells cylindrical, equal at both ends ; 
 fructiferous cells more or less tumid, or inflated, all closely 
 conjoined in filamentous families, forming an articulated simple 
 thread, with a centml cytioblast involved in radiating proto- 
 plasm. Cell walls lamellose. 
 
 Chlorophyll-mass effused, or of a definite form, often forming 
 a spiral band. 
 
 Vegetation by repeated transverse division. 
 
 Propagation by zygospores, resulting from the conjugation of 
 two cells. Conjugation taking place in three ways, lateral, 
 scalariform, and genuflexuous. 
 
 This family is sub-divided into three sub-families, according to the 
 character of the reproductive process : — 
 
 I. ZlGMEME^. 
 
 II. Mksocabpe^, 
 
 III. GONAIONEME^. 
 
ZYGHEMACE.E. 75 
 
 We append here De Baxy's soheme of classification of this Order, 
 which he terms " OonjugatEe." 
 
 " Cells of limited growth, propagated by unlimited repeated biparti- 
 tiou (tripartite in Oraierospermum) in the same direction, free or con- 
 nected in single rows, chlorophyll in parietal bauds, axile plates, or 
 radiating bodies, in pairs. Cell-wall cellulose or gelatinous. 
 
 " Fructification. By copulation a zygospore arises of a different form 
 from its mother-cells. No asexually produced swarmspores. 
 
 " Subdivisions. 
 
 " I. Mesocarpeis. Zygospore the shape of the mother-cells, not con- 
 tracted, separating by three or five partitions into a central firm-walled 
 resting-spore and two or four lateral decaying cells. (Cells cylindrical, 
 united in threads, with axile plates of chlorophyll.) 
 
 " II. Zyg'n,eme(e. Zygospore undivided and mostly contracted, passing 
 into the resting condition, afterwards developing into a germ-cell divided 
 into a basal cell, and a thread-cell capable of division. (Cells cylin- 
 drical, united in threads.) 
 
 " III. Desmidiece. Zygospore of the form of the Zygnemece, develop, 
 ing into a germ-cell, or divided into 2 or 4, each of which separates into 
 two equal daughter-cells capable of division. (Cells usually consisting 
 of two symmetrical halves, of very various form, free or United.)" 
 
 We have adopted a similar arrangement, with the exception of the 
 present exclusion of the Desmidiece, and the addition of a small sub- 
 family, the GonatoTiemeiB, which dates from a period subsequent to 
 De Bary's Memoir. 
 
 Conjugation in the present family is the union of two cells, either of 
 separate filaments, or of the same filament, the result being the forma- 
 tion of a zygospore. The cells containing the male and female element 
 cannot at present be distinguished from each other, although De Bary 
 states that he has observed a constant difierenoe between the fertile and 
 sterile cells of a species of Spirogyra. Usually all the cells of one 
 filament appear to be either giving or receiving cells, so that the male 
 and female filaments would seem to be distinct, but this requires more 
 certain confirmation, inasmuch as in such of the species of Sj)irogyra as 
 exhibit lateral as well as soalariform conjugation, all the cells in one 
 filament cannot be of the same kind. 
 
 " The first perceptible change in a cell about to produce a resting- 
 spore appears to be a loosening of the primordial utricle from the outer 
 wall, and a contraction of it upon the cell-contents, which thus are 
 crowded together and more or less deformed. Simultaneously with 
 this, or a little after or before it, the side wall of the cell is ruptured, and 
 a little puUnlation or process is pushed out, which directly coats itself 
 with cellulose and rapidly enlarges to a considerable diameter, at the 
 same time growing in length until it meets a similar process pushing out 
 from an opposing cell, or has attained as great a, length as its laws of 
 development will allow. When two processes meet they become fused 
 together, the end walls are ruptured, and the contents of one cell pass- 
 ing over are received within those of the other, or else the contents of 
 both cells meet within the connecting tube, and there fuse together. 
 This is the more common mode of conjugation, in which two cells of 
 distinct filaments become joined together by a connecting tube. It is 
 evident that, if the filaments are fertile to their fullest extent, there 
 will be as many of these connecting tubes as there are pairs of cells 
 in the filaments, and a ladder-like body will be formed, the ori- 
 ginal filaments corresponding to the side pieces, the connecting tubes 
 to the rounds. Hence this method of conjugation has received the 
 name of sealariform. 
 
 " In the so-called lateral conjugation, instead of cells of different 
 filaments joining, adjacent cells of one filament unite together to com- 
 
 M 
 
76 ZTGOPHYCE^, 
 
 plete the process. The nnion of the two cells appears to take place in 
 several ways. In accordance with one plan, connecting tabes, pushed 
 ont from near the ends of the cells, grow for a short distance nearly at 
 right angles to the long axis of the filaments, and then bend at a right 
 angle to themselves, so as to run parallel to the filament cells. The ends 
 of these processes are, of conrse, opposed to one another, and coming in 
 contact, f ose together so as to form a continnons tnbe for the passage of 
 the endochrome. Another method by which neighbonring cells are 
 sometimes connected is by the formation of coadjacent ponoh-like en- 
 largements of the opposing ends, and a subsequent fusion of these 
 newly-formed enlargements by the absorption of the end wall between 
 them." 
 
 " There is still another method of conjugation, the so-called gemijlexu- 
 ows, in which, instead of a connecting tube being formed as the medium 
 of union, two cells of opposing filaments become sharply bent back- 
 wards, so that their central portions are strongly thrust forward as 
 obtuse points, which, coming in contact, adhere, and allow of a passage- 
 way between the cells being made by the absorption of their cohering 
 walls."— TVooifs Jl Water Algoe, p. lei. 
 
 Hafisall says that the conjugation in Zygncemaceae results in the pro- 
 duction of " a dark body, of either an oval or circular form, and en- 
 veloped in membrane, which Taucher, Decaisne, and Jenner regard as 
 the true spores, but which Agardh declares resolve themselves after a 
 time into zoospores, an opinion in which I concur, applying the term 
 sporangia to them." It need scarcely be added that this view is erro- 
 neous, the resulting body germinating direct after a period of rest, and 
 termed a zygospore. ■> 
 
 The same author makes also another statement, rather vaguely stated, 
 which is not confirmed by experience. " It is curious to remark that 
 the cells in one part of the same filament will part with their contents 
 £md remain empty, while in another they will be the recipients of the 
 contents of the cells of another filament." His remarks on agames- 
 sporous Oonjngatie will be illustrated under the sub-family Oonatonemea, 
 
 Sub-Family 1. ZTGNEME.a;. 
 
 Cells cylindrical, united in threads. Zygospore undivided, 
 and mostly contracted, passing into the resting condition, after- 
 wards developing into a germ-cell, divided into a basal cell, and 
 a thread-cell, capable of division. 
 
 As hereafter explained, this sub-family differs from the Metocarpece 
 chiefly in the development of the spore, which is not surrounded, or 
 accompanied, by two to four deciduous lateral cells. 
 
 Genus 44. ZTGNEMA. Kutz. (1843.) 
 Cells with two axile many-rayed chlorophyll bodies standing 
 near the central cell nucleus, each containing a starch-granule, 
 or quite filled with dense granular contents, surrounding two 
 starch-granules lying near the centre, (a) zygospore in the 
 bladdery middle space between the ladder-like united pairing 
 cells (J), copulation ladder-like, or lateral between two cells 
 of the same thread. 
 
ZYGNKMACBJB. 77 
 
 In certain of the species of this genus the zygospores are produced in 
 the oonjngating canal, and in other species in one or other of the con- 
 jugating cells. This fact is taken advantage of in the following arrange, 
 ment : — 
 
 A. Zygospores produced jn conjugating canal. 
 
 * Sporoderm scrobiculate, 
 
 1. Zygnema peotinatum, Aff. 
 
 ** Sporoderm even. 
 
 2. Zygnema Ealfsii, Kutz. 
 
 3. Zygnema parvulum, Kutz. 
 
 B. Zygospores produced in one or other of the conjugating cells. 
 
 * Sporoderm, pwnctate, 
 
 4. Zygnema crnciatnm ( Vauch.). 
 
 5. Zygnema atellinum (Vauch.). 
 
 6. Zygnema Vancherii, Ag. 
 
 7. Zygnema anomalum (Hass.). 
 
 ** Sporoderm even. 
 
 8. Zygnema leiospermnm, DeBory. 
 
 9. Zygnema insigne, Kutz. 
 
 A. Zygospores produced in conjugating canal. 
 Zygnema pectinatum. ^g. Sytt. p. 78. 
 
 Sterile cells 1-2 times as long as broad. 
 
 Zygospoi-e globose or broadly elliptic, dark olire, scrobicu- 
 late, formed in the canal of conjugation. 
 
 Size. Cells "OS-'OSS mm. diam. (sometimes less), zygospore 
 ■04 mm. diam. 
 
 DeBary Conj. p. 77, t. 1, f. 15; 19, t. 8, f. 13. Gray 
 Arr. i. 1296. 
 
 Gonjugata pectinata, Vauch. Conj. p. 77, t. 7, f. 4. 
 
 Conferva hipunctata, Eng. Bot. t. 1610. 
 
 Conferva decussata, Dillw. Conf. Syn. p. 5, (?) 
 
 Zygogonium pectinatum, Eabh. Alg. iii., 252. Kirsch. Alg. 
 Schl. p. 126. 
 
 Tyndaridea conspicua, Hass. Alg; t. 39, f. 1, 2, Ann. Nat. 
 Hist, xii., 187, t. 7, f. 17. 
 
 Tyndaridea immersa, Hass. Alg. t. 39, f. 3. Ann. Nat. Hist, 
 xii. 188, t. 7, f. 19. 
 
 Tyndaridea decussata, Hass. Alg. t. 39, f. 6. Ann. N. Hist, 
 xii., 188, t. 7, f. 18. 
 
 Zygogimium conspicuum, Kutz. Tab. v. t. 12, f. 2. 
 
 Zygogonium immersum, Kutz. Tab. v. t. 12, f. 5. 
 
 Zygogonium decussatum, Kutz. Tab. v. t. 11, f. 4. 
 
 Tyndaridea pectinata, Eng. Fl. v. p. 361 ; Eng. Bot. ii. t. 
 2597, Harv. Man. 142 ; Mack. Hib. 231. 
 
 Zygnema hipunctatum, Grey. Fl, Ed. 320 ; Fl: Devon, ii. 50. 
 
 In still waters. 
 
 As noted ahove, we include here three of Hassall's species of Tynda- 
 ridea^ Sirschuer does the same, with the addition of Kutzing's Z a/m- 
 
78 ZYGOl'HYCE^. 
 
 malum, which, however, is not the Tyndaridea anomala of Haifa and 
 Hassall, as will be evident hereafter. There does not seem to be even 
 a sufficient difference to justify the maintenance of the different forms 
 as varieties. This is the only British species, as far as at present known, 
 with a scrobioulate zygospore, produced in the channel of conjngation. 
 We have followed De Bary in referring this species to Zygneina instead 
 of to Zygogonium. It is unnecessary in a work of this kind to discuss 
 the reasons which have induced ns in this, and similar cases, to adopt 
 such a course. It may be well to caution the student at once that he 
 will only waste time in the endeavour to determine species from the 
 sterile threads. In the present, for instance, he would soon discover 
 how hopeless it is to attempt to discriminate between the vegetative 
 cells of this and some of its allies, without the knowledge also of the 
 method in which the zygospore is formed, and its character when de- 
 veloped. 
 
 Jtee XJLIX.. fig. 1. a, portion of sterile thread X 400 ; h, threads 
 in conjngation x 200; e, zygospore X 400. 
 
 Zygneina Ralfsii. (Kviz^ BeBa/ryConj.p.'n. 
 
 Sterile cells 2^ to 3 (rarely 4) times as long as broad. 
 
 Zygospore compressed ellipsoid, twice as long as broad, 
 produced in tbe inflated conjunctive canal. Sporodenn even. 
 
 Size. Cells •016--017 X •02mm. Zygospore -025 X -015 mm. 
 
 Eabh. Alg. Eur. iii. p. 252. 
 
 Zygogonium Ralfsii, Kutz. Tab. v. t. 11, f. 2. Kirsch. Alg. 
 Schl. p. 127. 
 
 Tyndaridea Ralfsii, Hassall Alg. p. 165, t. 39, fig. 4, 5. 
 
 Ann. Nat. Hist. xii. p. 188, t. 7, f. 20. Jenner Fl. Tunb. 
 Wells, p. 182. 
 
 In pools and streams. 
 
 This is the only other British species of Zygnema in which the zygo- 
 spore is produced in the channel, except the succeeding one, which is at 
 best doubtful. It appears to be uncommon, at least in conjugation. 
 First found by Mr. Balfs at Penzance. It is still to be obtained in its 
 old habitat, and it appears to have been discovered in IVanoe and Gfer- 
 many. 
 
 From the brief note of De Bary, he seems to recognise this as a dis. 
 tinct and veritable species of Zygnema, according to his interpretation of 
 that genus. 
 
 Plate XXIX.fig. 2. a, portion of sterile thread X 400; h, threads 
 in conjugation X 400. 
 
 Zygnema parvulam. (Kutz.') 
 
 Sterile cells 4 to 6 times as long as broad, zygospore globose, 
 produced in the conjunctive canal. 
 
 Size. Cells •02--022 mm. Zygospore about equal. 
 
 Zygogonium parvulum, Kutz. Tab. v. t. 12, f. 4. Kutz. Sp. 
 Alg. p. 447. 
 
 Zygnema ordinarium, Berk. Glean. 1. 12, f. 1. Harv. Man. 144. 
 
 In standing pools. 
 
 If the Zygnema ordinarium of Berkeley's " Gleanings " can be re- 
 ferred to Zygnema parvulum, that is, as far as we have ascertained. 
 
ZYGNKMAOEJ!. VD 
 
 the whole evidence upon which this species is inserted. The figure in 
 the " Gleanings," as represented, in part, on onr plate 29 (fig. 3o), is so 
 manifestly insufficient, without measurements, that the species is intro- 
 duced with some hesitation. The rest of our figures, and the descrip- 
 tion, are derived from Continental sources, and represent Kutzing's 
 
 Berkeley says of the plant he has figured : — " The filaments are 
 quite unattached, and float in a rather dull green mass at the top of the 
 water, which (at least in a state of fructification) is but little mucous, 
 adhering imperfectly to paper in drying. But as the plant has only been 
 once met with, and it is well known that other species of Zygnema are 
 much less mucous in a state of fructification, it is uncertain whether 
 this is peculiar at all to the species. Articulations 4 to 6 times as long 
 as broad, at first filled with a yellowish green sporaceous mass, without 
 any marked pellucid border, with a single row in the centre of from 5 to 
 7 larger granules. The mass at length contracts, and the row of granules 
 is no longer visible. Short tubes are thrown out from the centre of the 
 joints, by which the filaments are at length connected into a more or less 
 intricate mass, and in the tubes a globular seed is formed, which swells 
 them, and is furnished with a pellucid border. In general the spora- 
 ceous matter of only one articulation passes into the tube to form the 
 seed ; nor in such case does the joint, of which the contents still appear 
 unaltered, throw out another tube. Found at Glapthorn, Northampton- 
 shire, in the spring of 1826, in watery spots of an exposed, ill-drained 
 field." 
 
 Plate XXIX. Jig. 3. a, portion of sterile thread X 400 ; b, 
 threads in oonj ugation X 200 ; c, conjugating cells and zygospores of 
 Zygnema ordinarium, after Berkeley, magnification unknown, 
 
 B. Zygospores produced in one or other of the conjugating cells. 
 Zygnema czuciatam. (_Vaiich.) 
 
 Sterile cells equal or twice as long as broad. 
 
 Zygospore sphEerical, formed in one or other of two conjoined 
 cells. Membrane brown and scrobiculate. 
 
 Size. Cells -028 mm. broad. Zygospore -04 mm. diam. 
 
 Cleve Mon. Zygn. p. 29, t. 9, f. 1-3. Kirsch. Alg. Sohl. p. 
 126. Kutz. Tab. Phy. v. t. 17, f. 4. 
 
 Conjugata cruciata, Vauch. Hist. Conf. p. 76, t. 7, f. 2. 
 
 Tyndaridea cruciata, Hass. Alg. 160, t. 38, f. 1. Eng. Bot. 
 Ed. 2, t. 2512 B. Eng. Fl. v.p. 361. Mack, Hib. 231. 
 
 Conferva bipunctata, Dillw.Conf. t. 2. Hook Fl. Scot, ii, 81. 
 
 Zygnema bipunctatum, Johnst. Fl. Berw. ii, 256. Gray Arr. 
 i, 296. 
 
 Zygnema Dillwyni, Kutz. Tab. Phy. v. t. 17, f. 
 
 In ditches, pools, &c. 
 
 The form figured by Dillwyn is more slender than the typical form 
 and ia considered by some as a distinct variety. 
 
 There is, perhaps, some difficulty in determining the exact limits of 
 the three species L. cruaiatum, L. stellinum, and L. Vavxiherii, unless by 
 merging the latter two in one, and accepting Z. cruaiatum as possessing 
 globose zygospores, whilst the other species has oval, or somewhat elon- 
 gated zygospores. 
 
 Plate XXX. fig. 1. a, portion of sterile thread X 400; b, conjugat- 
 ing threads with zygospores X 200 ; c, mature zygospore X 400. 
 
so ZYGOPHYCE^. 
 
 Zygnema steUinnm. (Vouch.') Kvts. Tab. V.t.Vl,f.2. 
 
 Sterile cells 1^ to 3 times longer than broad. 
 
 Zygospore broadly ovoid, formed in one or other of the con- 
 joined cells. Membrane brown, scrobiculate. 
 
 S poriferous cells commonly longer than the zygospore. 
 
 Size. Cells -022 mm. Zygospore "04 x '03 mm. 
 
 De Bary Conj. p. 78. Cleve Mon. Zyg. p. 28, t. 8, f. 9-11. 
 Eabh. Alg. Eur. iii, 249. 
 
 Conjugata stellina, Vauch. Conf. p. 75, t. 7, f. 1. 
 
 Thwaitesia Duricsi, Mont. Fl. Alg. t. 15, f. 1. 
 
 Tyndaridea stellina, Jenner Fl. Tunb. Wells, p. 182. 
 
 In pools and ditches. 
 
 Kirscliner nnites this species and the next, for which he appears to 
 have great justification. We scarcely see how they can be maintained 
 as distinct if the broad view of Zygyisma Vaucherii which we have 
 adopted is tenable. 
 
 No definite period can be fixed for the prodnction of the zygospores, 
 not only in this species, but in the majority of the Zygnemaceos. We 
 have observed them in Jnne, or earlier, some as soon as April, and as 
 late as September. Hassall says " the species may be fomid in a state 
 of conjugation dnring the entire of the spring, summer, and autumnal 
 months; they are chiefly met with, however, in this state in the 
 spring." Cleve has attached dates to the species enumerated by him, 
 but a« these do not correspond with the periods at which we have found 
 them in this country, these dates are not quoted lest they should prove 
 misleading rather than useful. 
 
 Plate XXX. fig. 2. a, portion of sterile thread X 400 ; b, oonjugat- 
 ing threads and zygospores X 400. 
 
 Zygnema Tanchexii. Aff. Syst. Alg. p. 77. 
 
 Sterile cells 2^ or 3 to 5 times as long as broad. 
 
 Zygospores subglobose or broadly elliptic, produced in one 
 or other of the conjugating cells, which is usually more or less 
 inflated, sporoderm delicately punctate. 
 
 Size. Cells •01-"022 mm. Zygospore, according to the 
 varieties. 
 
 Eabh. Alg. Eur. iii. 250. 
 
 Conjugata gracilis, Vauch. Conf. t. 6, f. 2. 
 
 Tyndaridea bicornis, Hass. Alg. 162, t. 38, f. 5. 
 
 Tyndaridea interposita, Hass. Ann. Nat. Hist. x. p. 43. 
 
 In ditches, ponds, &c. 
 
 var. a. tenae. Habh. Alg. Evr. iii. p. 250. 
 Sterile cells •019-'022 mm., 1 to 3 times as long. 
 
 var. h. sabtile. Mabh. Alg. Eur. Iii. p. 250. 
 
 SterUe cells •015-'019 mm., 2 to 4 times as long. 
 Tyndaridea ovalis, Hass. AJg. t. 38, f. 8, 
 
ZYGNEMACB^. 81 
 
 vwr. c. stagnale. Kirsoh. 
 Sterile cells 'Ol mm., 3 to 4 times as long. 
 Tyndaridea stagnalis, Hass. Alg. 162, t. 38, f. 9. 
 Tyndaridea stagnicola, Hass. Ann. N. Hist. x. (1842) p. 42. 
 Jenner Fl. Tunb. Wells, p. 182. 
 
 It will be seen from the above that this is a variable species, of which 
 two of the three varieties are British. These are by no means nn- 
 common, often mixed with other filamentons algae, and can scarcely be 
 confounded with anything else, even when sterile. 
 
 Plate XXX. fig. 3. a, portion of sterile thread X 400 j b, portion 
 of fertile thread with zygospores X 400. Fig. 4, var. subtile, a, portion 
 of sterile threads X 400 ; 6, conjugating threads and zygospores X 400. 
 Fig. 5, var. stagnale. a, portions of sterile threads X 400 ; 6, fertile 
 cells with zygospores X 400. 
 
 Zygnema anomalum. {Hass.) 
 
 Sterile cells equal, or nearly twice as long as broad ; cytio- 
 derm thick, lamellose. 
 
 Zygospore globose, olivaceous (sporoderm distinctly punc- 
 tate ?). 
 
 Size. Cells •025 mm. diam., with mucous sheath about 
 double ; zygospore '026 mra. diam. 
 
 Tyndaridea lutescens, Hass. Alg. t. 38, f. 4. Dickie Bot. 
 Guide 296. 
 
 Tyndaridea cruciata, Harv. Man. p. 141. 
 
 Tyndaridea abbreviata, Hass. Aiin. Nat. Hist. x. (1842) p. 48. 
 
 Tyndaridea anomala, Hass. Alg. t. 38, f. 2-3. Jenner Fl. 
 Tunb. Wells, 182. Ralfs, Eng. Bot. Supp. t. 2899. 
 
 In boggy pools. 
 
 The British species is the Tyndaridea anomala of Hassall and Ealfs, 
 and not the Zygnema anomalum of Continental botanists, which species 
 has the zygospore produced in the conjugating canal. The following is 
 the original description published by Balfs in the supplement to " Eng- 
 lish Botany " :— 
 
 " It forms large, dark green masses in shallow pools on heaths. The 
 filaments are stout ; under the microscope each is found to be enclosed 
 in a hyaline sheath, which extends on each side about half the breadth 
 of the coloured portion, and is always more or less waved or scolloped. 
 At first it is nearly even, but it gradually becomes more and more irre- 
 gular, and the conjugating specimens are almost denuded. The joints 
 of the filament are usually about equal in length and breadth, but 
 sometimes twice as long as broad. The endoohrome is blackish green, 
 and at first quadrate, when it completely fills the joint, but its division 
 into two portions gradually becomes apparent until two stelte, but less 
 distinct than those in the other species, are at last developed, when con. 
 jngation takes place in the usual manner. The spores, which are 
 globular, are contained in the joints of one of the connected filaments. 
 Not unfrequeutly the tubular processes are themselves converted into 
 cells containing endoohrome. 
 
 " In its early state this plant is so different in appearance from the 
 other species, that at first sight its proper situation is scarcely appa- 
 
82 ZYGOPHYCE^. 
 
 rent. Indeed, having sent specimens to several celebrated algologists, 
 they hesitated to admit it into T^ndaridea, nntil Mr. Eassall, who also 
 at first strongly doubted whether it belonged to the ConjuffattB, fortu- 
 nately gathered fertile specimens. Such we ourselves found shortly 
 afterwards, and we have since repeatedly met with them ; the appear- 
 ance of the plant in conjugation, however, is so altered that its identity 
 can only be determined by tracing it through aU its changes. 
 
 " In its usual state the sheath is very conspicuous, and the dense en- 
 dochrome So fills the cells that the plant looks like a Conferva, the con- 
 tinuity being interrupted merely at the dissepiments. When about to 
 conjugate the sheath has nearly or altogether disappeared, and the en- 
 dochrome is collected into two stellse, leaving the rest of the cell colour- 
 less."— iJa7/i. 
 
 Hassall also found and examined the plant, and figured it with zygo- 
 spores in the cells of the filaments, whereas the Continental species, 
 since the figure by Kutzing, is always described as having the zygospore 
 in the canal of conjugation. There cannot, therefore, be the slightest 
 doubt that the species found by Hassall and Kalfs is quite distinct from 
 that known to Kutzing, Eabeuhorst, and De Bary. Priority certainly is 
 in favour of Hassall's name, and it is the Continental species which must 
 give way, and yield up a name, acquired in error, to its rightful claimant. 
 Onr figures are based on the sketches and drawings by Halfs, with 
 whom we have been in communication on this question. It is absurd to 
 suppose that Balfs and Hassall were both deceived, as well as Mr. 
 Jenner (an admirable observer), to whom the species was undoubtedly 
 known, and finally Mr. Salter in preparing the drawings from the 
 specimens for the " English Botany." Unfortunately we could find no 
 fmit in the specimens which we possess, collected by Balfs forty years 
 ago, nor could we obtain specimens in conjugation from Cornwall during 
 the past spring. 
 
 Plate XXXI. fig. 1. a, b, portions of sterile threads X 400 ; c, 
 fertile cells with zygospores X 400, after Ealfs ; d, conjugating cells X 
 400. 
 
 Zygnema leiospezmuin. De Bary. Sabk. Algte Exs. No. 638. 
 
 Sterile cells equal in length and breadth, or sometimes twice 
 as long. 
 
 Zygospore globose or broadly oval, formed in one of two 
 conjugating cells ; membrane brown, even. 
 
 Sporiferous cells a little swollen. 
 
 Size. Cells -022 mm. diam. Zygospore •023-'03 mm. 
 
 De Bary Conj. p. 77, 1. 1, f. 7-14. Eabh. Alg. iii. 249. Kirsch. 
 Alg. Schl. p. 125. 
 
 In ditches filled after rain. 
 
 The two British species with the membrane of the zygospore even, 
 in this section, are the present and the following, which will require 
 some care in the discrimination. The inflated cells, which enclose the 
 zygospores, in the present, is relied upon as one of the features which 
 distinguish it from the succeeding species, as well as the larger size of 
 the zygospores. 
 
 Plate XXXT. Jig. 2. u, portion of fertile thread X 400; b, e, 
 fertile cells, with zygospores, after De Bary X 400 ; d, mature zygospore 
 X 400, after DeBary. 
 
ZYGNBMACE^. 83 
 
 Zygnema insigne. Kvtz. Tab. v. t. 17, f. 1. 
 
 Sterile cells equal, or twice as long as broad. 
 
 Copulation scalariform or lateral ; zygospore globose or 
 slightly oval ; membrane brown, even. 
 
 Size. Cells •026-'03 mm. diam. ; zygospore about -026 x 
 ■032 mm., or globose about -03 mm. diam. 
 
 De Bary Conj. p. 78, t. 8, f. 14-16. Rabh. Alg. iii. 249. 
 Kutz. Tab. V. t. 17, f. 1. Kirsch. Alg. 8chl. p. 125. 
 
 Tyndaridea insignis, Hass. Alg. p. 163, t. 38, f. 6, 7. Jenner 
 Fl. Tunb. Wells 182. 
 
 Zygnema tenue, Kabh. Exs. No. 674. 
 
 In streams and ditches. 
 
 The cells of this species at the time of conjugation are apt to become 
 much distorted, inflated sometimes on one side, sometimes on the ofchei*, 
 and even to conjugate in the manner represented by DeBary, and copied 
 on our plate. 
 
 Plate XXXI. fig. 3. a, sterile cells X 400; *, fertile cells with 
 zygospores X 200 ; c, fertile cells, with longitudinal conjugation, X 200, 
 after De Bary ; d, zygospore X 400. 
 
 Genus 45. SPIROGTUA. Unk. (1820.) 
 
 Cells with one to several parietal chlorophyll bands, usually 
 spirally winding to the right. Copulation ladder- like (Spiro- 
 gyra) or lateral (Rhynchonema). Zygospores always within the 
 wall of one of the united cells. Copulating cells similar to the 
 sterile ones, or swollen out. 
 
 This genua, as now accepted, includes two genera as recognised by 
 Kutzii\g, Spirogyra and Uhynchonema. In the former the conjugation 
 was scalariform, and in the latter it was lateral. It is now found that 
 in many species, probably in all, both kinds of conjugation take place, 
 according to circumstances. The same filament, which in some portion 
 of its length conjugates with a neighbouring filament, has also been 
 observed conjugating laterally between two of its own cells. The genus 
 Rhynchonema therefore has thus been proved to represent only one of 
 the modes of conjugation of the same plant, which under other condi- 
 tions conjugates with a neighbouring filament. 
 
 In past times too great importance was attached to the breadth and 
 length of the cells in the sterile filaments, and also to the character of the 
 spiral bands, features which are now known to be too variable to be relied 
 upon, the most important and reliable characters being derived from the 
 zygospore ; hence only specimens in fructification can be accurately 
 determined. 
 
 The most recent work on the species of Western Europe is a Mono- 
 granh of Spirogyra, as represented in France, by Mons. Paul Petit. 
 (Paris, 1880.) See also Professor Cleve's " Monograph of the Zygnemaoese." 
 
 N 
 
84 ZYGOPHYCK^. 
 
 The following is a tabular arrangement of the British species : — 
 Sec. 1. Cells not replicate at the ends. 
 
 A. Chlorophyll bands numerous (rarely two). 
 
 * Spores ovoid or elliptic. 
 
 t Membrane smooth. 
 
 1. crassa, Etz. 
 
 2. jngalis, Sill. 
 
 3. nitida, Lie. 
 
 tf Membrane pnnctate. 
 None. 
 ** Spores orbicnlar. 
 
 t Membrane smooth. 
 
 4. orthospira, Nag. 
 
 +■)• Membrane pnnotate. 
 
 5. orbicularis, Mass. 
 
 6. bellis, Eass. 
 
 B. Chlorophyll bands single or double (rarely tematej. 
 
 * Spore membrane smooth. 
 
 7. porticalis, Yauch. 
 var. a. quinina. 
 
 Chlorophyll bands usually single. 
 var. j8. decimina. 
 
 Chlorophyll bands usually binate, rarely ternate. 
 vwr. f. rivularis, Bass. 
 
 Chlorophyll bands usually three. 
 ** Spore membrane punctate. 
 
 None. 
 N.B. — Spirogyra elongata, Berk. Glean., p. 33, tab. 12, f. 3 (Babh. 
 Alg. iii. 241), would follow here but that the fruit is unknown, and hence 
 it is uncertain. 
 
 0. Chlorophyll bands single. 
 
 * Spore membrane smooth. 
 
 9. condensata, Vauch. 
 9. longata, YaucJi. 
 
 10. flaTOsoens, Cleve. 
 ** Spore membrane pnnctate. 
 
 (N.B. — No record of Sp. velata or 8p. punctata in Britain.) 
 
 Sec. 2. Cells replicate at the ends. 
 
 A. Chlorophyll bands usually two or more. 
 
 * Spore membrane smooth. 
 
 11. Sp. insignis, Sass. 
 ** Spore membrane punctate. 
 
 12. Sp. oalospora, Cleve. 
 
 B. CMorophyU bands single. 
 
 * Spore membrane smooth. 
 
 13. Sp. quadrata, Petit. 
 
 14. Sp. Weberi, Kutz. 
 
 15. Sp. tenuissima, Hoss. 
 
 ** Spore membrane punctate. 
 
 None. 
 
ZYQNEMACB^. 85 
 
 The English student may also consult with advantage a memoir " on 
 the germinatioii of the resting spores in Spirogyra," by Dr. Pringsheim, 
 translated in the Annals of Natural History, 2nd ser., Vol. xi. (1853), 
 p. 210. "On the Structure and Division of the Vegetable Cell," by J. 
 M. Maofarlane, in Transactions of the Botanical Society of Edinburgh, 
 Vol. xiv. (1881). Pringsheim's Researches on Chlorophyll, translated by 
 Professor Bayley Balfour, in Quarterly Journal of Microscopical 
 Science, Vol. xxii., new series (1882). Darwin " On the Action of Car. 
 bonate of Ammonia on Chlorophyll Bodies," in Journal of the Linneau 
 Society, Vol. xix. (1882). 
 
 Section 1. Cells not replicate at the ends. 
 A. Chlorophyll hands numerous {rarely two). 
 
 Spiirogyza crassa. Xutz. 
 
 Sterile cells with the extremities truncate, equal or twice as 
 long as broad. Chlorophyll bands four or more, making -J-l J 
 turns. 
 
 Zygospores broadly and obtusely oval, membrane even. 
 
 Sporiferous cells persistent, not swollen. 
 
 Size. Cells •12--15 mm. diam. (Rabh.), 'IS mm. diam. 
 (Petit), zygospore -li-'lS diam. {Petit), -13 X -12 ; -14 x -12 ; 
 •16 X •12 mm. (if. C.C). 
 
 Zygnema serratuni, Hass. Alg. t. 18, f. 1, 
 
 Spirogyra crassa, Kutz. Tab. v. t. 28, f. 2 ; Kutz. Phy. Gen. 
 t. 14, f. 4 ; Kirsch. Alg. Schl. p. 119 ; Petit Spirogyra p. 32, 
 1. 12, f. 3, 4. 
 
 Spirogyra Heeriana, Kutz. Tab. v. t. 28, f. 3. 
 
 In ponds, &c. Fruiting in summer. 
 
 Hassall says of his Z. serratnm that the " filaments are of nearly the 
 same diameter as those of 2, orticulare, but less mucous, from which 
 species it may readily be distinguished by the fewer number and ser- 
 rated appearance of the spores, the larger size of the granules, and the 
 form of the sporangia, which in Z, orMculare are nearly sphaerical, and 
 compressed, while in Z. serratuvi they are broadly ovate." 
 
 The sterile cells have a greater diameter than any other British 
 species, whilst their length varies from about half a diameter to two 
 diameters. The zygospore is comparatively broader than in S. jugaUs, 
 and slightly flattened, so that when seen in certain positions it appears 
 to be narrower than it is, and more resembling that of 8. jugaUs. 
 
 On plate 32, figs. 1 and 2, the nucleus is represented in the centre of 
 the cells. Pringsheim has recently remarked, as a fact hitherto unre- 
 cognised, that " the threads of the protoplasm extending outwards from 
 the central plasma mass in each cell, do not, as was supposed, end in the 
 general protoplasmic lining of the cell wall, but each passes directly or 
 by its branches to the internal surface of a chlorophyll ba;fid, and there 
 dilates in a trumpet-like manner, and grasps, as it were, an amylum 
 body." — Researches on Chlorophyll, p. 81. '< 
 
 Plate XXXII. fig. 1. a,, sterile cells- X 200 ; I, fertile cells with 
 zygospores X 200 ; c, fertile cells of ShyncTionema form with zygo- 
 spore X 200 ; d, outline of zygospore X 400. 
 
86 ZYGOPHYCi;^. 
 
 Spiiogyza jugalis. (Dill.) 
 
 Sterile cells with the ends truncate, and commonly equal, or 
 double the length of the diameter. Chlorophyll bands 4 to 5, 
 making 1 to 2 turns. 
 
 Zygospore elliptical, membrane even. 
 
 Sporiferous cells not swollen. 
 
 Size. Sterile cells •09--1 mm. diam. (Fetit),-14: mm. diam. 
 (Cleve), -OTS--! mm. diam. {Rabh.), -OS?--!! mm. diam. 
 {Kirsch.^. Zygospores -14 x •1--12 mm. (Cleve), -15 x "1 
 mm. (Petit), -IS-'U X -OSS-'Og mm. {M.C.C.). 
 
 Conferva jvgalis, Dillw. Brit Conf. t. 5. 
 
 Spirogyra jugalis, Kutz. Tab. v. t. 27, f. 2 ; Petit Spirogyra 
 p. 29, 1. 11, f. 3, 4 ; Eabh. Alg. Eur.iii. 245. 
 
 Spirogyra setiformts, Petit Spirogyra, p. 29, t. 11, f. 1, 2 
 fnot Kutz., nor Rabh. Alg. Eur.; : Eabh. Exs. 2292 ; Cleve 
 Mon. Zyg. p. 15 (partly), 1. 1, f. 1-3. 
 
 In clear ponds, &c. Fruiting at Midsummer. 
 
 The British specimens which we refer to this species have the sterile 
 cells from "12 to '14 mm. broad, and abont two diameters long. The 
 zygospore is from 'IS to "14 mm. long and "085 mm. broad. In other 
 specimens, from the Continent, we have fonnd the zygospores from '11 
 to "13 mm. long and '095 mm. broad. M. Petit recognises two species, 
 which he calls respectively S. jugalis and S. setifomiis, differing so little 
 from each other that it seems scarcely possible to distinguish them except 
 in extreme cases. To the latter he refers Z. interruptum of Hassall, 
 but, without the fruit, which Hassall never fonnd, it is difficult to affirm 
 what it might be. It is qnite as probable that it was S. orbieularis as 
 anything else. 
 
 Plate XJXII. Jig. 2. a, sterile cells X 200; b, fertile cells with 
 zygospores X 200; c, outline of zygospore x 400. 
 
 Spizogyxa nitida. {IHllw.) Link Handbk. iii., 262. 
 
 Sterile cells with the ends truncate, and usually 2 to 4 times 
 as long as broad ; chlorophyll bands about 4, making 1 to 4 
 turns of the spiral. 
 
 Spores elliptic ovoid (almost almond-shaped), 1|^ times as 
 long as broad, membrane even. 
 
 Sporiferous cells persistent. 
 
 Germinating plant clavate, radical cell much attenuated. 
 
 Size. Sterile cells •072--078 mm. diam. {Petit), -08-09 
 mm. {Cleve), •06--075 mm. (iJaJL), •054--077 mm. {Eirsch), 
 •07--09 mm. {M.C.C.). Zygospore -1 x •072 mm. {Cleve), -11- 
 •13 X •06--07 mm. {JI.C.C). 
 
 Spirogyra princeps, Cleve Monog. Zygn. p. 16, t. 1, f. 4 to 7. 
 
 Conjugata princeps, Vauch. Conf. p. 64, t. 4, f. 1. 
 
 Zygnema nitidvm, Lyngb. Tent. Hydr. t. 89, f. B. Hass. 
 Alg. t. 22. Harv. Man. p. 143. Eng. Fl. v. 362. Eng. Bot. 
 Ed. ii. t. 2509. Mack. Fl. Hib. 231. Hook. Fl. Scot. ii. 80. 
 Dickie Bot. Guide 296. 
 
ZYGNBMACEiE. 87 
 
 Spirogyra nitida, Kutz. Tab. Phy. v. t. 27, f. 1. Kirsch. 
 Alg. Sciil. p. 123. Petit Spirogyra p. 28, t. 10, f. 6 to 10. 
 
 Conferva nitidum, Dill. Conf. t. 4, f. 0. Eng. Bot. ed. i. t. 
 2337. Jenner Fl. Tunb. Wells 178. Gray Arr. i. 298. 
 
 Zygnema rostratum, Hass. Alg. t. 33, f. 1 . 
 
 In ponds, &c. 
 
 Very little requires to be said of this species, which is the most 
 common one with thick filaments in Britain. It is most probable that 
 Hassall's Zygnema rostratum is the same, conjagating longitudinally, for 
 he says that the filaments are somewhat larger than those of his 
 Zygnema n/iUdmn, but that he had only seen it once. The form of 
 zygospore figured by him is that of the present species, and not of 
 Spirogyra helUs, to which the Rhynchonema rostrata of Kutzing is re- 
 ferred by Cleve. 
 
 Clere proposed to substitute the name of Spirogyra princeps, Vauch., 
 for the universally known Spirogyra nitida, a change with which we by no 
 means sympathise, because, after all, it is only a matter of opinion, and 
 not of demonstration, whether this is really the Conjitgata princeps of 
 Vaucher, and there should be a good and substantial reasons for super- 
 seding a specific name so long recognised as Spirogyra nitida. 
 
 Plate XXXIII. Jig. 1. a, b, sterile cells X 200 ; c, conjugating cells 
 with zygospores X 200 ; d, outline of zygospore X 400. 
 
 Spirogyza orthospixa. Sag. in Kutz. Spec.p. 441. 
 
 Sterile cells with the extremities truncate, and from 2\ to 4 
 to 10 times as long as broad ; chlorophyll bands 3 to 4 to 5 
 (rarely 7), sometimes erect, sometimes forming a very lax 
 spiral. 
 
 Spores orbicular, flattened, membrane even. 
 
 Sporiferous cells scarcely swollen, 2^ to 4 times as long as 
 the diameter. 
 
 Size. Cells •Ob-'Q&b mm. diam. ; zygospore -07 mm. diam., 
 •048 mm. thick. 
 
 Spirogyra orihospira, Archer in Quart. Journ. Micr. Sci., 
 1870. Petit Spirogyra p. 30, t. 10, f. 4, 5. 
 
 Spirogyra majuscula, Kutz. Tab. Phy. v. t. 26, f. 1. Eabh. 
 Alg. iii. 244. 
 
 In pools. Fruiting in autumn. 
 
 This is a recently discovered species in the British Islands, and has 
 hitherto only been recognised by Mr. Archer in Ireland. 
 
 Plate XXXIIl. Jig. 2. a, a, sterile cells X 200 ; b, conjugating 
 cells with zygospores X 200 ; c, front and side views of zygospore X 
 400. 
 
 Spiiogyra orbicularis. Hassall Alg. t. 19. 
 
 Sterile cells with the ends truncate, about equal in length to 
 breadth; chlorophyll bands 5 to 7, making ^ to 1 turn. 
 Zygospores orbicular, flattened, membrane punctate. 
 Sporiferous cells not inflated. 
 
88 ZYGOPHYCE^. 
 
 Size. Cells •ll-'14 mm. diam. ; zygospores "l mm. diam. 
 Narrow diameter "08 mm. 
 
 Petit Spirogyra p. 31, t. 12, f. 1, 2. Kutz. Tab. v. t. 27, f. 
 3. Kirsch. Alg. Schl. p. 118. Rabh. Alg. Eur. iii. 245. 
 
 Zygnema whiculare, Hass. Alg. p. 138, t. 19. Jenner Fl. 
 Tnnb. Wells 178. 
 
 Zygnema alternatum, Hass. Alg. 139, t. 20. 
 
 Zygnema intei-ruptiim, Hass. Alg. 140, t. 21. Ann. Nat. 
 Hist. 1843, p. 432. 
 
 Zygnema maximum, Hass. Ann. Nat. Hist. x. (1842), p. 36. 
 
 Spirogyra altemata, Kutz. Spec. 442. Rabh. Alg. iii. 248. 
 
 Spirogyra setijoj-mis, Kutz. Tab. v. t. 28, fig. 1 (not Petit). 
 Rabh. Alg. iii. 246. Cleve Mon. Zyg. p. 15 (in part). 
 
 In ponds, &c. Fruiting in autumn. 
 
 There is nothing inconsistent in Cleve's suggestion that Hassall's 
 three plat«s 19, 20, and 21 all belong to the same species. Ko reliance 
 can be placed on the width of the chlorophyll bands, nor the little 
 difference in the breadth of the cells. Of course the distnrbance in the 
 bands of the oonjagated cells is dne to the conjugation. When this 
 species is really in frnit there can be no difficulty in its determination, 
 and, without fruit, it is folly to waste time in attempting to guess at the 
 relationship of any species. 
 
 Hassall says that " it is found in ponds and dykes whose waters are 
 deep and permanent, and it does not conjugate until near the end of 
 summer." " Cells when in a state of conjugation, a, little longer than 
 broad, prior to which, however, they are frequently not half so long as 
 broad ; winding round the interior of these are about eight spiral 
 threads, the granules in them being smalL" 
 
 Plate XXXIV. fig. 1. a, sterile cells X 200 ; b, conjugating cells with 
 zygospores X 200 ; c, outline of zygospore X 400. 
 
 Spizogyxa bellis. HassaU. 
 
 Sterile cells with the ends truncate, and usually 1^ times 
 (rarely 3 times) as long as broad ; chlorophyll bands 5 to 6, 
 making ^ to 1 turn, or nearly erect. 
 
 Spores orbicular, depressed, with the membrane punctate or 
 porose, chestnut colour. 
 
 Sporiferons cells persistent, swollen. 
 
 Germinating plant cylindrical, radical cell short and sub- 
 cylindrical . 
 
 Size. Cells •07-"08 mm. ; zygospore •07-'08 mm. diam., 
 •05--06 mm. thick.- 
 
 Cleve Monogr. Zygn. p. 18, t. 3, f. 2 to 5. Petit Spir. p. 
 31, t. 10, f. 1 to 3. 
 
 Zyqnema bella, Hass. Alg. p. 142, t. 24. Ann. Nat. Hist. 
 X. (1842), p. 37. Jenner Fl. Tunb. Wells 178. 
 
 Spirogyra suhcequa, Kutz. Tab. Phy. v. t. 26, f. 2. 
 
 Rhynchonema rostratum, Kutz. Tab. Phy. v. t. 34, f. 3. (Not 
 Zygnema rostratum, Hass. Alg. t. 33, f. 1.) 
 
ZYGNEMACB^. 89 
 
 Zygnema neglectum, Hass. Alg. t. 23, f. 1 (not Petit). Hass. 
 Ann. Nat. Hist. x. 37. Jenner Fl. Tunb. Wells 178. 
 
 In ponds. Fruiting in August. 
 
 This species is rather a charaoteristio one, of which it appears to Us 
 that Zygnema neglectum, Hass., is only a form with three chlorophyll 
 bands. If the two species of Hassall are drawn to the same scale, it is 
 difficult to indicate any specific difference. The Rhyihchonema rostratum 
 of Kntzing is referred by Cleve to this species, but the Zygnema 
 rostratum of Hassall appears to be different, with thicker filaments and 
 much longer zygospores, and is rather referable to Spirogyra niUda. 
 The Spvrogyra negleeta of Petit cannot be the Zygnema neglectum of 
 Hassall. 
 
 This species is thus described by Hassall : — " Filaments about a foot 
 in length, with truncate extremities ; of considerable though rather less 
 diameter than those of S. nitida, mucous, glossy, and of a deep and 
 beautiful greeu colour ; investing membrane of the cells very evident 
 and transparent. Cells in the young filaments scarcely so long as broad, 
 but their length exceeds their breadth in those which have conjugated ; 
 round the interior of the cells five or six loose spiral tubes may be 
 faintly discerned ; these ooutaiu the reproductive globules (sic), which 
 are large and distinct, with a dark central nucleus. Sporangia oval 
 sometimes almost circular and flattened, lying in inflated cells, the 
 cavity of which they do not fill." 
 
 Plate XXXIV. fig. 2. a, sterile cells X 200; S, conjugating cells with 
 zygospores X 200 ; c, fertile cells of Bhynchonema form with zygospore 
 X 200 ; d, outline of zygospore X 400. 
 
 B. Chlorophyll bands single or double (rarely temate). 
 
 Spirogyza porticalis. Fauc7^. 
 
 Sterile cells with the extremities truncate, 2 to 4 times 
 longer than the diameter ; chlorophyll bands single, or binate, 
 rarely ternate. 
 
 Spores obtuse, ovoid, 1^ times longer than the diameter, 
 membrane even, chestnut colour. 
 
 Sporiferous cells equal to the length of the spore, or twice as 
 long, more or less turgid. 
 
 Size, Cells •032--05 mm. diam. Zygospore -08 X •048-'05 
 mm. 
 
 Cleve Monog. Zygn. p. 22, t. 5, f. 8 to 13. 
 
 Conjugata porticalis, Vauch. Conf. p. 66, t. 5, f. 1. 
 
 In ditches, &c. Fruiting in spring. 
 va/r. a. quinina. 
 
 Chlorophyll bands usually single. 
 
 Size. Cells ■035-'045 mm., about twice as long. 
 
 Zygnema quininum, Hass. Alg. t. 28, f. 1, 2. Harv. Man. p. 
 143. Landsborough Brit. Seaweeds p. 362. Eng. Fl. v. 362. 
 Eng. Bot. Ed. ii. p. 175. Harv. Man. 143. Johnst. PI. Berw. 
 ii. 256. Grev. Fl. Ed. 320. Mac, PI. Hib. 231. Fl. Devon 
 ii. 50. Hook. Fl. Scot. ii. 80. Dickie Bot. Guide, 296. 
 
90 ZYGOPHYCE^. 
 
 Spirogyra quinina, Kutz. Tab. v. t. 22, f. 2. 
 
 Spirogyra porticalis, Petit Spirogyra, p. 21, t. 5, f. 8-12. 
 
 Conferva spiralis, Dillw. Conf. t. 3. Eng. Bot. Ed. i. t. 16.56. 
 
 Zygnema spiralis, Eng. Bot. Ed. ii. t. 2561. 
 
 Conjugata quinina, Gray Arr. i. 297. 
 
 var. /3. decimina. 
 
 Chlorophyll bands usually 2, sometimes 3. 
 
 SizB. Cells •034-'04 mm., 2 to 4 times as long. 
 
 Zygnema deciminum, Hass. Alg. t. 23, f. 3, 4. Harv. Man. 
 p. 143. Johnst. Fl. Berw. ii. 255. Mack. Fl. Hib. 2, 31. Fl. 
 Devon ii. 50. Jenner Fl. Tanb. Wells 178. Grev. Fl. Edin. 
 320. Eng. Fl. v. 362. 
 
 Spirogyra decimina, Kutz. tab. v. t. 23, f. 3, 24, f. 1. Petit 
 Spirogyra p. 25, t. 8, f. 1-3. Eabh. Alg. iii. p. 242. 
 
 Spirogyra Jlavicans, Kutz. tab. v. t. 23, f. 3. 
 
 Spirogyra laxa, Kutz. Tab. v. t. 23, f. 3. 
 
 Spirogyra major, Kutz. Tab. v. t. 24, f. 2. 
 
 Conferva jugalis, Dillw. Conf. t. 5. 
 
 Confei-va injlata, Eng. Bot. Ed. i. t. 2376. 
 
 Zygnema inflatum, Eng. Bot. Ed. ii. t. 2510. Hook. Fl. 
 Scot. ii. 80. 
 
 Conjugata inflata. Gray Arr. i. 297. (?) 
 
 Conjugata decimina, Gray Arr. i. 299. 
 
 liar. c. liTuIaiis. Hass. 
 
 Size. Cells •032--036 mm., 5 to 10 times as long. 
 Zygnema rivulare, Hass. Alg. 144, t. 27, f. 1, 2. Annals 
 Nat. Hist. X. 38. 
 
 Spirogyra rivularis, Eabh. Alg. Eur. iii. 243. 
 
 TJndonbtedly if the Hterile threads of this species are carefnlly ex- 
 amined, they will furnish abnndant evidence that the number of spiral 
 bands is variable, for cells will constantly be fonnd in the same filament 
 in which either one or two bands ocoor. So that, with the great simi- 
 larity in f rnit, it wonld be folly to think of maintaining the two varieties 
 deeimirw, and quinina as distinct species, on account of the number of 
 chlorophyll bands. The Z. rivulare of Hassall, which we have included 
 as a third variety, is not uncommonly found in a sterile condition, in so 
 far as it can be determined in this stage, but hitherto we have not seen 
 it in fruit. It is said to be fonnd on the Continent in fructification, but 
 we have no knowledge of the Continental form. The spirals in the 
 sterile cells are usually three, and then very nearly identical with the 
 condition of the variety decimina, in which the bands are the same in 
 number, 
 
 Plate XXXV, fig. 1, iona quinina. o, sterile cells X 200; J, e, conju- 
 gating cells with zygospores X 200 ; d, outline zygospores X 400. Fig. 3, 
 form decimina, a, sterile cellr X 200 ; i, conjugating ceUs with zygo- 
 spores X 200 ; d, outline zygospore X 40O. Fig. 3, form rivularit, a, 
 Btei-ile cells X 200. 
 
ZYONEMAOE^. 91 
 
 C. Chlorophyll bands single. 
 Spixogyxa condensata. Vauch. 
 
 Sterile cells with the extremities truncate, and commonly 
 1 to 3^ longer than the diameter. Chlorophyll bands single, 
 rarely two, making 1^ to 2 turns of the spiral. 
 
 Spores broadly obtuse, ovoid, or subspherical, membrane even, 
 chestnut colour. 
 
 Sporiferous cells turgid, and usually shorter than the spores. 
 
 Size. Cells "04 mm. diam., zygospores 'OSS-'Oi mm. diam. 
 
 Cleve Mouog. Zygn. p. 21, t. v.f. 1-7. 
 
 Conjugata condensata, Vauch. Conf. t. 5, f. 2. Gray Arr. 
 i. 298. 
 
 Zygnema varians, Hass. Alg. t. 29, f. 3 and 4. Jenner 
 Fl. Tunb. Wells, 180. 
 
 Zygnema Woodsii, Hass. Alg. t. 33, f. 2. Jenner Fl. Tunb. 
 Wells, 180. 
 
 Spirogyra torulosa, Kutz. Tab. v. t. 20, f. 2. 
 
 Spirogyra nodosa, Kutz. Tab. v. t. 20, f. 3. 
 
 Spirogyra arcta, Kutz. Tab. v. t. 21, f. 2. 
 
 Spirogyra condensata, Kutz. Tab. v. t. 22, f. 3. Petit Spiro- 
 gyra, p. 22, t. 9, fig. 6-8. 
 
 JShynchonema Woodsii, Kutz. Tab. v. t. 34, f. 2 (not of Nord. 
 and Wittr. Exs., No. 789). 
 
 Spirogyra Flechsigii, Eabh. Hedw. i. p. 46. 
 
 Zygnema quininum, var. Hass. Ann. Nat. Hist. x. (1842) 35. 
 
 Spirogyra ulotrichoides, Kutz. Tab. v. t. 21,f. 3. 
 
 Spirogyra varians, Kutz. Sp. Alg. p. 439. Petit Spirogyra 
 p. 49, t. 4, f. 1-S. 
 
 Spirogyra infiata, Kutz. Tab. v. t. 21, f. 1-8. 
 
 In pools. Fruiting in spring. 
 
 From the number of synonyms quoted above, it may be inferred that 
 this is a variable species. All the forms seem to be incladed by Petit 
 under his Spi/rogyra condensata and 8. varians. 
 
 Hassall thus alludes to a peculiar nodoluae growth of some of the 
 forms : — " When a number of cells unite in regular order with those of a 
 neighbouring filament, no inJBlation of any of these oeourd ; but it fre- 
 quently happens that several adjoining cells of a filament for some reason 
 or other do not unite, although the remaining ones in that filament do, 
 in which case those which have not yoked themselves swell up, assuming 
 a monoliform appearance, and at the same time frequently emit blind and 
 irregular processes or prolongations, by which the cells manifest the 
 strong tendency which they have to conjoin themselves, but which some 
 cause, not evident, would appear to have frustrated. In some speci- 
 mens the number of inflated cells and blind processes is but small, 
 while in others the elongated cells are more numerous than those which 
 have united in the ordinary manner." A similar circumstance may 
 sometimes be observed in S. longata, especially in the short-celled 
 forms. 
 
92 ZYGOPHYCE^. 
 
 Plate XXX VI. fig. 1. a, sterile cells X 200 ; S, eonjngating cells with 
 zygospores X 200 ; c, sterile cells of inflated form X 200 ; d, conjugating 
 cells with zygospores X 200 j e, /, g, outlines of zygospores X 400. 
 
 Spixogyxa longata. Vauoh. 
 
 Sterile cells with the ends trnncate, 3 to 8 times as long as 
 broad, chlorophyll bands single or rarely two, making lA to 
 6 turns of a spiral. 
 
 Spores 1^ to 2 times as long as broad, membrane even, chest- 
 nut colour. 
 
 Sporiferons cells swollen and usually longer than the spore. 
 
 Size. Cells ■024--03 mm. diam. Zygospore •04--07 x -03 mm. 
 
 Cleve Monog. Zygn. p. 20, t. 3, f. 8-10; t. 4, f. 1-7 ; 1. 10, 
 f. 11-13. 
 
 Conjugata longata, Vauch. Conf. p. 71, t. 6, f. 1. 
 
 In pools and ditches. 
 
 var. u. commanis. 
 
 Sterile cells 3 to 8 times as long as broad. 
 
 Spirogyra longata, Kutz. Tab. v. t. 20, f. 1. Rabh. iii. 238. 
 Petit Spirogyra t. 5, f. 4, 5. 
 
 Zygnema commune, Hass. Alg. t. 28, f. 5, 6. Ann. Nat. Hist. 
 X. (1842) p. 39. Jenner Fl. Tunb. Wells, 180. 
 
 Zygnema astivum, Hass. Alg. t. 28, f. 3, 4. Ann. Nat. Hist, 
 xi. (1843), p. 433. Jenner Fl. Tunb. Wells, 180. 
 
 Zygnema angulare, Hass. Alg. t. 34, f. 1, 2. Jenner Fl. 
 Tunb. Wells, 180. 
 
 Zygnema angulatiim, Hass. Ann. Nat. Hist. x. (1842) p. 41. 
 
 Zygnema reversum, Hass. Alg. t. 33, f. 3. 
 
 Zygnema altematiim, Hass. Alg. p. 154. 
 
 Zygnema mirabile, Hass. Alg. t. 35, f. 1-3. 
 
 Spirogyra communis, Kutz. Tab. v. t. 19, f. 4. Petit Spiro- 
 gyra t. V. f. 1-3. 
 
 Ehynchonema angulare, Kutz. Tab. t. t. 34, f. 1. Rabh. iii. 
 232. 
 
 Jihynchonema reversum, Kutz. Rabh. iii. 232. 
 
 Spirogyra subtilis, Kutz. Tab. v. t. 19, f. 5. 
 
 Spirogyra mirabilis, Kutz Sp.p. 438. Petit Spirogyra p. 14, 
 t. 3, f. 3-4. 
 
 Conjugata longata, Gray Arr. i. 279 (?) 
 
 var. /3. tuxpis. 
 
 Sterile cells abbreviated. 
 
 Zygnema malformatum, Hass. Alg. t. 30, f. 1, 2. Ann. Nat. 
 Hist. X. (1842) p. 39. Jenner Fl. Tunb. Wells, 180. 
 
 Zygnema catceneforme, Hass. Alg. t. 30, f. 3, 4. Ann. Nat. 
 Hist. X. (1842), p. 39. 
 
 Zygnema abbreviatum, Hass. Alg. t. 34, f. 4. 
 
ZYGNEMACE^. 93 
 
 Spirogyra turpis, Kutz. Tab. v. t. 19, f. 2. Rab. iii. 238. 
 Spirogyra catceneformis, Kutz. Tab. v. t. 19, f. 1. Rab. iii. 
 238. Petit Spirogyra t. 3, f. 9-12. 
 
 Rhynchonema abhreviatum, Kutz. Rab. iii. 248. 
 
 We Tentnre to differ from onr friend Mens. Petit in uniting four of hia 
 species. In fact, if fovir species are to be accepted, we see no logical 
 grounds for refusing to accept a dozen, because of the excessive vari- 
 ability in the sterile cells. 
 
 Flate XXXVI. Jig, 2. a, i, sterile cells X 200; e, conjugating cells 
 with zygospores X 200 j d, fertile cells of Rhynchonema form with zygo- 
 spore X 200 ; e, fertile cells of mirabiUs form with zygospores X 200 ; 
 /, conjugating cells of catenmformis form with zygospores X 200 ; gi h, i, fc, 
 outline zygospores X 4:00. 
 
 Spirogyra flavescens. (HassJ Oleve. 
 
 Sterile cells with the ends truncate, 2 J to 5 times longer than 
 broad, chlorophyll bands single. 
 
 Spores attenuated, twice as long as broad, membrane even, 
 chestnut colour. 
 
 Sporiferous cells swollen, and usually longer than the spores. 
 
 Size. Cells -02 mm. diam. Zygospore -05 X '024: mm. 
 
 Cleve Monog. Zygn. p. 19, t, 3, f. 6, 7. 
 
 Boggy pools on heaths, &c. 
 
 form a. gracilis. 
 Zygospore about -03 mm. diam. 
 Zygnema gracile, Hass. Alg. t. 30, f. 5, 6. 
 Spirogyra gracilis, Kutz. Tab. y. t. 18, f. 5. Petit Spiro- 
 gyra p. 15, t. 3, f. 7, 8. 
 
 Zygnema malleolum, Hass. Alg. t. 34, f. 5. 
 Rhynchonema malleolus, Kutz. Tab. v. t. 33, f. 3. 
 
 form b. flavescens. 
 
 Zygospore about -02 mm. diam. 
 
 Zygnema flavescens, Hass. Alg. t. 30, f. 9, 10. Jenner Fl. 
 Tuiib. Wells, 180. 
 
 Spirogyra flavescens, Kutz. Tab. v. t. 18, f. 4. Petit Spiro- 
 gyra p. 15, t. 3, f. 5, 6. 
 
 Zygnema affine, Hass. Alg. t. 34, f. 6. 
 
 Spirogyra affinis, Petit Spirogyra, p. 18, t. 3, f. 12, 13. 
 
 Rhynchonema affine, Kutz. Tab. v. t. 33, f. 2. 
 
 /o?'m c. parva. 
 Zygospore about '01 mm. diam. 
 
 Zygnema parimm, Hass. Alg. t. 30, f, 7, 8. Ann. Nat. Hist. 
 X. (1842) p. 41. Jenner Fl. Tunb. Wells, 180. 
 Spirogyra parva, Kutz. Tab. v. t. 18, f. 3. 
 
 This species includes five of Hassall's species of Zygnema, which sub- 
 sequently were relegated by Kutzing, three to Spirogyra and two to 
 Rhynchonema. The Zygnema fla/vescens, parvum, and gracile, are sepa- 
 
94 
 
 ZYGOPHYCE^. 
 
 rated by distinotions so minute and variable, that they cannot be main, 
 tained as other than varieties, and Zygnema malleolum, and Z. afme were 
 at the time suspected of being varieties the one of the other. 
 
 Plate XXXVII. fig, 1. Variety gracilis, a, sterile cells X 200 ; I, 
 conjugating cells with zygospores X 200 ; a, fertile cells of Bhyncho- 
 nema form with zygospores X 200 ; d, outline zygospores X 400. Fig. 2, 
 variety flavescens. a, sterile cells X 200 ; b, c, conjugating cells with 
 zygospores X 200; d, fertile cells of Shynchonema form with zygospores 
 X 200 ; e, outline zygospores X 400. Fig. 3, variety pmrva. a, sterile 
 cells X 200 ; b, conjugating cells with zygospores X 200 ; e, outline 
 zygospores X *30. 
 
 Section 2. Cells replicate at the ends. 
 
 A. Chlorophyll lands usually two or more. 
 Spixogyza insignis. Hass. 
 
 Sterile cells with the extremities replicate, 4-J to 5 (rarely 6) 
 times as long as broad, chlorophyll bands 2 to 3, lax, with 1 to 2 
 turns of spiral, or nearly erect. 
 
 Spores ovate-elliptic, twice as long as broad, membrane even. 
 
 Sporiferous cells slightly swollen. 
 
 Size. Sterile cells -OS-'OSS mm. Zygospore •04:--05 mm., 
 2 to 3 times as long. 
 
 Eabh. Alg. Eur. iii. 243. 
 
 Zygnema insigne, Hass. Alg. 440, t. 103, f. 1,2. 
 
 Zygnema HassalUi, Hass. Alg. 157, t. 36, f. 4,5. Jenner Fl. 
 Ttmb. Wells, 182. 
 
 Spirogyra insignis, Kutz. Tab. v. t. 31, f. 4. Sur. Obs. 
 1. 1, f. a. 
 
 Bhynchonema HassalUi, Kutz. Tab. v. t. 32, f. 7. 
 
 Spirogyra Bravnii, Eabh. Alg. Ex. No. 1310, 1395. 
 
 Spirogyra Hantschii, Eabh. Alg. Ex. No. 1291. 
 
 Spirogyra Theobaldii, Kutz. Tab. v. t. 31, f. 2. 
 
 Spirogyra HassalUi, Petit Bull. Soc. Bot. Pr.; Spirogyra t. 2, 
 f. 6-8. 
 
 Rliynchonema gallicum, Eipart. in Petit Spirogyra. 
 
 In streams. 
 
 The number of British species in which the cells have replicate ends 
 is much less than of those with truncate ends. We have only included 
 two species with two or more chlorophyll bands, in one of which the 
 membrane of the zygospore is smooth, and in the other punctate. Doubt- 
 less neither of them are common. 
 
 Plate XXXVIII. jig. 1. a, d, sterile cells X 200 ; b, conjugating cells 
 with zygospores X 200 ; c, fertile cells of Shynchonema, form X 200 j 
 outline zygospore X 400. 
 
 Spixogyza calospoza. Cleve Mon. Zyg. j>. 26, t S,f. 1-5. 
 
 Sterile cells with the extremities replicate, 6 to 12 times as long 
 as broad, chlorophyll bands 1 to 3, making 2^ to 7 turns. 
 
 Spores elongate, obtuse ovoid, 11 to 2 times as long as broad, 
 membrane yellow, scrobiculate. 
 
 Sporiferous cells scarcely turgid. 
 
ZYGNEMACEJE. 95 
 
 form a major. 
 Diameter of threads '05 mm. Bands 2 to 3. 
 
 formji ininox. 
 Diameter of threads "032 mm. Band single. 
 Size. Zygospore -OTS-'Oge x -045 mm. 
 Archer in Quart. Journ Micr. Sci., 1873, xiii. p. 436. Petit 
 Spirogyra p. 11, t. 2, fig. 11-13. 
 
 Spirogyra protecta, Wood. F. W. Alg. t. 14, f. 3. 
 In bogs and moor pools. 
 
 Plate XXXVIII. fig. 2. a, sterile cells X 200 ; 6, c, conjugating cells 
 with zygospores X 200 ; d, outline zygospore X 400. 
 
 B. Chlorophyll bands single. 
 Spizogjrza quadzata. (Hass.) Petit. 
 
 Sterile cells 3 to 9 times aslong as broad. Fertile cells turgid, 
 quadrate. Zygospore elliptical. Sporoderm brown. 
 
 Size. Cells -024 to -027 mm. Zygospore •042--048 mm. 
 diam., IJ to 2 times as long. 
 
 Petit Spirogyra p. 8, t. 1, fig. 13. Bull. Soc. Bot. France 
 xxi. p. 14, t. 1, fig. 2. 
 
 Zygnema quadratum, Hass. Alg. 157, t. 37, f. 1, 2. Jenner 
 Fl. Tunb. Wells, 182. 
 
 Bhynehonema quadrata, Kutz. Tab. Phy. v. t. 32, f. 6. 
 
 In pools. 
 
 We have accepted Petit's diagnosis of this species, which Hassall had 
 seen only with the BhyncJwnana mode of conjugation, but which has 
 now been ascertained to conjugate in both ways. His description is very 
 short for a species which he says is " by no means uncomraon," and he 
 evidently depends as a specific feature on the quadrangular enlarge- 
 ments of the fertile cells. " Cells usually seven or eight times as long as 
 broad. Sporangia oval, large, and much elongated, contained within 
 quadrangular enlargements of the cells." 
 
 Plate XXXIX. Jig. 1. a, fertile cells in conjugation with zygospore 
 X 200, after Petit ; 6, zygospore in cell x 400. 
 
 Spirogyra Weberi. Kutz. 
 
 Sterile cells with the extremities replicate, 7 to 12 times as 
 long as the diameter, chlorophyll bands single, 3 to 8 turns of 
 the spiral. 
 
 Spores OToid, scarce broader than the sterile threads, mem- 
 brane even, chestnut, twice as long as broad. 
 
 Sporiferous cells scarcely turgid. 
 
 Size. Spores : (a) -072 x -034 mm. (/3) -068 x -034 mm. 
 
 Cleve Monog. Zygn. p. 25, t. vii., f. 1-10. 
 form a. inaequalis. 
 
 Diameter of thread -03 mm. Sporiferous cells scarcely 
 longer than the spores. 
 
 Zygnema incequale, Hass. Alg. 150, t. 32, f. 1 to 2. 
 
 Zygnema intermedivm, Hass. Alg. t. 37, f. 3. Ann. Nat. 
 Hist. X. (1842) p. 41. Jenner Fl. Tunb. Wells, 182. 
 
96 ZYGOPHYCE^. 
 
 Spirogyra inoeqiuilts, Kutz. Tab. v. t. 30, f. 3. 
 Zygnema Grevilleanum, Hass. Alg. 149, t. 31, f. 1, 2. Hass. 
 Ann. Nat. Hist. x. 38. Jenner Fl. Tunb. Wells, 180. 
 
 form b. subventxicosum. 
 
 Sporiferous cells 2 to 4 longer tban thespores. Diam. -026 mm. 
 Spirogyra Weberi, Rabh. Alg. Euv. iii. 233. 
 Zygnema sub-ventricosum, Hass. Alg. 150, t. 32, f. 4, 5. Jenner 
 Fl. Tunb. "Wells, 180. 
 
 Zygnema diductum, Hass. Alg. t. 37, f. 4. 
 
 Rhynchonema diductum, Kutz. Tab. v. t. 32, f. 3. 
 
 Spirogyra ventricosa, Kutz. Tab. v. t. 29, f. 5. 
 
 Zygnema ventricosum, Hass. Ann. Nat. Hist. x. (1842) p. 38. 
 
 Zygnema longatum, Hass. Alg. 151, t. 31, f. 3, 4. 
 
 In ditches. Fruiting in summer. 
 
 The absence of any measorements, or uniformity in magnification in 
 the fignres, renders it very difficult to determine many of Hassall's 
 species with any certainty. From present information we are nnable to 
 recognise Z. G^'emlleaimm as a distinct species. 
 
 Plate XXXIX. fig. 2. a, sterile cells X 200 ; S, c, conjugating cells 
 with zygospores X 200 ; d, fertile cells of ShyncTwnenia form with 
 zygospores X200. 
 
 Spizogyxa tennissima. Mass. 
 
 Sterile cells with the extremities replicate, 5 to 15 times as 
 long as the diameter. Chlorophyll bands single, making 3 to 6 
 turns of the spiral. 
 
 Spores broader than the sterile cells, elongated ovoid, twice 
 as long as the diameter, membrane even and chestnut colour. 
 
 Spoiiferous cells turgid. 
 
 Size. Spore -055 (a}r-058 (/3) x -024 ((2)--03 mm. (/?). 
 
 Cleve Monog. Zygn. p. 24, t. 6, f. 5-7. 
 
 form a, tennissima. 
 
 Sterile cells 8 to 16 times as long as broad. •012-'0l5 mm. 
 diam. 
 
 Sporiferous cells 2 to 3 times as long as the spores. 
 
 Zygnema tenuissimum, Hass. Alg. t. 32, f. 9, 10. Ann. Nat. 
 Hist. X. (1842) p. 41. Jenner Fl. Tonb. W., 180. 
 
 Zygnema minimuvi, Hass. Alg. t. 37, f. 8. 
 
 Spirogyra ienuissima, Kutz. Tab. v. t. 29, f. 2. Eabh. Alg. 
 Eur. iii. 233. 
 
 Rhynchonema minimum, Kutz. Tab. v. t. 33, f. 1. 
 
 Spirogyra Naegelii, Kutz. Tab. v. t. 29, f. 3. 
 
 form h. inflata. 
 Sterile cells 5 to 10 times as long as broad. •017-'02 mm. 
 diam. 
 
 Sporiferous cells scarcely longer than the spores. 
 
ZYGNEMAOB^. 97 
 
 Zijgnema varians, Hass. Ann. Nat. Hist. xi. (1843) p. 431. 
 
 Gonjugata inflata, Vaucli. Conf. p. 68, t. 5, f. 3. 
 
 Zygnema inflatum, Hass. Alg. t. 32, f. 6, 7. Jenner Fl. Tunb. 
 Wells, 180. 
 
 Zygnema Jenneri, Hass. Alg. t. 37, f. 6. Jenner Fl. Tunb. 
 Wells, 182. 
 
 Zygnema dubium, Hass. Alg. t. 37, f. 7. 
 
 Spirogyra gastroides, Kutz. Tab. v. t. 29, f. 4. 
 
 Rhynchonema Jenneri, Kutz. Tab. v. t. 32, f. 1. 
 
 Bhynchonema dubium, Kutz. Tab. v. t. 32, f. 2. 
 
 Spirogyra injlata, Rabh. Alg. Eur. iii. 233. 
 
 In pools. 
 
 This species includes the most delicate of British species with repli- 
 cate ends to the cells. In all the forms of both varieties there is an 
 evident tendency in the fertile cells to become more or less inflated. The 
 only difference which Hassall indicates between his Z. inflatum and Z. 
 tenwissimum is one of size, which may be influenced by the circum- 
 stances of growth. 
 
 Plate XXXIX. fl^. 3. a, sterile cells X 200 j J, conjugating cells of va- 
 riety a, with zygospores X 200 j 0, conjugating cells of variety i, with 
 zygospores X 200 ; d, outline of zygospores X 400. 
 
 Genus 46. SlROGONIum Kut%. (1843.) 
 
 Cells with parietal longitudinal chlorophyll bands. Fructi- 
 fying cells diverse, arising by unequal division of the thread- 
 cells, bending knee-like towards each other and growing 
 together, united at the point of adnation ; receiving-cells barrel- 
 shaped ; giving-cells short, cylindrical. Zygospore (elliptic) in 
 the receiving cell-wall. 
 
 The sterile cells, with parallel chlorophyll bands, resemble those of 
 Spirogyra, but differ in the genuflexuous conjugation. 
 
 Sizogonium sticticum. Xu-ta. 
 
 Sterile cells 2 to 5 times as long as broad. 
 
 Zygospore broadly elliptical, spore-coat double. 
 
 Sporiferous cells swollen, abbreviated. 
 
 Size. Cells '04 to -05 mm., 2 to 5 times as long. Zygospore 
 •042 X -075 mm. 
 
 De Bary Conj. p. 78, t. 2, figs. \-ff Rabh. Alg. Eur. iii., 256. 
 
 Sirogonium breviarticulatum, Kutz. Tab. Phy. v. t. 4. 
 
 Sirogonium Braunii, Kutz. Tab. Phy. v. t. 4. 
 
 Conferva stictica, Eng. Bot. t. 2463. 
 
 Zygnema curvatum, Ag. Eng. Fl. v. 362. Harv. Man. p. 
 143. Eng. Bot. Ed. ii. t. 2512, f. a. Hassall Alg. 143, t. 26, 
 f. 1, 2. 
 
 Choaspes serpentina, Gray Arr. 1, 299. 
 
 In ponds and ditches and moor pools. 
 
98 ZYGOPHYCE^. 
 
 " It forms large masses on the water, full of air-bubbles, being pale 
 and yellowish above, and of a blackish green beneath. Filaments not 
 Inbricous, nearly equalling those of Spirogyra nitida, bnt with much 
 longer arfciculationa. When young the colour is of a dull pale green, 
 and about three imperfectly spiral lines of shining grannies are with 
 difficulty distinguishable. Afterwards these lines become more con- 
 spicuous, the rest of the filament being now perfectly colourless, and 
 their component granules larger, but their arrangement is still irregular. 
 The filaments subsequently unite here and there, not by every articula- 
 tion, and their connecting processes are usually nearer to one end of the 
 vessicle than to the other. Such filaments are divaricated at the points 
 of connection. In some of the combined articulations the contents 
 appear unchanged, in others they form a mass of larger granules than 
 in the lines, and some have a large oval sporidium which often swells 
 the joint. Some traces of unchanged lines occur, now and then, in the 
 fructifying vessicles." — English Botany, 2nd ed., p. 176. 
 
 Plate XL, Jig. 1. a, sterile cells X 200 ; b, c, d, e, conjugating cells 
 X 200 ; /, zygospore X 400. After De Bary. 
 
 Genus 47. ZTGOGONIUM. Kvtz. (1843.) 
 Cells cylindrical or barrel-shaped, with a compact, often many- 
 layered glittering cell-wall. On each side near the middle an 
 irregular chlorophyll- body, each furnished with a starch granule, 
 both often confluent in an axile string (in the very thick-walled 
 cells usually concealed by granules). Connection of the copu- 
 lating threads ladder-like. The protuberances of the two con- 
 tiguous inter-growing threads that receive the chlorophyll- 
 contents are bounded by partitions into fructifying-cells, which 
 then coalesce into a not-contracted zygospore. 
 
 Zygogonium ericetoram. De Bary Qmj. p. 79. 
 
 Sterile cells, If to 2 times as long as broad. 
 
 Zygospores subglobose or oblong, sporoderm rather thick, 
 even. 
 
 Size. — Cells -013 to -018 mm. diam. Zygospore -013 x '025 
 mm. 
 
 var. u. terzestiis. 
 
 Zygogonium ericetorum, Kutz. Tab. v. t. 10, Dickie Bot. Guide, ^ 
 296. Jenner Fl. Tunb. Wells, 184. Hass. Alg. 174, t. 41, 
 f. 1, 2. 
 
 Zygogonium torulosum, Kutz. Tab. v. t. 14. 
 
 Conferoa ericetorum, Eng. Fl. v. 350 ; Harv. Man. 125 ; 
 DiUw. Conf. 1. 1, Eng. Bot. 1st Ed., t. 1553, 2nd ed. t. 2473. 
 Grev. Fl. Ed. 318. Grev, Crypt. Fl. t. 261 (?) Mack. Hib. 
 224. Fl. Devon, ii. 51. Hook. Fl. Scot. ii. 81. 
 
 Conferva alpina, Eng. Fl. v. 350. Harv. Man. 125. Grev. 
 Sc. Crypt. Fl. t. 261, f. 2. 
 
 On heaths. 
 
zygnemacejj:. 99 
 
 var. h, Aquaticum. 
 
 Zygogonium didymum, Eabh, Hedw. 1, t. 3, f. 2. 
 Zygogonium Agardhii, Eabh. Alg. Eur. iii., p. 253. 
 Conferva purpurascens, Carm. Eog. Fl. v. 350. Harv. Man, 
 123. Mack. Hib. 224. 
 
 In pools, bogs, &c. 
 
 This is a veiy polymorphous species, some of the forms being terres- 
 trial, and always sterile, others are aqnatio producing zygospores. The 
 old name of Zhjgogonium erictorum has been retained, but undoubtedly 
 all these Tarious forms belong to Zygogonium Agardhii, Kabh. (^Zyg- 
 didymum, E.) 
 
 " The colour, no less than the condition of the endoohrome, varies 
 considerably in this species. In some specimens the filaments are of a 
 bright green, in which case they have always been found immersed in 
 water ; while in others, and more frequently, they are purple, of which 
 colour they invariably are when found spreading over swampy heaths." 
 
 PlaUXL.fig. 2. Terrestrial form, a, sterile cells X 100 Mg.Z. 
 var. aguatioum. a, sterile cells X 400; b, e, conjugating cells with 
 zygospores X 400. 
 
 Doubtful Species. 
 Zygogonium gzacile. Berk. 
 Sterile cells about five times as long as broad, of a pale or 
 yellowish green colour. 
 Zygospore unknown. 
 Size. Cells ■014.--016 mm. diam. 
 Rabh. Alg. Eur. iii., 255. 
 Zygnema gracile, Berk. Glean, t. 12, f. 3, 
 
 Pace of a dripping rock. 
 
 Eabenhorst includes this with uncertain species of Zygogomium, but it 
 seems more probable that it is a Zygnema, and perhaps one of the 
 varieties of Z. ToMcherii. The following is the original description : — 
 
 " Pale dirty yellowish green, mucous ; threads extremely fine, articula- 
 tions not at all constant in length, 4 to 8 times as long as broad, marked 
 in the centre with two approximate roundish globules. Slender fila- 
 ments occur in the same mass, with joints longer in proportion, the 
 green mass not divided into two distinct portions. I have not seen it 
 conjugated." — Berkeley. 
 
 Plate XL. fig. 4. Sterile cells X 400. 
 
 Genus 48. KOUGEOTIA. Be Bary. (1858.) 
 
 Cells with axile chlorophyll-plates. Copulation ladder-like. 
 Zygospore drawn together in the swollen, bladdery, persisting 
 middle space. 
 
 De Bary includes this genus in Zygnemeoe, although Wittrook joins it 
 with J]£esocarpus, and it seems to us very difficult to indicate any true 
 generic distinction apart from the dividing off from the parent cells of 
 the empty persistent cells which remain some time attached to the zygo- 
 
 P 
 
100 ZYGOPHTCE^. 
 
 spore ; nevertheleaa we have not followed Wittrock in uniting jHfou- 
 ffeotia, Mesocarpus, Pleurospermum, Craterospermum, and Statiros- 
 permum under the one genus, Mouffeotia,, because we think that there 
 are sufBcient characters to warrant the retention of Staurospermum 
 apart from Mesocarpus. If the mode of development in the following 
 two species is accurately appreciated, this genus is more allied to Zygo- 
 goniv/m than Mesocarpus. See Archer in Quart. Micro. Joum., 1866, 
 p. 271. 
 
 nCongeotia glyptospenna. DeBary Conj. p. 78, t. S,f. 20-25. 
 
 Sterile cells 7 to 12 times as long as broad. 
 
 Zygospores large, oval, with a thick, firm, yellow-brown 
 epispore. 
 
 Sporiferous cells elongated. 
 
 Size. Cells -Ol-'OIS mm. 6 to 10 times as long. Zygo- 
 spore -Oiex-OSS mm. 
 
 Eabh. Alg. Eur. iii. 255. Archer in Quart. Journ. Micr. 
 Sci. 1866, p. 65. 
 
 As pointed out by Mr. Archer (loc. cit.) " this plant is not truly a 
 Mesocarpus, but in its mode of conjugation more nearly approaches 
 certain &/gnemata. It is no doubt related, on the one hand to Meso- 
 carpus (Hass.) ; like it the endoohrome forms a compressed longitudinal 
 band, and like it too, the zygospore is formed half-way between the two 
 conjugating joints. But, it is distinguished strongly by the fact that 
 here the whole cell contents ' primordial utricles ' and all, of the two 
 conjugating joints completely coalesce, leaving the old cell-walls empty, 
 in order to form the zygospore ; whilst in Mesocarpus the contact of the 
 primordial utricles of the two conjugating cells is not followed by a 
 complete coalescence of the two into the zygospore ; but by a concen- 
 tration of the principal part of the green and solid contents in the con- 
 necting canal half-way between the two joints, and the shutting ofE 
 thereupon of the residue of the pale granular contents remaining in each 
 parent joint, the denser central portion becoming the spore, and that 
 cut off on each side eventually becoming effete and lost. Hence in 
 Mougeotia glyptosperma the spore is the actual result of the complete 
 fusion of the entire cell contents of the two conjugating joints— it is 
 the true zygospore ; whilst in Mesocarpus the ultimate spore is a 
 daughter-cell, as it were, of the zygospore. Therefore, on the other 
 hand, the present plant shows an affinity to Zygnema ; but it is, of 
 course, completely distinct in the flattened band of endochrome, not 
 doubly stellate, as in that genus, not to speak of the extremely different 
 comparative length of the cells, which, within the limits of each, is 
 constant." 
 
 Plate XLI. fig. 1. a, sterile cells X400; b, c, conjugatiag cells with 
 zygospores, after De Bary , X 200 ; d, zygospore, after De Bary, X 400. 
 
 Mougeotia laevis. Archer Micr. Journ. 1867 t. 8, /. 1-3. 
 Sterile cells twice as long as broad. 
 
 Zygospores broadly elliptic or oval. Epispore thick, brown. 
 Sporiferous cells sometimes elongated. 
 
 Size. Cells ■02--25 mm. Zygospore about -04:5 X -036 mm. 
 Eabh. Alg. Eur. iii. 255. Archer Micr. Journ. 1866, p. 270. 
 Zygogonivm Iceve, Kutz. Tab. v. 1. 13. 
 
 In ditches and pools. 
 
ZYGNEMACEjE. 101 
 
 Mr. Archer has thus described the present plant ; — " Cells short, vary- 
 ing from nearly quadrate to three or four times longer than broad, 
 according to the interval of time elapsed since division ; the contents 
 bright herbaceous green, forming an axile compressed band (never sepa- 
 rate stellate chlorophyll bodies as in Zygnema) ; the conjugation taking 
 place by short wide processes, which, along with the shortness of the cells 
 or joints, gives the pair of oonj ugating filaments somewhat the appearance 
 of a perforated ribbon-like structure ; the total cell contents of each 
 pair of conjugating joints became massed together into an elliptic zygo- 
 spore within the inflated transverse tube ; the longer diameter of the 
 zygospore placed vertically to the length of the filaments ; the cavity 
 occupied thereby not shut off by any septum from the cavities of the 
 parent joints. It was evident that there was no septum separating the 
 zygospore from the cavities of the parent cells, but it lay freely in the 
 inflated transverse process, though frequently in contact with its walls 
 about the middle." 
 
 Flate XL2. fig. 2. a, sterile cells X 400 ; b, fertile cells with zygo- 
 spores X 200. 
 
 8uh-Family 2. MESOCABPBiE. 
 
 Cells cylindrical, united in threads, with axile plates of 
 chlorophyll. Zygospore the shape of the mother-cells ; not 
 contracted, separating by three to fire partitions into a central 
 firm-walled resting spore, and two or four lateral decaying 
 cells. 
 
 The method of conjugation and spore-formation in the Mesocwrpa was 
 not thoroughly understood until it was investigated and explained by 
 De Bary (" Conjugaten," 1858), who first recommended the separation 
 of the Mesoca/rpece from the Zygnemeos, and their recognition as separate 
 families. His exposition of the conjugation of the Mesocarpeos is thus 
 summarised by Wittrock* in a memoir submitted to the Swedish Academy : 
 — " Two cells grow together in the common manner by conjugation out- 
 growths, and a resorption of the double septum between the two conjuga- 
 ting cells takes place. By this a cruciated or H-shaped double cell is 
 formed, in which at first no other change takes place than that the canal 
 of conjugation is somewhat widened, and that the chlorophyll-coloured 
 part of the contents of the double cell moves into the canal of conjuga- 
 tion, and into the parts of the double^ cell nearest to the canal. This 
 cruciated or H-shaped cell, thus formed immediately by the conjugation, 
 De Bary regards as the zygospore of the Mesocarpece, and gives it the 
 character of being ' not contracted ' in contrast with the zygospore of 
 Zygnemece and Desmidiew. This zygospore exists, however, only for a 
 very short time as such. The above-named moving of the chlorophylla- 
 ceous bodies (not of the whole protoplasmic mass) into the connecting 
 canal having been accomplished, the zygospore is divided by two or four 
 septa into three or five cells, of which one, the central one, is a hypno- 
 spore, rich in chlorophyllaceous protoplasm (and later in oil), whilst the 
 two or four lateral cells, containing no chlorophyllaceous protoplasm, are 
 sterile, and soon going to die. Thus the MesocarpecB have, according to 
 De Bary, spores of two kinds, namely (1), zygospores, which are formed 
 
 * "Ou the Spore-formation of the Mesocarpese." By V. B. Wittrock. Stockholm. 
 1878. 
 
102 ZTGOPHTCEa:. 
 
 simply by the growing together of the two conjugating cells, without 
 contraction, and which do not rest, and (2) hypnospores (resting spores), 
 which are formed by the partition of the zygospores, and which rest (as 
 the name indicates) for a time before germinating. The Zygnem&ji and 
 SesmidieiB have, on the contrary, according to De Bary, spores of only 
 one kind, namely, typical zygospores, in the formation of which a fusion 
 and contraction of tie whole protoplasmic contents of the conjugated 
 cells takes place, and which become hypnospores without a preceding 
 partition."' 
 
 Wittrook adds: — "To me it seems perfectly clear that De Bary is 
 quite right in saying that the hypnospores of the Mesocarpets are not 
 analogous to the zygospores of the ZygnemeiB, or in other words, that 
 they are not zygospores at all. The hypnospores of the Mesoca/rpecB are 
 formed by partition, and not by an immediate fusion of the protoplasm 
 of conjugating cells, as the case ought to be with zygospores." 
 
 He tiien proceeds to refer to Pringsheim's observations on this subject 
 with commendation (•' Jahrbucher " xi., 1877). " The act of conjuga- 
 tion may be divided into two different stages. The first, being properly 
 speaking only introductory, consists in the two cells which participate in 
 the conjugation growing together by conjugation outgrowths, and the 
 septum between the cells thus growing together being resorbed. This 
 pMrt of the act of conjugation is what Pringsheim calls copulation. The 
 second stage consists iu an intimate fusion taking place of the proto- 
 plasmatic contents of the conjugating cells. This fusion is effected here 
 in the Mesoca/rpeoe principally through the moving of the chlorophyll 
 colonied parts of the protoplasm (the chlorophyllaceous bodies) into and 
 to the neighbourhood of the somewhat widened conjugation canal. This 
 second and more important stage of the fecundation Pringsheim calls 
 conniibium. The conjugation having taken place in this manner, its 
 effect appears by the tripartition or quinquepartition of the cruciated or 
 H-shaped cell formed by the copulation. Of the cells formed by this 
 partition, the central one is fertile, the two or four lateral ones sterile. 
 The result of the conjugation is consequently not one cell, but several 
 cells, and not cells of one kind, but of two, namely, one propagative cell 
 (a spore), and around it two or four cells not capable of germination. It 
 would be difficult to find a reasonable interpretation of such a result, save 
 the one suggested by Pringsheim, of its being a sporocarpium, and to me 
 this interpretation seems not only reasonable, but perfectly natural, for 
 although the sporocarpium does here remain on a very low, not to say 
 the very lowest, stage of development, it does, however, already possess 
 the constituent parts of a typical sporocarpium. It has a nucleus and 
 a pericarpinm, or at least an equivalent to one. The nucleus is the 
 single central spore-cell, and the jpericarpium is represented by the two 
 or four lateral sterile cells." 
 
 " If the explanation given above is accepted, the essential difference 
 betreen these Algae and their nearest relations, ZfygnemefB and DesmU 
 diecBj might be expressed in the following manner : — ^The result of the 
 connnbium iu the former is a sporocarpium (and their spore is conse- 
 quently a carpotpore), but the result in the latter is a zygospore." 
 
 Wittrook then proceeds to show that in one species the formation of 
 the spores can take place equally in the manner of Mesocarpits, Plagio- 
 spermum, and Staurospermum, equally by tripartition, quadripartition, 
 and quinquepartition, and hence he concludes that those genera are not 
 sound, and that all three should be included under sub-sections of the 
 same genus. We have not followed this suggestion, but have retained 
 Mesocarpus and Staurospermum as distinct, relying upon the difference 
 of form in the central cell. 
 
 For further details we refer the student to the Memoir from whence 
 the foregoing observations are abstracted. 
 
ZYQNEMAOBiE. 108 
 
 Genus 49. KESOCARFUS. Hass. (1845.) 
 Spore sphserical or oval, between two cylindrical, straight or 
 slightly in-bent lateral cells. (a) Copulation ladder-like, 
 threads free, or with one end attached ; (b) copulation lateral 
 between two neighbouring cells of a thread, rarely ladder-like. 
 Sterile cells often with a knee-like bend, and intergrown at the 
 bend with similar cells of another thread. 
 
 Inolading also the genera Pleurocarjpus and Craleros^permv/m of Brann. 
 
 t Spore membrane Borobioulate or punctate. 
 
 M. nnmmuloides, Sass. 
 
 M. depressus, Rass. 
 t+ Spore membrane smooth. 
 
 M. parvalas, Hass. 
 
 M. recurvus, Hass. 
 
 M. scalaris, Hass. 
 
 Sub-gen. Pleuroca/rpus, Braun. 
 
 M. pleurocarpus, De Ba/ry. 
 
 t Spore membraiie serohieulate or pwnciate, 
 niesocazpus nummuloides . (Hass.) Ds Bam/. 
 
 Sterile cells 7-14 times as long as broad. Zygospore spheri- 
 cal, or broadly ovoid ; membrane brown, scrobiculate. 
 
 Size. Cells '015 mm. diam. Zygospore '044 X -034 mm. 
 
 De Bary Conj p. 80, t. 8, f. 9, 10. Cleve Mon. Zyg. p. 
 30, t. 9, f. 4, 5. Hass. Alg. 169, t. 45, f. 1. Eabh. Alg. 
 Eur. iii. 257. 
 
 Sphmrocarpus nummuloides, Hass. Ann. Nat. Hist. xii. 187, 
 t. 7, f. 12. 
 
 In ditches. Fruiting in September. 
 
 Mate XLI. Jig. 3. a, sterile cells X 400 ; b, fertile cells, with zygo- 
 spores, X 400. 
 
 Kesocaipus depzessus. Hass. 
 
 Sterile cells 7-12 times as long as broad. Zygospore ellipti- 
 cal, compressed ; membrane brown, punctate. 
 
 Size. •007--015 mm. 
 
 Hass. Alg. 168, t. 44, f. 1. Jenner Fl. Tunb. Wells 184. 
 
 Sphmrocarpus depressus, Hass. Ann. Nat. Hist. xii. 186, t. 
 7, f. 11. 
 
 var. B. ovalis. Mabh. Alg. Eur. iii. 257. 
 
 Mesocarpus ovalis, Hass. Alg. 169, t. 44, f. 2. 
 SplicBrocarpus ovalis, Hass. Ann. Nat. Hist. xii. 189, t. 7, f. 
 15. 
 In boggy waters. 
 
104 
 
 ZYGOPHYCKiE. 
 
 There aeems to be no specific difference between the two species of 
 <S. depressus and S. avails of Hasaall, the only feature relied upon being 
 that the filaments in the latter are scarcely more than half the diameter 
 of the former. 
 
 Plate XLI. Jig. 4. a, sterile cells X 400 ; b, fertile cells, with 
 zygospores, X 400. ]<ig. 5, var. avails, a, sterile cells X 400 j b, fertile 
 cells, with zygospores, X 400. 
 
 tt Spore membrane smooth. 
 Mesocaxpus paivulns. {3ass^ De Bary. 
 
 Sterile cells 5-12 times as long as broad. Zygospore spheri- 
 cal ; membrane even, commonly twice the diameter of the 
 threads. 
 
 Size. Cells -Ol mm. Zygospore •02-024 mm. 
 
 De Bary Conj. p. 80, t. 2, f. 15. Cleve Mon. Zyg. p. 31, t. 
 9, f. 6,7. Hass. Alg. 169, t. 45, f. 2, 3. Jenner Fl. Tunb. 
 Wells 184. 
 
 Sphoerocarpus parvulus, Hass, Ann. Nat. Hist. xi. 434, t. 7, 
 f. 13, 14. 
 
 Mougeotia splendens, Kutz. Tab. Phy. v. p. 1. 
 
 var B. angustus. Sass. 
 
 Mesocarpus parvulus, var. teniiissina, De Bary Conj. t. 11, f. 
 10-14. 
 
 Mesocarpus angustus, Hass. Alg. 170, t. 45, f. 4. 
 
 Sphosrocarpus angustus, Hass. Ann. Nat. Hist. xii. 187, t. 7, 
 f. 16. 
 
 Mixed with other Algse, in ponds, &c. 
 
 Plate XLII. fig. 3. a, sterile cells X 400 j J, c, fertile cells, with zygo- 
 spores, X 400. Mg. 4, var. angusttis. u, sterile cells X 400 ; b, fertile 
 cells, with zygospores, X 400 ; c, mature zygospore X 400. 
 
 Mesocaxpus scalazis. {Bass.) De Bary. 
 
 Sterile cells 2-4 times as long as broad ; zygospore spheri- 
 cal or broadly ovoid ; membrane brown, even, about equal in 
 diameter to the threads. 
 
 Size. Cells '034 mm. diam. Zygospore -034 mm. diam. 
 
 De Bary Conj. p. 80. Cleve Mon. Zyg. p. 32, t. 9, f. 
 11, 12. Hass. Alg. 166, t. 42, f. 1. Hass. Ann. Nat. Hist. x. 
 p. 45 ; xii. t. 7, f. 7. Rabh. Alg. Eur. iii. 257. Kutz. Tab. 
 Phy. V. t. 5. 
 
 Mesocatpus intricatus, Hass. Alg. 1 67, t. 43, f. 1. Jenner 
 Fl. Tunb. Wells 184. 
 
 Sphoerocarpus intricatus, Hass. Ann. Nat. Hist, xii, 186, t. 
 7, f. 9. 
 
 In boggy pools, &c. 
 
ZYGNEMACEiE. 105 
 
 We can recognize no plausible grounds on which the M. intricatus of 
 HaBsall can be maintained as a species distinct -from 3f. scalaris. 
 
 flats XLII. fig. 1. a, sterile cells X 400; J, conjugating cells, with 
 zygospores x 400. 
 
 Mesocazpus zecuzvus. Sass. 
 
 Sterile cells 5 to 10 times as long as broad. 
 Zygospore globose. Sporoderm brown, even. 
 Size. •012-'018 mm. Zygospore -023 mm. diam. 
 
 Hass. Alg. 168, t. 44, f. 1. Eabh. Alg. Eur. iii. 257. 
 Sphcericarpus recurims, Hass. Ann. N. Hist. xii. 186, t. 7,f. 10. 
 
 In ditches. 
 
 Plate XLII. fig. 2. o, sterile cells X 400; 6, conjugating cells with 
 zygospores X 400. 
 
 Sub-Genus Plbueocahpus. Braun. 
 
 ntesocazpus pleuzocazpus. Be Ba/ry Conj.p. 81. 
 
 Sterile cells 2 to 3 times as long as broad. 
 
 Zygospores subglobose, brown, even. 
 
 Size. Cells •025--03 mm. Zygospore -03 mm. diam. 
 
 Pleurocarpus mirabilis, Braun. Alg. Uni. p. 60. Eabh. Alg. 
 iii, 258. 
 
 Zygogonium pleurospermum, Kutz Tab. v. t 13. 
 
 Mougeotia genuflexa, Ag. and others. Eng. Fl. v. 360. Eng. 
 Bot. Ed. 11. t. 2505. Jenner. PI. Tunb. Wells, 182. Hass. 
 Alg. 172, t. 40, f. 2. Harv. Man. 141. Mack. PI. Hib. 231. 
 Dickie Bot. Guide, 296. 
 
 Conferva .genuflexa, Dillw. Conf. t. 6. Eng. Bot. Ed. 1, t. 
 1914. 
 
 Zygnema genuflexum, Johnst. Fl. Berw. ii. 257. Grev. PI. 
 Ed. 320. 
 
 Serpentaria genuflexa, Gray Arr. 1, 300. 
 
 var, compzessus. 
 
 Mougeotia eompressa, Eng. Fl. v. p. 360. Eng. Bot. Ed. 2, 
 p. 172. Harv. Man. 141. 
 
 Zygnema compressum, Lyngb. Hyd. Dan. t. 58. 
 Serpentaria eompressa, Gray Arr. 1. 300. 
 Pleurocarpus compressus, Babh. Alg. Eur. iii. 258. 
 
 In moor pools, &c. 
 
 This widely diffused species forms vast yellowish-green masses, which 
 Harvey says are often thirty feet in diameter ; we have often met with 
 thern covering several square feet. The filaments are fragile, soon 
 breaking into short lengths, bent almost at right angles and united at the 
 angles, hence the old name of Mwvkgeotia genuflexa. 
 
 Plate XLIII. fig. I. Cells in conjugation X 400; t, fertile cells 
 with zygospore, after De Bary X 400 ; c, u, zygospores X 400. 
 
106 ZYGOPHYCE^. 
 
 Genvs 50. STAVROSPERUKVBI. Kutz. (1843.) 
 
 Spores four cornered, between the truncated corners of four 
 sessile lateral cells (cells of all the species up to twenty times 
 longer than broad.") 
 
 t Sporoderm porose. 
 
 S. quadratum, Hass, 
 +t Sporoderm verruoose. 
 
 S. graoillimum, Hass. 
 ttt Sporoderm smooth. 
 
 S. oapnoinum, Kuta. 
 S. viride, Kviz. 
 
 t Sporoderm porose. 
 Stauzospermum quadzatum. {Bass.) De Bary. 
 
 Sterile cells 10 to 20 times longer than broad. 
 
 Epispore quadrangular, with the angles truncate, not repli- 
 cate, sides straight, covered with large-pores (about 50 on the 
 longer side). 
 
 Size. Cells •015-'02 mm. Zygospore •04-*044 mm. 
 
 De Bary Conj. p. 81, t. 8, f. 11. Cleve Mon. Zyg. p. 34, t, 
 10, f. 3. Rabh. Alg. Eur. iii. 259. 
 
 Staurocarpus quadrangulatus, Hass. Ann. Nat. Hist. xi. p. 
 434. Jenner. Fl. Tunb. Wells, 184. 
 
 Staurocarpus quadratus, Hass. Alg. 178, t. 48, f. 1. 
 
 Mougeotia quadrangulatus, Hass. Ann. Nat. Hist. xii. 185, 
 t. 7, f. 3. 
 
 In ponds, ditches, &c. 
 
 Plate XLIJI. fig. 2. a, sterile cells X 400 ; 6, h, conjugating cells 
 with zygospores X 400. 
 
 tt Sporoderm verruoose. 
 Stauzospezmum gxacillimum, (JIass.) 
 
 Sterile cells 8 to 15 times as long as broad, pale yellowish 
 green. 
 
 Zygospore quadrate, the sides deeply sinuate, angles retuse. 
 Sporoderm ven-ucose. 
 
 Size. Cells -006 -008 mm. Zygospore -02 mm. diam. 
 
 De Bary Conj. p. 81. Eabh. Alg. Eur. iii. 260. 
 Staurocarpus gracillirrms, Hass. Alg. 179, t, 49, f. 2. Jenner 
 Fl. Tunb. Wells, 184. Hass. Ann. Nat. Hist. xii. 185, t. 7, f. 6. 
 
 In bogs and moor pools. 
 
 Tlate XLIIl.fig. 3. it, sterile cells X 400 ; 6, conjtigating cells with 
 zygospores X 400. 
 
ZYGNEMACBJi:. 107 
 
 ttt Sporodei'm smooth. 
 Stauzospezmum capucinum. Kutz. 
 Sterile cells 6 to 14 times as long as broad. 
 Zygospore quadrate, angles obtuse or truncate, sides often 
 deeply sinuate. Sporoderm even. 
 
 Size. -015 X02 mm. Zygospore '03 X -04 mm. 
 
 De Bary Conj. p. 81. Rabh. Alg. Eur. iii. 259. 
 
 Staurocarpus ghttinosus, Hass. Alg, 177, t. 47, f. 1.- 
 
 Staurocarpus ecerulescens, Hass. Alg. t. 47, f. 2. Jenner PI. 
 Tunb. Wells, 184. 
 
 Mougeotia glutinosa, Hass. Ann. Nat Hist. xxii. t. 7, f. 1. 
 
 Staurocarpus capucinus, Hass. Ann. Nat. Hist. xii. p. 184, 
 t. 7, f. 2. 
 
 Mougeotia ecerulescens, Eng. PI. v. 360. Haw. Man. 141. 
 Eng. Bot. Ed. 2, t. 2506. 
 
 Conferva ecerulescens, Eng. Bot. t. 2457. 
 
 Agardhia ecerulescens, Gray Arr. i. 299. 
 
 Leda eapueino, Bory in Mong. & Nest. Ex. 793. 
 
 In ditches and ponds. 
 
 The filaments soon acquire a bluish tinge, and in drying assume a 
 purple hue. 
 
 Plate XLIV. Jig. 1. a, sterile cells X 400; 6, conjugating cells with 
 zygospores X 400. 
 
 Stauzospezmum vizide. Kuiz. 
 Sterile cells 10 to 20 times as long as broad. 
 Epispore quadrangular, angles truncate and replicate, sides 
 concave, smooth. 
 
 Size. Cells -008 mm. Zygospore -025 mm. 
 
 De Bary Conj. p. 81, t. 2, f. 17-18. Clave Mon. Zyg. p. 34, 
 t. 10, f. 4-5. Rabh. Alg. Eur. iii. 260. 
 
 Staurocarpus gracilis, Hass. Ann. Nat. Hist. xii. 185, t. 7, 
 f. 5. Hass. Alg. 179, t. 49, f. 1. Jenner PL Tunb. Wells, 184. 
 
 Staurocarpus vireseens, Hass. Alg. 178, t. 48, f. 2. 
 
 Staurocarpus affinis, Hass. Ann. Nat. Hist. xii. 185, t. 7, f. 4. 
 
 Staurospermum franconicum, Reinsch. Algen. PI. p. 217. 
 
 In ditches. 
 
 Plate XLIV. fig. 2. a, sterile cells X 400; 6, ooningatiug cells 
 with zygospores X 400 ; c, development of zygospores from conjugated 
 cells X 400, after De Bary, 
 
 Sub-Family 3. Gonatonemeji. 
 
 Cells cylindrical, much elongated, united in threads, -with 
 axile plates of chlorophyll. Agamospores produced without 
 conjugation in cells continuous with, and partitioned from the 
 
 mother cells. 
 
 Q 
 
108 ZYGOPHYCE^. 
 
 Wittrock inclndes his single genus 6o)iatonema in the Mesocarpeee as 
 au agamosporous form, 'without ascertained conjugation. A.s an excase 
 for this he says : — "If we attached importance only to the neutral or 
 Eezaal natmre of the spore formation, as some of the modern systema- 
 tizing botanists do even in the lower Cryptogams, we should be obliged 
 to form a separate family for it, which might not even be placed in the 
 class of Conjvgatce. To me the accordance with Mesocarpea as to 
 the vegetative cells and the formation of the spores seems too great to 
 aUow the separation of Gonatonema from this family. It may not be 
 unnecessary here to call to mind that the class of B'mtomacem in which 
 the formation of spores is in general effected through conjugation, does 
 also embrace some genera where the spores are formed neutrally." 
 
 At the risk of condemnation as a " modem systematizing botanist," we 
 do not feel content to include this genus in the MesocarpeiB, and have 
 therefore relegated it to a separate family until more complete evidence 
 is furnished as to whether it really should be associated with the Conju- 
 gate at all, although its affinities seem to lie in that direction. All we 
 are justified by the facts to assume is that it is an aberrant form, which, 
 on the faith of its vegetative character may for the present be retained 
 in proximity to the Mesocarpers until its relationship is better established. 
 
 Gends 51. GONATONEMA. Wittrock. (1878.) 
 Spores (agamospores not carpospores) without conjugation, 
 formed by biseptation of the mother cells, which latter are bent 
 angularly, and alternately, at the point of fructification. 
 
 Wittrock illustrates this genus by means of a species not yet ascer- 
 tained to be British, but which he regards as congeneric with Hassall's 
 species hereafter described. "Its vegetative stage consists of cylindrio 
 cells arranged in a single row. The membrane of the cells is very thin, 
 and consists of pure cellulose. The bottoms of somewhat older cells 
 are gently curved inwards, which gives rise to a small lens-shaped room 
 between the cells. The contents of the cells consist of (1) a parietal 
 thin colourless layer of protoplasm ; (2) an axile chobophyll-ooloured 
 rather thick band of protoplasm (the single chlorophyllaceous body of 
 the cell) which runs through the whole length of the cell, and which is 
 most frequently more or less excavated at both ends of the cell ; in the 
 band of chlorophyll occur the so-called ' starch granules,' in a number 
 of 2 to 4 ; (3) a rounded nucleus, which has its place at the side of the 
 chlorophyllaceous body, or very often in a small circular opening in the 
 middle part of the band of chlorophyll ; (4) small drops of oil, attached 
 partly to the inner side of the parietal layer of protoplasm, and partly 
 to the outer side of the chlorophyllaceous band ; and (5) colourless cell 
 liquid, which fills the vacuoles between the parietal layer of protoplasm 
 and the axile chlorophyllaceous band. 
 
 " In purely vegetative cells the chlorophyllaceous body is found to pos- 
 sess the power of making free, and rather quick movements. This species 
 thus gives a second instance of independent movements of chlorophyl- 
 laceous bodies belonging to vegetative cells. 
 
 "The formation of vegetative cells takes place by biportition, exactly 
 in the same manner as in the Mesocarpete. The cells destined to bring 
 forth spores have always a very considerable development as to length. 
 While the vegetative cells just formed by bipartition are only 5 to 6 
 times as long as thick, the cells which are ready to form spores are at 
 least 9, and more often 12 to 16 times as long as thick. A rather con- 
 siderable increase as to volume, by development in length, does conse- 
 quently take place in these cells before they are capable of fulfilling 
 their propagative purpose. 
 
ZYGNEMAOEiE. lt)9 
 
 " The first sign of a beginning spore-formation is that the cell widens 
 at its middle, so that this part resembles a cask. This widening is not, 
 however, equally powerful on all sides, but is stronger on one side than 
 on the other sides. At the same time the cell bends at its middle like a 
 knee, so that its two halves form a more or less obtuse angle with each 
 other. The point of the angle is placed where the before-mentioned 
 more powerful widening of the cell has taken place. Almost always the 
 formation of spores takes place at the same time in all the cells of a 
 filament. Then it regularly occurs that the cells bend alternately in 
 •opposite directions, so that if cell No. 1 bends to the right, cell No. 2 
 bends to the left. No. 3 to the right, and No. 4 to the left again, and so 
 on. Consequently the cells in a filament-producing spores will form a 
 zig-zag line. Exceptions from this rule do, however, now and then 
 occur I thus, that two cells abutting on each other bend in the same 
 direction, after which the two next bend in an opposite direction and so 
 on. When this occurs, the filament is gently curved like an S, alter- 
 nately in two directions. When the spore-forming cell widens and 
 bends, the chlorophyllaceous band of the cell is often interrupted at its 
 middle part, by which the cell gets two chlorophyllaceous bodies instead 
 •of one. The chlorophyll-coloured protoplasm now begins anew to give 
 proofs of its power of free motion. The chlorophyllaceous body (or 
 bodies if there are two) moves freely and rather quickly, from the other 
 parts of the cell to the widened middle part. When all of it has entered 
 this part of the cell, which has thus become almost quite filled with 
 •chlorophyll-coloured protoplasm, the cell is divided into three cells by 
 two septa, appearing one on each side of the chlorophyll filled central 
 part. The cells formed by this partition are of two essentially different 
 kinds. The two lateral cells have very little living contents. All the 
 chlorophyll-coloured protoplasm is gone, and only the thin parietal layer 
 of protoplasm and some drops of oil are left. The rest of the contents 
 are only colourless cell-liquid. These cells have in fact filled their pur- 
 pose. They soon die, and remain, as mere skeletons of cells, attached 
 for some time (two or three weeks) to the central cell. The central cell is, 
 in contrast to the lateral cells, very rich in living contents, having re- 
 ceived all of the chlorophyll-coloured protoplasm of the mother-cell. It 
 is also designed to become the hypnospore, through which the propaga- 
 tion of the species is to be affected. But before it becomes a complete 
 hypnospore it is to pass through several stages of development. The 
 first, of these is that the cell-contents surround themselves with a new 
 layer of cellulose (mesosporium) within the original one (exosporinm). 
 The mesosporium increases by-and-bye in thickness till it is considerably 
 thicker than both the exosporium and the endosporium (which appears 
 later). The mesosporium gets no sculpture (as is the case with so many 
 Mesoca/rpece) it remains always smooth. But having been at the begin- 
 ning hyaline, it soon assumes a faint yellow colour. Within the meso- 
 sporium a new layer of cellulose forms during the first week ; this is 
 called endosporium. It remains always hyaline and very thin. During 
 this time the contents of the cell have also suffered a change. The 
 chlorophyll-coloured protoplasm, at least the greater part of it, has 
 changed into a fat oil, which is coloured in the same manner as the 
 mesosporium, i.e., a faint yellow. The hypnospore which is now 
 ready, shows a somewhat different shape, if regarded from different 
 sides. If regarded in the position it has when the curvatures of the 
 spore-forming filament are directed to the right and left of the ob- 
 server, the spore is, as a rule, non-symmetrically elliptic, with abrupt 
 ends, very seldom it is almost circular. The want of symmetry con. 
 sists in the spore being more convex on the side towards which the knee 
 of the mother-cell has bent. If we imagine the spore being turned a 
 quarter of a turn round its longitudinal axis, it appears somewhat 
 
110 zyoophycej:. 
 
 narrower, and perfectly elliptical, with abrupt ends. How the spores 
 behave when germinating I have not yet had any opportunity of observ- 
 ing." 
 
 " Thus it appears from the foregoing details that the spores are always 
 formed without a preceding act of conjugation. The spore formation, 
 therefore, may be regarded as neutral, or we may assume that as in 
 exceptional cases spores may be formed by the instrumentality of a 
 single cell, in this ease the exception has become the rule, and the spores 
 would then be regarded as parthenospores, and not as agamospores." 
 
 Under these circnmstances of development, Wittrock considers him- 
 self justified in proposing the genus Gonatotienia for the two forms, the 
 one Gonafoiiema ventricosiun, on which the above observations were 
 made, and the other the species which Hassall described as Mesocarpus 
 tiotatUia. 
 
 Gonatonema notabile. (Hdss.) (Vittr. 
 
 Sterile cells 8 to 10 times as long as broad, sometimes longer. 
 
 Zygospore, front view cylindrical, side view bent so as to be 
 convex on one side, concave on the other, truncate at the ends, 
 same diameter as the vegetative cells. 
 
 Size. Cells •012--015 mm. 
 
 Wittrock Mesocarpete, p. 16, fig. 14. 
 Mosocarpus notabilis, Hass. Alg. 170, t. 46, f. 2. 
 Mougeotia notabilis, Hass. Ann. Nat. Hist. x. p. 46. 
 Staurosperimim notabile, Eabh. Alg. Ear. iii. 261. 
 
 Found in great abundance in some brick fields near Notting 
 Hill. — Hassall. 
 
 Here follows the original description by Hassall : — " Filaments at first 
 cylindrical, but subsequently becoming angalated, the angle of flexion 
 being situate in the centre of each cell. Cells usually about 8 or 10 
 times as long as broad, but frequently longer. Sporangia non-symme- 
 trical, a single one being placed in the angle formed in each of the cells.'^ 
 
 We have nothing to add to this description, never having seen the 
 plant in question, and are able only to reproduce Hassall's figures. 
 
 Plate XLl V. fig. 3. a, sterile cells ; i, fertile cells, after Hassall. 
 
BOTRYDIACE^. Ill 
 
 Order III. SIPHOPHYGE^. 
 
 Unicellular alg», usually at the time of fruiting bicellular. 
 Cells utricle-shaped, often prominently branched ; branches with 
 terminal vegetation, at length shut off by a septum, some trans- 
 formed into oosporangia, others into antheridia. Cell contents 
 green, mucilaginous, granulosa, filled with chlorophyllose vesicles 
 and starch granules. 
 
 Propagation by free cell formation, or zoogonidia, or 
 oospores. 
 
 Plants aq[uatic or terrestrial, some marine. 
 
 Family I. Botrydiace^. — Propagation by free cell for- 
 mation and by zoospores. 
 
 Family II. Vauchbriacb^. — Propagation by oospores 
 and zoogonidia. 
 
 Family L BOTRYDIAOE^. 
 
 Plants small, terrestrial, unicellular. Cell in the beginning 
 globose, afterwards clavate or pyriform, and inflated ; vertex 
 rounded, a long time closed, attenuated downwards ; base 
 divided into delicate hyaline radicles, filled within with a 
 mucilaginous green granulose cytioplasm, with age collapsing 
 at the apex, and finally wasting away. Cell contents modified 
 into an indefinite number of resting spores ; spore contents, in 
 germinating, becoming modified into a number of sexual zoo- 
 spores conjugating and forming isospores. 
 
 Gends 52. BOTRITDIUni. Wallr. 
 
 Vegetative plants unicellular, increasing by cell division and 
 zoospore formation ; asexual uniciliate zoospores ; sexual bici- 
 liate isospores, sometimes globular, and alike capable of 
 germination, sometimes compressed and hexagonal, famished 
 with a few tuberculate thickenings. 
 
 See for information Braun's " Eejuvenesoence," pp. 128, 193, 220, 
 274 ; Parfitt in " Grevillea," Vol. i., p. 103 ; Archer in " Grevillea," Vol. 
 i., p. 105 ; Eostafinski and Woronin, " Ueber Botrydinm granulatum," 
 1877; Lawson in "Trans. Bot. Soc, Edinburgh," vi., 424 ; Archer in 
 " Quarterly Journal of Mioroecopical Science," 1878, pp. 446-452. 
 
 B 
 
112 SIPHOPHYCE^. 
 
 The following is a summary of Bostafinski and Woronin's researches 
 on this genus : — 
 
 If a plant be placed in water, its contents become modified at the 
 latter part of the day or at night into zoospores. Ultimately the wall 
 swells, then bnrsts somewhere at the top, and the zoospores resulting 
 from the division of the parietal stratum escape. If the plant be only 
 moistened, the zoospores do not swarm ont, but come to rest within the 
 collapsed wall. Snch were known to previous observers as "germ 
 cells " or " gonidia." 
 
 The zoospores are elongate-oviform, 5-8 X 20 mm., with a single 
 flageUum, and 2 to 4 chlorophyll granules. Having swarmed out, they 
 soon come to rest, lose the flagellum, become surrounded by a mem- 
 brane, increase in size, and germinate on damp earth, in which stage 
 they represent the so-called Protoeoctnis iotryoides. 
 
 The large ordinary zoosporangia are also otherwise modified. If one 
 is allowed to dry, its membrane collapses, loses colour, and soon becomes 
 empty. The protoplasmic contents pass down to the ramifications of 
 the root. Here they break up into numerous cells, sometimes two or 
 three side by side, but chiefly in a continuous chain ; each cell furnished 
 Vfith a separate membrane. 
 
 These are capable of three forms of development: — (1) If removed 
 from the soil and placed in water, the cell becomes a subterranean 
 zoosporangium. The formation of the zoospores is independent of light 
 at any hour of the day or night. The zoospores are similar to those 
 above described, and germinate in the same manner. (2) If a chain of 
 these root cells be laid on moist earth, each protrudes a hyaline process, 
 which enters the soil, the opposite end being elevated, and thus each 
 root cell becomes a vegetative plant. (3) If the root cells are not 
 removed, and kept equably moist, they also germinate in the earth, 
 become inflated, put forth a root process, the wall of which becomes 
 very much thickened on the inner side below the inflated upper portion. 
 By interoulary growth of the root portion the upper part becomes raised 
 aloft, so that the apex is carried above the surface of the soil. These 
 products of modifled root cells are named hypnos'poTanges, and are equi- 
 valent to so-called Botrydium Wallrothii. When dried, the hypno- 
 sporanges retain their power of germination during the whole year, and 
 when placed in water form zoospores at any hour of the day and night, 
 germinating and forming young plants as above. 
 
 The uniflagellate zoospores germinate on a moist substratum. On 
 earth or sand they thrive badly, but better on clayey or muddy soil. In 
 water they never germinate, but come to rest, axe surrounded by a 
 double membrane, and lie dormant for months. If these be transferred 
 upon a clayey soil, they commence to form a, vegetative plant. If the 
 zoospores be sparingly distributed over the soil, and the whole kept 
 equally moist, the vegetative plants become ordinary zoosporanges. The 
 plants are sometimes modified into hypnosporanges. 
 
 Thus, vegetative plants can be increased by cell division directly 
 from zoospores, become ordinary zoosporanges, with such consequences 
 as root cells, &c., or they may be directly modified into hypno- 
 sporanges. But there is yet another way in which existence may be 
 carried on. If exposed to drought, the following phenomena occur :^ 
 The wall collapses more or less, and the protoplasmic contents break up 
 into a number of cells, each surrounded by a deUeate membrane, its 
 contents homogeneous, at first green, then passing into red. These are 
 the spores, and have been known by such names as Protococeus coccoma, 
 P. palustris and P. hotryoides. These spores become changed in water 
 to zoosporangia, their contents giving rise to zoospores in the manner 
 already described. If the spores be still green, their zoospores will 
 have a distinct fusiform figure, with two cilia at one end. They consist 
 
BOTRTDIAOE-E. 113 
 
 of slightly coloured protoplasm. These zoospores oonjugate iu twos, 
 sometimes several together. They come in contact by their ciliated 
 ends, then come to touch laterally by the unooloured portions, when 
 the fusion of the conjugating zoospores takes place, immediately after 
 which they present a cordate figure, and in the middle a colourless 
 vacuole. Finally, the isospore thus originating becomes globular, the 
 vacuole occupying the centre. 
 
 If the zoospores be isolated before conjugation, they will in the end 
 break up, without presenting any products capable of germination. 
 
 The zoospores originating from red spores have a different figure, 
 their posterior end being rounded, but they have otherwise the same 
 structure, and behave in the same manner as the others. The red 
 spores maintain their germinative power for years, but after two years 
 their zoospores are languid, and offer a parthenogenesis of a peculiar 
 kind. The red spores, if kept moist only, become nothing altered after 
 weeks, whilst the green, under these circumstances, may directly 
 germinate into vegetative plants. 
 
 The isospores are at first globular, and capable of immediate germina- 
 tion. They also present resting stages, the original form becoming 
 modified. Soon after conjugation these are flattened, with irregular 
 lateral boundaries, which become on the following day hexagonal. The 
 membrane becomes thickened, and presents tnberculations at the 
 margin, but no secondary membrane is formed. Brought upon damp 
 earth, they soon become globular, and otherwise behave as ordinary 
 isospores. 
 
 'hi order to distinguish that which appertains to the cycle of alterna- 
 tion of generations from the rest, the simple method is to start from the 
 fertilized germ, and see what are the modifications which are essential 
 in order to arrive again at the same reproductive process. In this case 
 we have the isospore — it germinates — produce the vegetative plant, 
 which needs neither to divide, nor produce a sexual zoospore, nor to 
 become an ordinary zoosporange — it can directly produce spores. These 
 close the first generation. The second oospore generation occurs in the 
 germination of these spores in the form of sexual zoospores, which 
 directly lead to the formation of the isospore — the limits of two genera, 
 tions. AH the rest are but phenomena of adaptation. 
 
 " Thus, in nature, the vegetative plants in spring almost all become 
 zoosporangia, and spread the growth over considerable areas. Zoospores 
 which fall into the water are not lost ; they acquire a double membrane, 
 and lie dormant until they chance mechanically to arrive on moist soil. 
 If drought sets in, the plasma retreats to the roots ; if the earth be 
 some time a little moist, the root cells become hypnospores, awaiting 
 the rain in order to develop multitudes of zoospores ; but if the earth 
 becomes rapidly dried, the root cells remain unaltered, until a moistening 
 excites the formation of zoospores. A great many of the root cells can 
 manifestly accidentally reach the surface of the soil, and thus, according 
 to the state of the moisture of the earth or of the air, sometimes ger. 
 minate, sometimes become zoospores." All this in the spring. The hotter 
 months favour the formation of spores, but at that time only the 
 vegetative plants are mostly to be found, either undergoing cell division 
 or spore formation. They can also furnish uniciliate zoospores without 
 becoming modified into ordinary zoosporanges. 
 
 Formation of ordinary zoospores may be accomplished in a fourfold 
 way — 
 
 1. From the vegetative plant. 
 
 2. From the ordinary zoosporange. 
 
 3. From the root cell. 
 
 4. From the hypnosporange. 
 
114 SIPHOPHYCE^. 
 
 Farther modes of increase are — 
 
 5. Cell division. 
 
 6. Formation of spores. 
 
 7. Formation of zoospores. 
 
 This plant possesses also fivefold resting stages — 
 
 1. Of the asexual zoospores laid in water — for months. 
 
 2. Of the root cells — the year thronghont in which they 
 
 originated. 
 
 3. Of the hypnosporanges — ^ihe year thronghont in which they 
 
 originated. 
 
 4. Of the spores — for years. 
 
 5. Of the isospores — at least over the year in which they 
 
 originated. 
 
 Plate LXV., Botrydium granulatum. Fig. 1, plants of the natural 
 size. Fig. 2, zoosporanginm X 30. Fig. 3, the same, five hom^ after- 
 wards, with the zoospores escaping at the apex, X 30. Fig. 4, zoospores 
 X 520. Fig. 5, differentiation of the plasma in the root, and the forma- 
 tion of root cells, X 30. Fig. 6, root cells in water producing zoospores 
 X 160. Fig. 7, the resulting zoospores X 520. Fig. 8, the same, 24 honrs 
 after swarming, X 520. Fig. 9, the same, fonr days later, X 520. Fig. 
 10, the same, eight days later, x 520. Fig. 11, copulating swarmspores 
 X 520. Fig. 12, zoospores derived from a spore, after sis and a half 
 hours, X 160. Fig. 13, sexual swarmspores in conjugation X 520. Fig. 
 14, isospores, 24 hours old, X 520. Fig. 15, stellate isospores, more than 
 a day old, X 520. Fig. 16, young plant resulting from vegetation of 
 isospore. All after Bostafinski and Woronin. 
 
 Botrydium granalatam. lAnn. 
 
 Usually gregarious, often aggregated, rarely conflaent ; cells 
 globose, pyriform, size of a poppy seed, or mustard seed, or 
 larger, leek-green, apparently pulverulent. 
 
 Botrydium granulokum, Jenn. Fl. Tunb. Wells 176. Parfitt 
 in Grevillea i., p. 10. Eng. Fl. v., p. 321. Harv. Man. 150. 
 Kirsch. Alg. Schl, p. 84. Trans. Bot. Soc. Edin. vi., 424. Eng. 
 Bot. ii., p. 127, t. 2422. Hass. Alg. t. 77, f. 5. 
 
 Hydrogastrwn granulatum, Eabh. Alg. Eur. iii., 265. Des7. 
 Fl. Ang. 19. 
 
 Lichenoides fungifoi-me, Ray Syn. iii., p. 70. 
 
 Tremella palustris, Dillen. Hist. Muse. 55, t. x., f. 17. 
 
 Botrydium argillaceum, Grey. Alg. Brit., p. 197, t. 19. Kutz. 
 Tab. vi., t. 54. 
 
 Vaucheria granulata, Grev. Fl. Ed. 306. Gray. Arr. i., 290. 
 
 Vaucheria radicata, Hoot. Fl. Scot, ii., 93. 
 
 Vaucheria multieapsularis, Harv. Man. 149. Gray Arr. i., 
 252 (?). 
 
 Ulva granulata, Lightf. Fl. Scot. 976. Hull. Brit. Fl. 309. 
 
 Tremella granulata, Hads. Fl. Ang. 566. With. Arr. iy., 
 80. Eng. Bot. i., t. 324. 
 
 On tbe ground in swampy places. 
 
 "The plant about IJ mm. diam. ; the upper portion, or that above 
 ground, globular, gradually narrowing downwards, and passing into one 
 
VAUCHEEIACBiB. 115 
 
 or two principal roots, which become gradually ramified into many fine 
 rootlets ; the chlorophyll contents at the beginning dense and homo- 
 geneous, and clothing the inner cell membrane, eztend only to the neck 
 of the root ; the membrane is rather rigid. Upon being broken the cell 
 contents become extruded, the membrane collapses as a thick pellicle, 
 whose contents admit of being completely pressed out. The fluid 
 contents in this condition consist of finely granular plasma, tinged by 
 chlorophyll granules. Subsequently the green plasma layer becomes 
 separated from the membrane, breaks up into single equal-sized portions, 
 which become rounded off, coated with a membrane, and gradually 
 individualized as daughter-oella. At last the entire globose cell is 
 densely filled with rounded daughter-cells ; whilst, previoua to this state, 
 the plant presented an intensely grass-green colour, it shows in this 
 latter state a clear or sea-green colour. Mature and immature plants 
 hence readily admit of being distinguished by the tint with the unassisted 
 eye. The membrane of the mother individual at last passes to decay ; 
 it collapses, and the daughter -cells become the germs of new indivi- 
 duals in the soil. The maturity of the individuals occurs towards 
 autumn, and accordingly the germ cells lie resting in the earth during 
 winter, and germinate in the following spring. The development of the 
 germ cells to new individuals takes place without formation of a 
 ' prothallus ' (' ohue Vorkeimbildung '). One end elongating as a root, 
 at once penetrates the earth ; the other end becomes developed as the 
 above-ground portion. The diameter of a ripe germ cell is 0'009-0'012 
 mm. The plants prefer to establish themselves on the surfaces of the 
 large clefts which are produced when the waters retreat and the ground 
 becomes gradually dried by the air." — Reimch. Algen Flora, p. 218. 
 
 See also " GreviHea " Vol. iv., p. 105, since which period the Memoir by 
 Bostafinski and Woronin has appeared, and that has pretty well estab- 
 lished the complex character of reproduction in this little plant. 
 
 Family II. VAUOHBRIACB^. 
 
 Algffi mon^cious (rarely di»oious), ceespitose, unicellular or 
 bicellular. Thallus with terminal vegetation, utricle-shaped, 
 elongated, more or less branched. 
 
 Propagation either sexual, by oospores fecundated by sper- 
 matozoids, or non-sexual by zoospores. 
 
 Sporangium terminal, formed by the globosely clavate swelling 
 of the tip of the thallus, cut off by a septum, contents dark 
 green, at length enclosing one large zoospore, densely clad with 
 vibratile cilia. 
 
 Oogonium lateral, sessile, or borne on a more or less elongated 
 simple, or partite, pedicel ; cytioplasm at length converted into 
 a large oospore. 
 
 Antheridium lateral, sessile, or cut off by a septum from the 
 upper portion of a lateral branch, in which numerous spermato- 
 zoids are generated, which at length become free. Spermatozoids 
 oblong, furnished with two unequal cilia (except in one 
 species). 
 
116 SIPHOPHYCEiB. 
 
 Consult Thuret in "Annalesdes Sciences Naturelles, Botanique," 1843. 
 Walz in Pringsheim's " Jahrbucher " for 1866. Braun " Eejuveuesoence," 
 pp. 128, 140, and following. 
 
 Genus 53. VAUCHERIA. D. C. (1805.) 
 
 Characters the same as giyen above for the Family. 
 
 Two or three arrangements of the European species of Vaucheria have 
 heen proposed, difEering slightly in detail. The following is that of Pro- 
 fessor Nordstedt; — 
 
 VATJCHERIA. 
 
 A. Antheridia not separated from the thallus by a short empty 
 boundary cell. 
 
 a TUBULiGEBvE. Antheridia little or scarcely bent, oblong 
 cylindrical, or lanceolate, with an opening at the top. Eed 
 pigment bodies not collected in the middle of the mature 
 oospore. Oogonia and antheridia almost stemless. 
 
 * Oogonia nearly round. 
 
 1 V. dichatoma (L) Diaecious. 
 
 2 V. ThwetiiWoT. MoniEcious. 
 ** Oogonia not round, more or less oval, 
 
 frequently rather oblique. 
 
 3. V. aversa, Hass, 
 
 4. V. sericea, Lyngb. 
 
 b COENlcuLATvB. Antheridia bent in the form of a horn, or a 
 hook, placed on the short and bent side branches of the 
 thallus. Brown pigment in the middle of the mature 
 oospores. 
 
 aa Sessiles. Oogonia sessile (or with exceeding short 
 stems) beside the antheridia on the thallus. 
 
 5. V. SilVmynm, Ag. 
 
 6. V. sesnlis (Vauch). 
 
 bb Macemosce. Antheridia at the end of a fruit branch, 
 which, somewhat lower down, carries the 
 oogonium. 
 
 # Oogonia turned upwards. 
 
 ■f Antheridia and oogonia bending in op- 
 posed planes, forming an angle with 
 one another. When the oospores 
 fall they are surrounded by the 
 oogonium membrane, which is not 
 changed to slime. 
 
 7. V. gemifiata, Walz. 
 
 8. V. hamata, Walz. 
 
 ft Antheridia and oogonia (mostly) 
 bending in parallel planes, the 
 oogonium membrane turns to slime 
 and dissolves. 
 
 9. V. terrestris, Lyngb. 
 ** Oogonia turned-downwards. 
 
 10, V. unoinata, Kutz. 
 
 c Antheridia straight, with the top covered, and a pair of fruiting 
 tubes standing out at the side. 
 
 11. V. De Ba/ryana, Woron. 
 
VAUCHEEIACEJi:. 117 
 
 B. Between the antheridia and thallus itself is found a shorter empty 
 boundary cell (not containing chlorophyll). 
 
 a AndbophoBjE, Several horn-shaped bent antheridia placed 
 on a swollen cell containing chlorophyll, which is fixed to 
 the side of the thallus, by means of the boundary cell. 
 12. V. aynandra, Woron. 
 b PiLOBOLOlDEiB. Antheridia bordering immediately on the 
 boundary cell (frequently provided with several mouths). 
 aa Oogonium borders immediately on the thallus branch. 
 * Several fructification tubes on the 
 oogonium. 
 
 13. T. coronata, Nordst. 
 
 ** Oogonium with only one fructification 
 opening, but the antheridia with 
 several. 
 + Oospore round. 
 
 14. v. intermedia, Nordst. 
 
 15. V. sphcerospora, Kordst. 
 t t Oospore lens-shaped. 
 
 16. V. pilutoloideg, Thur. 
 ib Below the oogonium a boundary cell. 
 
 17. V. litorea, Hofm. 
 Place uncertain. 
 
 18. V. tuberosa, Br. 
 
 19. r. trifwrcata, Kutz. 
 
 The sexual reproduction in Taucheria has been minutely described by 
 Pringsheim, of which we give an abstract. Taucheria, besides the 
 asexual multiplication by zoospores also exhibits a true sexual propaga- 
 tion, effected by means of the two organs known as the "hornlets" and 
 the spores, the latter being more correctly termed " sporangium." Both 
 organs arise like papillary branches from the tube, and in close proximity. 
 It is usually the case that the papilla destined to become the hornlet is 
 formed sooner than that in which the sporangium originates. The two 
 papillae even from the first differ so widely in dimensions, that they can 
 .scarcely be confounded. The papilla which becomes the hornlet soon 
 elongates into a short cylindrical slender branch, which at first rises 
 perpendicularly from the tube, then curves downwards until it comes in 
 contact with the tube, often forming a second, or a third curve, and in 
 this way always represents a more or less stunted branch, which fre- 
 quently exhibits several spiral turns. The papilla of the neighbouring 
 sporangium usually begins to appear at the time when the hornlet is 
 commencing its first turn ; but the period at which it arises is very 
 indeterminate, for it sometimes appears much earlier, whilst the hornlet 
 is still perfectly straight, sometimes much later after it has curved, so as 
 to form two limbs of equal length. 
 
 The papilla destined to become the sporangium gradually enlarges 
 into a considerable-sized lateral out-growth of the tube, far exceeding the 
 hornlet in width, whilst in length it is barely equal to the straight limb 
 of the latter. This out-growth which is afterwards symmetrical, 
 ultimately throws out a beak-like prolongation on the side looking 
 towards the hornlet, the rostrum of the sporangium, whence the latter 
 acquires its peculiar form, resembling that of a half lieveloped vegetable 
 ovule. Tip to this period the hornlet as well as the sporangium are not 
 shut off from the tube by any septum ; the cavity of the hornlet and that 
 of the sporangium consequently remain uninterruptedly continuous with 
 the parent tube, and are filled with similar contents. A number of 
 chlorophyll granules in an albuminous plasma and rounded oil globules, 
 constitute a dense lining to the tube, the sporangium, and the hornlet. 
 Between this and the cellulose membrane is the thin colourless cutaneous 
 layer. 
 
118 SIPHOPHYCE^. 
 
 At this stage a septum is suddenly formed at the base of the 
 sporangium, which is henceforth an independent cell, completely 
 separated from the parent tube. Even before this septation there may 
 be noticed in the rostrate elongation directed towards the homlet, the 
 gradual accumulation of a colourless fine granular substance, of the same 
 nature as that with which the wall of the parent tube, and the 
 sporangium is lined on the inner surface, which has already been termed 
 the "cutaneous layer." This accumulation in the fore part of the 
 rostrum is continued after the formation of the septum between the 
 sporangium and the tube, and in consequence of its continued increase, 
 the remaining contents of the sporangium are by degrees pushed back 
 towards the base. Whilst these phenomena are being manifested in the 
 sporangium, the hornlet also undergoes remarkable changes. In its 
 apex, tihe contents, owing to the disappearance of the chlorophyll, have 
 become almost colourless, more or less. Thus the point of the homlet, 
 like that of the sporangium, appears at this time to be filled with a 
 colourless substance, which is not constituted by an accumulation of the 
 cutaneous layer, but manifestly arises from a molecular change 
 associated with an alteration of form and colour in the contents pre- 
 viously existing at the' apex. So soon as the contents at the point of the 
 homlet have thus become colourless, they appear to be constituted of a 
 very fine-grained granulose mucous substance. As soon as the trans- 
 formation of the contents has taken place, the colourless apex of the 
 hornlet is suddenly separated from the lower green portion by a septum, 
 and is thus transformed into an independent cell, without communication 
 with the parent tube. The point at which the septum is formed is not 
 very determinate, the portion out off being sometimes larger, sometimes 
 smaller. 
 
 After the formation of the septum in the hornlet the colourless mucous 
 in its apex gradually assumes a more determinate form, and at 
 this time a large number of minute, perfectly colourless, rod-like 
 bodies may be readily perceived crowded together irregularly, and 
 as it were imbedded in the surrounding mucous. Close observation 
 will disclose an indistinct movement exhibited even thus early 
 by some of the little rods, from which their destination may be 
 anticipated. 
 
 This perfecting of the hornlet coincides with that stage of development 
 of the sporangium at which the accumulation of the cutaneous layer in 
 the anterior part of the rostrum has attained its greatest extent, and 
 these conditions immediately precede the act of impregnation , which is 
 effected in the following manner : — 
 
 The pressure within the sporangium, especially in the direction of the 
 rostrum, becomes greater and greater in consequence of the continued 
 increase of the cutaneous layer in the fore part, until ultimately the 
 membrane is ruptured exactly at the point of the rostrum, and allows a 
 portion of the cutaneous layer to escape. The extruded portion 
 becomes detached, and assume.s the character of a drop of mucous, which 
 remains lying near the openirg of the sporangium, and ultimately 
 perishes. The accumulation of the cutaneous layer in the fore part of 
 the rostrum, and the escape of a portion of it, are merely the mechanism 
 by which the opening is produced in the sporangium destined for the 
 admission of the sperm atozoids. Immediately after the formation of 
 this opening in the sporangium, and in remarkable coincidence with 
 the escape of the cutaneous layer through the ro.'trura, the homlet opens 
 at the apex, and pours out its contents. Innumerable excessively minute 
 rod-like corpuscles ( 005 mm.), mostly isolated, escape at once through 
 the orifice. Those already isolated exhibit an extraordinarily rapid 
 movement in all directions, and those still imbedded in the mucous do not 
 become detached until afterwards, when they follow the others with, 
 equal rapidity. The field of view is soon covered with mobile corpuscles. 
 
VAUCHBRIACE2E. Il9 
 
 In great number (20, 30, or more) they enter the neighbouring orifice 
 of the sporangium, which they fill almost entirely, penetrating through 
 the portion of the cutaneous layer remaining, which, though without 
 any definite boundary, offers a solid resistance to their further penetration 
 into the sporangium. The corpuscles continue thus to struggle forwards 
 into the cutaneous layer for more than half an hour, bounding against 
 its outer surface they retreat, again push forwards, again retreat, and 
 so on, in an uninterrupted succession of assaults and retreats. 
 
 After this commotion has lasted some time, an abrupt boundary line 
 suddenly appears in the outer aspect of the cutaneous layer, the first 
 indication of a tunic forming around the contents of the sporangium 
 which were before bare. From this moment the mobile corpuscles are 
 separated fi'om the cutaneous layer by a membrane which efEectually 
 prevents their further action upon the contents. They continue, it is 
 true, to move to and fro, and this movement often lasts for hours 
 together, but at last they perish in the rostrum itself. Even after the 
 lapse of several hours the dead ooi-pusoles may be seen in the rostrum, 
 lying on the front of the sporangium, until at last they are completely 
 dissolved, and all vestige disappears. 
 
 The cutaneous layer surrounding the gi-een contents of the sporangium 
 becomes transformed, after impregnation, into the coat of the true spore, 
 which, thus formed, represents a large cell occupying the whole of the 
 sporangium, surrounded on all sides by the persistent tunic, which is 
 open in front and prolonged into the rostrum. 
 
 In this condition the spore remains for some time longer without being 
 thrown off from the parent tube on which it was produced, but the 
 colour of its contents gradually becomes paler and paler. The spore is 
 at last rendered quite colourless, and presents in its interior only one or 
 more largish dark brown bodies. When it has lost all colour it is 
 detached from the parent tube, in consequence of the decay of the 
 membrane of the sporangium enclosing it. After some time, say three 
 months, the spore suddenly resumes its green colour, and immediately 
 thereupon grows into a young Vaucheria exactly resembling the parent 
 plant. 
 
 An abstract of the memoir from which the above details were obtained 
 was published in the " Quarterly Journal of Microscopical Science " for 
 1856. (Vol. iv., p. 63). 
 
 During the present winter Mr. Frederic Bates, of Leicester, has called 
 our attention to some plants of V. sessUis, taken from beneath the ice 
 in a pool. The first feature which presented itself was the septation of 
 the threads, many of them being divided into numerous articulations 
 three or four times the length of the diameter in the upper portion of the 
 thread, but longer below. This unusual septation, as it appears to be, 
 was general throughout the gathering, but the threads bearing oogonia 
 were more rarely divided, but sufficiently so to remove any doubt as to 
 the threads being genuine threads of Faueheria, which at first we must 
 confess to have doubted. The question which next arose was as to the 
 purpose for which this septation had taken place, and an answer sug. 
 gested itself in the collection of the cytioplasm into denser masses 
 towards the centre of the cell, with most evident differentiation into oval 
 bodies, resembling zoogonidia in course of formation. The time of 
 observation has been short, but long enough to raise a suspicion in our 
 minds that another form of fructification, by means of zoogonidia, takes 
 place in Vancheria, and the occurrence of germinating spores in vai-ious 
 early stages in the water in which the Vancheria was being preserved, 
 lends strength to this suspicion. It is quite true that YawBheria has 
 been often and patiently studied, and no intracellular swarm-spores 
 detected ; yet it maybe possible that, under certain conditions, they may 
 be produced. We are patiently waiting in hopes of obtaining active 
 zoogonidia. 
 
120 
 
 SIPHOPHYCEiE. 
 
 The plates for this part were all in course of printing when the above 
 observations were being made, so that it was too late to insert figures of 
 the septate threads and their contents. 
 
 PlateXLTI. Figs. 1-20. Impregnation of Vauchenria sessilis after Pring- 
 sheim X 200. 
 
 Figs 1-4. Stages of development of sexual organs before impregnation. 
 Fig. 5. During impregnation. Figs. 6-8. The way in which the female 
 organ opens the cutaneous layer, bursts through, and a portion is con- 
 stricted off. Fig. 9. Approach of spermatozoids before formation of the 
 membrane of the embryo cell. Fig. 10. Point of female organ after 
 formation of the membrane of the true spore. Figs. 11-12. Later con- 
 ditions of spore after impregnation. Figs; 13-16. Male and female 
 organs after impregnation. Fig. 17. Colourless spore after it is detached 
 from the parent tube. Fig. 1 8. Detached spore, which after resting three 
 months has become green. Figs. 19-20. Germination of the green spores. 
 
 a. TuBTrLiGER.E. Antheridia little or scarcely lent. 
 
 1. Vanchexia dichotoma. Lyngi. Sydro. Dan. p. 75, 1. 19. 
 
 Eobust, loosely csespitose, dirty green, or becoming brownish. 
 Thallus very thick, setaceous, nearly a foot long, remotely 
 dichotomous. Oogonia sessile, globose, or ovoid, single, scat- 
 tered, or 2 to 4 to 6 approximating. Oospores, when mature, 
 with a triple membrane, spotted ■with brown. Antheridia single, 
 erect, oral, sub-clavate, or acute, on the same or on different 
 threads. — Babh. Alg. Eur. iii. 268. 
 
 Size. Oogonia •! mm. diam. Threads '2 mm. diam. 
 
 Walz in Pringsh. Jahrb. p. 152, t. xiy. f. 28-33. Fl. 
 Danica t. 1724. Harv. Man. p. 147. Grev. Br. Alg. p. 190. 
 Gray. Arr. i., 289. Kirsch. Alg. Schl. p. 82. Eng. Bot. ii., t. 
 2418. Grev. Fl. Ed. 305. Mack. Hib. 233. Fl. Devon ii., 
 56. Kutz. Tab. vi., t. 56a. Hass. Alg. t. 4, f. 1. Eng. Fl. v., 
 p. 319. Nordst. Bot. Not. 1879, p. 184. Jenner Fl. Tanb. 
 WeUs, 176. 
 
 Conferva dichotoma, Linn. Spec. 1635. Dillw. Conf. t. 15. 
 Eng. Bot. t. 932. Hnds. Fl. Ang. p. 593. Withering iv., p. 
 49. Hull Br. Flora, 330. 
 
 Vaucheria globifera, De Bary Monats. 1856, p. 589. Babh. 
 Alg. Ex. No. 640. 
 
 Vaucheria salina, Kutz. Tab. vi., t. 66, f. 2. 
 
 Conferta Plinii setis porcinis, Bay. Syn. 58. 
 
 Conferva dichotoma setis porcinis, Dillen. Muse. 17, t. 3, f. 9. 
 
 var. fi submazina. Ag. Syst. p. 171. 
 Vaucheria submarina, Berk. Glean, p. 24, t. 8. Harv. Phyc. 
 Brit. t. 350 B. Harv. Man. 147. 
 
 In ditches, and in brackish and salt water. 
 
 Hassell was of opinion that this species did not differ specifically from 
 Vaucheria sessilis, but the two are now regarded as belonging to different 
 sections. Nordstedt says that it is dicecious, but no reference is made to 
 this fact by Walz. 
 
vauoheeiaobjE. 121 
 
 Plate XLVI. fig. 21. Oogonia of Vaucheiia dickctoma X 100 diam. 
 Fig. 22. Oogonium X 200. Fig, 23. Autheridea X 100. Fig. 24. An- 
 theridium X 200, after Woronin. Fig. 25. Germinating spore. 
 
 Flate XLIX. Jigs. 5, 6. The 7. suhnarina, Berk., generally referred 
 to this species as a variety. 
 
 2. Vaucheiia aversa. Hass.Alg, t. 6,/. 5. 
 
 Loosely csespitose, sparingly branched, expanding in all 
 directions, organs of fructification similar to those of V. sericea, 
 but with the thallus much thicker, the oogonia larger, and sub- 
 erect, now and then somewhat pedicellate ; oospores much 
 smaller. 
 
 Hass. Ann. Nat. Hist. xi. (1843), p. 429. Walz in 
 Prings. Jahrb. p. 151, 1. 13, f. 25-27. Oleve. Vauch. 133, f. 7. 
 
 Vaucheria rostellata, Kutz. Tab. vi., t. 58, f. 4. 
 
 In ditches, 
 
 Hassall describes this species as '' Capsules usually in pairs, and in the 
 form of a bird's head, with the beaks averted from each other. Sporangia 
 circular, not entirely filling the cavity of the capsule." To this he adds, 
 " It is one of the best marked, and most peculiar of the genus, the beaks 
 of the capsules being turned in opposite directions, at once distinguish it 
 from all other known species, in which, when the vesicles are in pairs, 
 they are directed towards each other. This averted position of the 
 capsules renders the existence of a distinct horn or anther essential for 
 each. In the form of the seed-vessels and in the circumstance of the 
 sporangia not filling the entire cavity, the species resembles F. ornitlio- 
 cephala " (now regarded as a variety of F. sessilis). 
 
 Plate XLVll.ifig. 1. Oogonia and antheridia of Vaucheria aversa X 
 100. Fig. 2. The same X 200. Fig; 3. Mature oospore in oogonium X 
 200, after Walz. 
 
 3. Taucheiia soxicea. Lyngb. Hydro. San. i. 21, B. 
 
 Tufts densely interwoven, yellowish, dirty green, or becoming 
 brownish ; thallus thin, loosely and vaguely branched ; oogonia 
 2 to 6 in a series, one sided, oblique oval, rostellate, mouth pro- 
 duced laterally, sessile or shortly pedicellate ; antheridia cylin- 
 drical, or rather clavate, horizontally deflexed. Spermatozoids 
 oblong, with a red spot, furnished with a cilium at each pole. 
 
 Size. Oogonia '1 mm. diam. 
 
 Walz in Prings. Jahrb. p. 150, t. xiii., f. 20-24. 
 
 Vaucheria ornithocephala, Ag. Sp. Alg. p. 467. Grey. Alg. 
 Br. p. 193. Harv. Man. p. 148. Rabh. Alg. Exs. No. 1100. 
 Nordst. Bot. Not. 1879, p. 184. 
 
 Vaucheria polysperma, Hass. Ann. Nat. Hist. xi. (1843), 
 429. Hass. Alg. t. 6, f. 6. Kutz. Tab. vi., t. 58, f. 5. Rabh. 
 Alg. Exs. No. 1375. Oleve Vauch. p. 7. 
 
 In ditches, &c. 
 
122 
 
 SIPHOPHYCB^. 
 
 This is the Vaucheria polysperma of Hassall, who says of it : " It is by 
 no means uncommon, and may be distinguidied fi'om all others known 
 to me by the fineness of its filaments, which are not half so large as those 
 of our other British species, no less than by the form and arrangement of 
 the sporangia. These are slightly pedunculate, varying in number from 
 3 to 5, but usually there are but three, the apices or beaks of which are 
 neither turned towards or averted from each other, but are all directed 
 one way. The resemblance which the capsules bear to a bird's head 
 when viewed sideways is very remarkable, and this resemblance is 
 rendered still more striking by the fact that the circular sporangium 
 occupying only the central portion of each, and which therefore repre- 
 sents the eye of the bird. ' 
 
 Plate XLVII., Jig. 4. Oogonia and antheridia of V. sericea X 
 200. Fig. 6. Oogonia containing oospores x 200. Fig. 6. Mature 
 oospore enclosed in an oogonium x 200, after De Bary. Fig. 7. Zoospore 
 X 200, after Walz. Fig. 8. Spermatozoids. 
 
 b. CoBNicuLAT^. Antheridia bent in the form of a horn or a 
 hook, seated on short lateral branches. 
 
 4. Taucheiia Dillwynl. Ag. 
 
 Terrestrial, broadly expanded, forming a rather thin stratum, 
 of bright or dark green colour. Oogonia globose, or ellipsoid, 
 rostrate, sessile, usually single, sometimes in twins, enclosed in 
 delicately punctate membrane. Mature oospores spotted with 
 brown, sporoderm very thick, composed of several strata. 
 Antheridia bag-shaped, formed from the apices of short lateral 
 curved branches, either approximate to the oogonia or seated 
 between a pair of them. 
 
 Rabh. Alg. Eur. iii., 269. Giev. Alg. Britt. t. xix. Hass. 
 Alg. t. 4, f. 3. Eng. Fl. v., p. 320. Jenner Tunb. Wells 176. 
 Eng. Bot. ii., p. 124. Harv. Man. 147. Johnst. Fl. Berw. ii., 
 251. Grev. Fl. Edin. 305. Mack. Hib. 234. Fl. Devon ii., 
 56. Hook. Fl. Scot, ii., 93. Gray Arr. i., 290. 
 
 Vaucheria Ungeri, Thnr. Ann. Sci. Nat. xix. (1843), t. 13, f. 
 43? 
 
 Vaucheria pachyderma, Walz Jahrb. p. 146, 1. 12, f. 1-6. 
 
 Conferva frigida, Dillw. Conf. t. 10. Harv. Man. p. 147. 
 
 Conferva amphibia fibinllosa at spongiosa, Ray. Syn. p. 69. 
 
 On the ground in damp shady places. 
 
 It is presumed that this is the same species as has been described by 
 Walz under the name of Vancheria pachyderma, but the synonyms of some 
 of these species are a little mixed. Dillwyn says : " It is not unfrequently 
 found in turnip fields during the winter and early months of the spring, 
 particularly in a northern exposure, and on a cold soil. The patches 
 vary in size, but are usually two or three inches in extent, adhering but 
 slightly to the soil, and consistlug of loose unconnected filaments." 
 " The form of the capsules, which are rarely pedunculated, will at once 
 distinguish this from all other species," says Hassall, "which have 
 hitherto been described." 
 
VAUCHEEIACE^. 123 
 
 Plate XLVJI., Jigs. 9, 10. Oogonia and antheridia of V. Dillwyni x 
 200. Fig. 11. Oogonium of the same X 200. Fig. 12. Mature oospore 
 enclosed in membrane of oogonium x 230, after Walz. Fig. 13. Sper. 
 matozoids, 
 
 5. Tauchezia sessilis. VaucJt. Oonf.p. SI. pi. 2,f. 7. 
 
 Loosely intricate, pale or rather dull green. Thallus capil- 
 lary, sparingly branched ; oogonia 2 to 3 approximate, rarely 
 single, oyate or oblong-OTal, more or less oblique, rostrate ; 
 antheridia intermediate, either short, hamate, or straight and 
 subulate, or a little clarate, sometimes elongated and in- 
 curved, rarely circinate. Mature oospores punctate with 
 brown, involved in a triple membrane. 
 
 Size. Oospore -07 mm. diam., thread -07 mm. (Cleve). 
 
 Eng. Fl. v., 320. Cleve Vauch. 133, f. 6. Kirsch Alg. 
 Schl. 82. Walz Vauch. p. 145. Kutz. Tab. vi., 59, f. 2. 
 Hass. Alg. t. 4, f. 2. Eng. Bot. t. 1765. Harv. Man. p. 148. 
 Grev. Alg. Br. p. 192. Jenner Tunb. Wells 176. 
 
 Vaucheria sphcerocarpa, Kutz. Tab. vi., t. 59, f. 1. 
 
 Vaucheria racemosa, Rabh. Alg. Sachs. No. 495. 
 
 Vaucheria Ungeri, Thur. Ann. Sci. Nat. xix. (1843), t. 11, 
 ]2, 13, f. 37-42 and 44. 
 
 Sporangia. — 
 
 Vaucheria clavata, Vauch. Conf. t. 3, f. 10. Hass. Alg. 
 59, t. 2, f 20-33. Harv. Man. 149. Berk. Glean, t. 10. 
 Gray. Arr. i., 290. 
 
 In ditches, or on the ground. 
 
 vwr. a. ceespitosa. Vauch. Conf. p. 26, t. 2, /. 4. 
 
 Oogonia usually in pairs, ovate, opposite. Antheridia in- 
 termediate, generally short,- circinate. 
 
 Vaucheria ccespitosa, Carm. Eng. Fl. v., p. 321. Eng. Bot. 
 1, t. 2841, ii., t. 2421. Hook. Fl. Scot, ii., 92. Jenner 
 Tunb. Wells, 176. Grev. Alg. Britt. 194. Harv. Man. 148. 
 Johnst. Fl. Berw. ii., 251. Hull Br. Fl. 330. Abbot. Bedf. 
 275. Mack. Hib. 234. Gray Arr. i., 291. 
 
 Conferva amphibia, Dill. Conf. t. 41. With. Arr. iv., 129. 
 Hiids. PI. Ang. ii., 594. Lightf. Fl. Scot. 979. Sibth. Ox. 
 336. 
 
 Conferva amphibia fihrillosa et spongiosa, Dill. Muse. t. 4, f. 17. 
 
 Conferva terrestris exilis fibrillosa, Ray. Syn. 59. 
 
 On the margins of streams or pools. 
 
 " Fronds densely interwoven into cushion-like tufts or strata of in- 
 definite extent, irregularly branched, the tips erect, giving the surface the 
 appearance of bright green velvet." — Rirvey. 
 
 Dillwyn's description of his Conferva amphibia seems to be most appli- 
 cable to this species. " On the edges of ditches, and in similar situations, 
 it frequently occurs in masses so densely matted as to hold water like 3 
 
124 siphophtcbjB. 
 
 sponge, with its surface beset by erect branches which give it a very 
 bristly appearance. In this state it is well known to botanists as the 
 C. amphibia of all modem authors. Its hue is of a bright green, 
 becoming ash-coloured with age. ITie root I have not been able to dis- 
 cover, and the entangled mode of its growth renders it impossible to 
 ascertain the length of the filaments. These are repeatedly divided with 
 distinct patent branches, which, as before mentioned, when the plant 
 grows in shallow water, so that some of them are exposed to the air, send 
 out patent ramuli, of a stunted growth, from being out of their proper 
 element, which by their ereotness give the plant its bristly appearance; 
 yet at the same time, if whilst in this state the waters rise so as to over- 
 flow the plant, their length is gradually increased, and losing their erect 
 position they yield to the curreat, and become the Ceramium ccespitosum 
 of Both ; and after having thus changed, if by the subsidence of the 
 waters the surface is again exposed to the air, the filaments, of course 
 disposed horizontally, give the plant a bristly appearance by again throw- 
 ing out erect patent ramuli." 
 
 var. oznithocephala. Hassall Alg. t. 6, /. i. 
 
 In dirty green tufts, densely imbricated, and becoming paler. 
 Thallos loosely branched. Oogonia solitary, or in pairs, oval- 
 oblong, obliquely rostrate, beaks truncate, antheridia cylindric- 
 subulate, incurved, interposed, usually exceeding in length the 
 diameter of the oogonia. 
 
 Vaucheria omithocephala, Eng. Fl. v., 320. Harv. Man. 
 148. Hook. Fl. Scot, ii., 93. Eng. Bot. ii., p. 195. Grev. 
 Alg. Britt. 193. Grev. Fl. Ed. 306. Fl. Devon, ii., 56. 
 Gray Arr. i., 291. 
 
 Conferva vesicata, DUlw. Conf. t. 74. 
 
 In stagnant or slow-flowing water. 
 
 var. zepens. Hassall Alg. t. G, f. 7. Ann. Nat. Mist. XI., 430. 
 
 Terrestrial. Oogonia single, sessile, oblong or ovate, shortly 
 rostellate, mouth lateral, truncate. Antheridia solitary, next 
 the oogonium, cylindric-clavate, erect, inclined or curved, 
 scarcely longer than the oogonium. 
 
 On the naked ground. 
 
 It is on Vaucheria sessilis that Sir J. E. Smith says are found th 
 " Vesicles of the nature of galls, perhaps, inhabited by Muller's Cyclops 
 lupula," figured on plate 2419 of the second edition of English Botany. 
 Hassall states that the species is V. geminata, but this is accounted for 
 by the belief which was current in those days that T. geminata was the 
 summer form of Y. sessilis. — See £ng. Bot. ed. u., p. 125. 
 
 Plate XLVI., figs, 1 to 2P. Impregnation of Vaucheria sessilis, after 
 Pringsheim x 200. 
 
 Vlate XLVIII.^ fig. 1, part of thread, with sexual organs, of V. sessilis. 
 Fig. 2, oogonia and antheridia x 200. Fig. 3, oogonia and antheridium 
 of the variety coespitosa X 300. Fig. 4, oogonia and antheridium of the 
 terrestrial variety repens x 200. Fig. 5, thi-eads bearing sporangia at the 
 tips slightly magnified. 
 
vaucheriaoejE. 125 
 
 6. Taucheiia geminata. (Vauch.) Wah. Jahrh. p. 147, t. 12, f. 7-11. 
 
 Dark or dull green, in dense intricate tufts. Thallus capil- 
 lary, tough, dichotomous. Oogonia two (rarely 1 or 3), 
 ovate or oboTate, opposite, distinctly pedunculate. Antheridia 
 intermediate, subulate, more or less reouryed. Mature oospore 
 spotted with brown, sporoderm colourless, composed of three 
 strata. Sporangia on the same or a proper thallus, broadly 
 cup-shaped, truncate, and angularly horned. 
 
 Size. Oospore •11--12 x 'IS-'IO mm. 
 
 DCand. Fl. Fr. ii., 62. Hass. Alg. t. 3, f. 1. Cleve Vauch. 
 p. 6, f. 4. Kirsch. Alg. Schl. p. 83. Kutz. Tab. Phyc. vi., 
 t. 59, f. 3. Eng. Fl. v., 320. Harv. Man. 148. Eng. Bot. 
 i., t. 1766, ii., t. 2420. Grev. Alg. Britt. p. 193, t. 19. 
 Purton Mid. Fl. ii., 611. Johnst. PI. Berw. ii., 252. Grev. 
 PI. Ed. 306. PI. Devon, ii., 56. Gray Arr. i., 291. 
 
 Ectosperma geminata, Vauch. Conf. 29, t. 2, f. 5. 
 
 Vaucheria Dillwyni, Rabh. Alg. Sachs. No. 1078. 
 
 To this species we also refer the following as synonyms, 
 although usually referred to V. sessilis: — ■ 
 
 Vaucheria ovoidea, Hass. Alg. 57, t. 5, f. 3. 
 Vaucheria ovata, Gray Arr. i., 289. 
 
 Ectosperma ovoidea, Huds. PI. Aug. 954. Hook. Fl. Scot. 
 979. With. Arr. iv., 129. 
 
 In ponds and ditches. 
 
 var, j3 xacemosa. 
 
 Oogonia shortly pedunculate, 3 to 5 or more aggregated 
 in a corymbose manner. Antheridia single, scarcely longer 
 than the oogonia. 
 
 Size. Oospore •06--08 x ■075--08 mm. 
 
 Vaucheria racemosa, Eng. Bot. ii., 126. Grev. Alg. Britt. 
 195. Harv. Man. 149. Grey. Fl. Ed. 306. Gray Arr. i,, 
 292. Hass. Alg. 56,. t. 3, f. 2. 
 
 We have reproduced Hassall's figure of this form in which the antheri- 
 dium is considerably longer than the oogonia. Vauoher says, "This 
 species is one of the most common, and is found in nearly all ditches, 
 principally in the spring. It is loaded with little bouquets manifest to 
 the unassisted sight, and which with the microscope seem to be formed of 
 a common peduncle, subdivided into pedicels, each of which carries on 
 its summit a spherical body in every way resembling the grains of other 
 eotosperms, but nearly half as small again. In the middle of this 
 bouquet is the horn, which, without doubt, performs the function of a 
 male flower, and which is here but a prolongation of the peduncle. The 
 number of grains varies from 5 to 7, but commonly 4 are met with." 
 
 It is of this species that Hassall says, " It is most frequently infested 
 with the curious parasite Cyclops lupula of MuUer, which occasions the 
 growth on the filaments of such extraordinary-looking appendages, in 
 the midst of which the parasite resides." This parasite, whatever it may 
 be, was the subject of a communication by Mr. A. Lister to the Essex 
 Field Club, July 22, 1882, and will be found in the " Proceedings " of the 
 Club (Vol. iii.). 
 
126 SiPHOt'HYCEJS. 
 
 Plate XLYlll.,Jigs. 6.7. Oogonia and antheridia of V. geminaia. X 
 200. Fig. 8, non-sexual spores of the same X 200, after Walz. Fig. 9, 
 mature oospore x 200. 
 
 Plate \XL1X., fig. 4, fruiting branch of the variety racemosa, after 
 Hassall. 
 
 7. Tauchezia hamata. {Vauch) Walz. p. 148, t. Xll./. 12-17. 
 
 Aqnatic or terrestrial, thallus rather rigid, vaguely branched. 
 Oogonia usually single, ovate or ovate-liemisphserical, seated 
 on a short segment of the divided stem, the other segment 
 elongated, curved, forming the antheridium. Mature oospores 
 involved in a sporoderm formed of four or more strata. 
 
 Cleve Vauch. p. 6. Hassall Alg. t. v., f. 1. Gray Arr. i., 
 289. 
 
 Ectosperma hamata, Vauch. Conf. 26, t. 2, f. 2. Hass, 
 Ann. Nat. Hist, xi., p. 439. 
 
 Vaucheria hamulata, Kutz. Tab. Phyc. vi., t. 61, f. 2. 
 
 In ditches. 
 
 Taucher wrote of this species — " It differs from all others by the 
 manner in which it carries its grains. The peduncles which sustain them 
 are much elongated, and they bear at their extremity two little threads, 
 the one is recurved and receives the anther, the other is shorter and 
 straighter, and carries the grain." 
 
 Plate XLVIII.,fi^s. 10, 11. Oogonia and antheridia of V. hamata X 
 200. Figs. 12, 13, mature oospores free from oogonia X 200. Fig. 14, 
 sporangium X 200. 
 
 8. Vaucheria tenestris. Lyngh. Hydro. Dan. p. 77, *. 21, f. A. 
 
 Densely interwoven in a thin bright emerald stratum. 
 Oogonia usually single, pedunculate, attached by the flattened 
 base at the back of the incumbent elongated curved antheri- 
 dium. Mature oospores enclosed in a hyaline colourless sporo- 
 derm composed of four strata, considerably inflated. 
 
 Eng. Flora v., 320. Grev. Alg. Britt. p. 191. Eng. Bot. 
 ii., p. 124. Jenner Tunb. Wells, 176. Harv. Man. 148. 
 Johnst. Fl. Berw. ii., 251. Mack. Hib. 234. Gray Arr. i., 
 290. Hass. Alg. 53, t. 5, f. 2. Berk. Glean, t. 9. Walz. 
 Jahrb. p. 149, t. xiii., f. 18, 19. Rabh. Alg. Eur. p. 270. 
 Cleve Vauch. 131, f. 1. 
 
 Ectospei-ma terrestris, Vauch. p. 27, t. 2, f. 3. 
 
 Vaucheria circinata, Kutz. Tab. vi., t. 60, fig. 2. 
 
 Forming patches on damp and clayey soil. 
 
 " Threads more straight and rigid than in V. Dillmyni, forming a more 
 lax and less interwoven stratum, the summits of the little branches often 
 erect, and giving the whole a bristly appearance." — Oreville. 
 
 Plate XLIX. Jigs. 1,2. Oogonium and antheridium of V. terrestris X 
 200. Fig. 3, mature oospore of same, after Walz X 230. 
 
 Plate XLIX., Jig. 7. Oogonium of V.velvtina, Ag. (a, marine species), 
 after Harvey X 20O. 
 
NEMATOPHYCEiE. 127 
 
 Order IV. NEMATOPIIYGEM. 
 
 Multicellular algse, chlorophyllose, membranaceous or fila- 
 mentous, with or without branches. Vegetation either terminal, 
 limited or unlimited, forming an articulate thread, or in the 
 beginning terminal, and afterwards lateral, forming a mem- 
 branaceous thallus of a single stratum. Cell multiplication by 
 repeated division in one or two directions. 
 
 Propagation by oospores, or by zoogonidia. 
 
 Divided into the following families : — 
 
 A. Vegetation by division of the cells at first in one, and 
 afterwards in two directions, forming a membranaceous thallus. 
 
 Family I. Ulvace^. — Thallus membranaceous formed of one 
 stratum of cells, either plane or expanded, or tubular, or saccate. 
 
 B. Vegetation by division of the cells in one direction, 
 forming a cellular series or articulate thread. 
 
 Family II. — SpH-EROPLBiB. — Articulate thread not branched, 
 articulations greatly elongated, cylindrical, multilocular, chloro- 
 phyll mass distributed in ring-like bands. 
 
 Propagation by resting spores, which, before germination, 
 break up into zoospores. 
 
 Family III. Confervaoe^. — Articulate thread, simple or 
 branched, vegetative articulations cylindrical, fructiferous always 
 more or less swollen. Chlorophyllose mass effused, or parietal, 
 often more or less regularly spiral. 
 
 Propagation by macro- and micro-gonidia. 
 
 Family IV. PiiHOPHORACEiB. — Cladophora-like plants, 
 with terminal vegetation. Articulate threads branched. 
 
 Propagation by neutral, quiescent, cask-shaped spores 
 (agamo-hypnospores). 
 
 Family V. OEDOGONiACEiE. — Articulate thread either 
 branched or not branched ; articulations short. 
 
 Propagation by oospores after sexual fecundation. 
 
 Family VI. IJLOTKicHEiB. — Articulate thread not branched, 
 sometimes laterally connate ; articulations short, at times very 
 short. 
 
 Propagation by macro- and micro-gonidia. 
 
 Family VII. CHEOOLEPiDiE. — Aerial algse. Articulate 
 thread branched, cell membrane firm, filled with an equally dis- 
 tributed oleaginous golden or reddish endochrome. 
 
 Propagation by zoogonidia. 
 
 Family VIII. Ch^etophobejs. — Aquatic alg». Articulate 
 thread dichotomously branched, ramuli sometimes aggregated in 
 a fasciculate or penicellate manner. Chlorophyllose mass 
 usually collected in transverse bands. • 
 
 Propagation by zoogonidia. — Bahh. Alg. Eur. iii, 286. 
 
 T 
 
128 NEMATOPHTCB^. 
 
 Family I. ULVACE^. 
 
 Thallus membranaceous, or foliaceous, rarely crnstaceous, 
 formed of one stratum of cells, either expanded, or tubulose, or 
 Tesiculose. 
 
 Propagation by zoogonidia, arising from a repeated division 
 of the cytioplasm, Zoogonidia oblong, furnished at one ex- 
 tremity with two or four cilia. 
 
 8uh-FamiIy 1. Peasiole^. 
 Thallus expanded and foliaceous, rarely crustaceons. 
 Genus 54. FHASIOLA. Ag. (1821.) 
 
 Thallus membranaceous foliaceous, ascending or erect, more 
 or less crispate, composed of angular cells, distributed in plane 
 areas ; base sometimes loosely fibrillose. 
 
 Vegetation by division of the cells in two directions. 
 
 Pxasiola crispa. Kutz. Tab. Phyc. V. t. 40, /. 6. 
 
 Tufts more or less dense, often long and widely expanded, 
 dark green, soft and elastic. Thallus plicate crisped, of variable 
 form and size, often bullate ; cells arranged in distinct areolas, 
 or confluent, quadrate, or oblong-quadrangular, now and then 
 twice as long as the diameter ; angles more or less obtusely 
 rounded. 
 
 Size. Cells -OOS-'OOO mm. diam., or -OOS-'OIS mm. x 
 •003--005 mm. 
 
 Jessen Mon. Pras. 1. 1, f. 10-16. Kabh. Alg. Eur. iii, 308. 
 Lagerstedt, Pras. p. 19. 
 
 Ulva crispa, Hass. Alg. t. 78, f. 12. Eng. Flora v., p. 312. 
 Eng. Bot. ed. i, 2754 ; ed. ii, 2406. Lightf. Fl. Scot. 972. 
 Harv. Man. 171. Grev. Fl. Edin. 299. Hook Fl. Scot, ii., 91. 
 Mack. Fl. Hib. 243. Hull Br. Fl. 309. Abbot. Fl. Bedf. 273. 
 Johnst. Fl. Berw. ii., 250. Jenner. Tunb. Wells 190. 
 
 Ulva lactuca y, Huds. Fl. Ang. p. 567. Dillen. Muse. t. 9, 
 f. 6. 
 
 Ulva terrestris, Gray. Arr. i., 344. 
 
 Tremella crispa, With. Arr. iv., 81. 
 
 On damp ground, rocks, &c. 
 
 Haasall unites this species and the next together in one, bnt his 
 example has not been followed by his successors. 
 
 Common on moist, shady ground, especially near honses and walls, 
 sometimes on old thatched roofs. Fronds very mnch crowded, forming 
 a dense stratum, rather lying on the soil or medium than attached to it ; 
 deep green, rounded, thin, tender, but not gelatinous, variously curled 
 
tJLVAOEJS. 129 
 
 and folded. Quaternate granules beautifully arranged iu squares, oon- 
 tained in larger ones, and separated by parallel pellucid lines, the -whole 
 compared by Agardh to the walks and parterres of a garden. Annual. 
 Found throughout the winter and early spring. — Eng. Bot. p. 111. 
 
 Plate L. fig. 1. Plants slightly magnified. Fig. 2, portion of a frond 
 X 400. 
 
 Piasiola fuzfuxacea. Menegh, Oenni. p. 86. 
 
 Forming a furfuraceous stratum, more or less expanded, dark 
 green. Th alius about a line long and broad, dilated from the 
 short stem-like base into a fan-like lamina ; margin slightly 
 undulate and lepand, often emarginate at the apex or lobed. 
 Cells angular, arranged in regular quadrate, or almost quadrate 
 areolas. 
 
 Size. Cells •014--016 X •004--006 mm. 
 
 Jessen, Mon. Pras. t. 2, f. 1-10. Eabh. Alg. Eur. iii., 309. 
 Lagerstedt Pras. p. 32. 
 
 Ulva furfuracea, Grey. Sc. Crypt. Fl. t. 265. Eng. Fl. v., p. 
 312. Hary. Man. 171. Eng. Bot. ed. ii., p. 112. Grev. Alg. 
 Britt. 176, t. 18. Mack. Fl. Hib. 244. 
 
 On damp walls and rocks. 
 
 " Fronds closely tufted, forming a rivid green stratum, a yard or more 
 in extent, two or three lines in length, erect, obovate, truncated, and 
 usually eroded at the top, tapering at the base into a longish claw ; 
 margin inflected , substance firm, and void of lubricity. Cells in fours. 
 It does not adhere to paper." — Carm. 
 
 Plate L. fig. 5. Fronds slightly magnified. Fig. 6, young frond X 400. 
 Fig. 7, lower portion of mature frond X 400. 
 
 Fzaaiola stipitata. Suhr. in Jessen Mon. t. 2,f. 11-16. 
 
 Stratum csespitose, expanded, dark green. Thallus of 
 variable form and size, commonly one to two lines, rarely four 
 lines long ; dilated upwards from a stem-like base (lanceolate, 
 obovate, obcordate, reniform, flabelliform, &c.), often truncate 
 at the apex ; margin slightly repand ; cells in the stem-like 
 base in series, in the upper part disposed in small regular 
 areolas. 
 
 Size. Cells -OOS-'OO? mm. 
 
 Jessen, Prasiola p. 16, t. 2. Eabh. Alg. Eur. iii., 309. 
 Lagerstedt. Pras. p. 36, fig. 4. 
 
 On rocks by the sea, &c. 
 
 Jessen, in his monograph of this genus, gives figures of the fronds of 
 some Irish specimens of the above species, which he had seen and 
 examined. It is, on the faith of this, included here, although it appears 
 to be the most marine of any of the four. 
 
 Plate L. figs. 8. 9. Fronds of P. stipitata magnified i diam. Fig. 10, 
 young frond X 400. Fig. 11, part of mature frond X 400. All after 
 Jessen. 
 
] 30 NEMATOPHYCB^. 
 
 Pxasiola calophylla. (Spreng.) Menegh. Cenni. p. 36. 
 
 Csespitose, dark green, crispate ; th alius 2-4 lines long, 
 narrow, linear, rather circinate, attenuated at the base into a 
 stem, truncate at the apex, now and then crenate ; cells large, 
 arranged in longitudinal series. 
 
 Size. Cells •004--005 x ■002-'004 mm. 
 
 Jessen, Mon. Pras. t. I, f. 1-3. Lagerstedt. Pras. p. 40. 
 
 Ulva calophylla, Hass. Alg. 298, t. 77, f. 1. Eng. Fl. v., 
 312. Gre7. Alg. Britt. p. 176. Eng. Bot. ed. ii., p. 112. 
 Harv. Man. 171. Johnst. Fl. Berw. ii., 251. Mack. Hib. 243. 
 
 Bangia calophylla, Carm. in Grev. S. Crypt. Fl. t. 220. 
 
 On damp stones, rocks, &c. 
 
 " Forms a bright green thin stratnin. Frond minnte, three or fonr 
 lines long, linear strap-shaped, obtnse, tapering at the base, or saddenly 
 contracted into a cylindrical stipes, much waved and cnrled, very 
 variable in breadth. Granules qnaternate, closely covering the frond ; 
 set in longitudinal rows, of which two or more (sometimes half a dozen) 
 form the breadth of the frond j interstices colonrless." — Hwrvey. 
 
 Plate L. fig. 3. Plant magnified slightly. Fig. 4, lower portion of frond 
 X400. 
 
 Sub-Family 2. ULVEis. 
 Th alius membranaceous, vesiculose, or tubulose. 
 
 Gentts 55. ENTEROIIIIO&PH&. Link. (1820.) 
 
 Thallus membranaceous, tubular or utricle-shaped, fixed at 
 the base (usually at the first, but afterwards often free 
 swimming) ; composed of one stratum of cells, sometimes 
 branched, but rarely much branched. 
 
 Propagation by zoogonidia, produced by repeated division of 
 the cytioplasm, rostrate at one extremity, and furnished with 
 two cilia. 
 
 Entezomoiphaintestinalis. (Zinn.) Link. Hor. Ber. {1820.) 
 
 Fronds simple, elongated, variable in form and size, usually 
 becoming more or less inflated, obtuse above, attenuated at the 
 base, pale green ; cells 3-5-6 angled. 
 
 Size. Cells •012--02 mm. diam. 
 
 Eng. Fl. v., p. 314. Jenner, Tunb. Wells 190. Eng. Bot., 
 ed. ii., t. 2408. Hass. Alg. 303, t. 77, f. 2. Grev. Alg. Britt. 
 179. Harv. Man. 173. Mack. Fl. Hib. 242. Wyatt. Alg. 
 Exs., No. 80. Eabh. Alg. Eur. iii., 312. 
 
 Ulva marina tubitlosa intestinorwnjiguram. Ray. Syn., 62. 
 
 Tremella marina tuhulosa, etc. Dillen. Muse, t. 9, f. 7. 
 
 Viva intestinalis. Huds. Angl. 568. Light. Fl. Scot. 
 968. Kelh. Cant. 443. Purt. Midi. Fl. ii., 617. Hook. Fl, 
 
ULVACEiE. 131 
 
 Scot, ii., 91. Jolinst. Fl. Berw. ii, 249. Hull, Br. Fl. 311. 
 Abbot Fl. Bedf. 273. With. Arr. iv., 125. 
 
 Scytosiphon intestinalis. Gray, Arr. i., 345. 
 
 Enteromorpha lacustris. Hass. Trans. Linn. Soc. 
 
 Fistularia intestinalis. Grev. Fl. Edin. 300. Fl. Devon, 
 ii., 57. 
 
 In ditches, chiefly in brackish water. 
 
 This exceedingly variable species has many forms or varieties to ■which 
 names have been given, one of which by rupture of the apex, is funnel- 
 shaped (var. Oornucopice), others are more or less thread-like, and others 
 inflated and bullate. Root a minute scutate disc. Frond from a few 
 indhes to one or more feet in length, and from a line to three or four 
 inches, or more, in diameter ; tubular, obtuse, tapering at base to little 
 more than the diameter of hog's bristle, gradually becoming inflated 
 upwards, and in old age often swelling out into a large membranous 
 bag, which is variously ousped and curled. Sometimes the whole frond 
 is compressed and very much crisped ; substance thin and membranous, 
 but not gelatinous, not closely adhering to paper in drying. Colour 
 varying from a transparent yellowish green to a dull grass green; in old 
 age and decay fading to a dirty white. Under the microscope a portion 
 of the frond OKhibits the appearance of a transparent membrane covered 
 with green unequal angular cells. — Ha/rvey. 
 
 It occurs on the sea shore, in tidal rivers, and ditches connected with 
 them, whether salt, brackish, or freshwater, sometimes at a considerable 
 distance from the sea. In this respect it differs from Enteromorpha 
 compressa, which is not found in fresh water, and has therefore no claim 
 to be inserted in the present work. 
 
 Flate LI. Jigs. 1, 2. Small fronds of Ent. intestinalis, natural size. 
 Fig. 3, the variety CornuoopicB, nat. size. Fig. 4, ceUs X 400. Fig. 5, 
 zoogouidia. 
 
 Genus 56. MONOSTROiaA. Thur. (1854.) 
 
 Frond plane or saccate, simple or torn and lobate, composed 
 
 of one stratum of cells, cells somewhat rounded (sometimes 
 
 quaternate) immersed in a homogenous membrane. — Thuret,Note 
 
 sur la synonymie des Ulva, ^c. 
 
 This genus was formerly included in Z/Zoa, from which it was separated 
 by Thuret. See also Monograph of Momstroma, by Prof. T. Wittrook. 
 The majority of species are marine. 
 
 nXouostzoma laceratum. Thur. Note sur Ulv. 
 
 Thallus membranaceous, at length free, thin and flaccid, pallid 
 green, of irregular form, rugose, margin plane and eroded, or 
 crisped (•04--05 mm. thick) ; cells rounded, twin, ternate, or 
 quaternate, disposed loosely in the intercellular substance, in 
 transverse section of the thallus oval (■017--023 mm. high), 
 chlorophyllose body central, of the same form as the cell, of 
 which it occupies about one-half. — Wittr. Mon. Monostr., p. 
 30, f.1,/2. 
 
 Plate LI., fig. 6. Portion of frond X 200. Fig. 7, section of frond 
 X 200 diam. 
 
132 NEMATOPHYCEiE. 
 
 Blonostroma Wittrockii. Born. Nota Alg. p. VJ&. 
 
 Thallus membranaceous, gelatinous, bright green (18 mill.) 
 oblong, pedicellate, at first saccate, tben open at the summit, 
 margin becoming irregularly lobed. The adult plant becomes 
 sessile, and is attached by apart of its surface, when mature the 
 fronds are large (8 cent, diam.), the lobes plicate, elongated 
 and rounded, cell angular, subquaternate, in section of thallus 
 rounded, chlorophyllose body occupying about half the cell. 
 
 In salt or brackish water. 
 
 Perhaps hardly claiimiig a place in this work, as it is more truly a 
 marine species. 
 
 Plate LI., fig. 8. Portion of a frond X 200. Tig. 9, 10, sections of 
 frond X 200. Fig. 11, zoogonidia X 300. Fig. 1 2, germinating X 200, 
 after Bomet. 
 
 Monostroma lullosum. Wittr. Mon., p. 28, is the Tetraspora 
 bullosa of this work, see p. 16, plate vi., fig. 1. 
 
 Family II. SPH^ROPLEACE^. 
 
 Threads simple, with terminal vegetation, very long, articu- 
 late, articulations cylindrical, by spurious septa multilocular. 
 Chlorophyllose mass distributed in annular bands, which enclose 
 from 3-7 starch vesicles. 
 
 Propagation by oospores after sexual fecundation, very 
 numerous in the cells, at first green, then red, enclosed in a 
 stellate sporoderm. 
 
 Genus 57. SPHAIROPLEa. Ag. (1821) 
 
 Characters the same as given above for the family, which 
 consists but of one genus. 
 
 The following is an abstract of a memoir on SpTusroplea annulina, by 
 Cohn (in the "Ann. des Sci. Nat.," 1856, p. 187), describing the process 
 of fructification : — " The structure of the resting-spores is very singular. 
 They are red spherical bodies, from one 120th to one 100th of a line in 
 diameter, and formed of two hyaline membranes, the interior of which 
 is intimately connected with its plastic contents, whilst the exterior is 
 loose and elegantly plaited. These plaits or folds are so arranged that 
 they meet at their two poles ; often, however, they are very irregular 
 in shape and direction, especially in the larger spores. 
 
 " In germination the resting-spores undergo several modifications. They 
 become granular and change to a dull brown red, and a more transparent 
 circle appears in their centre. Frequently the red matter changes to 
 green before the germination, and this change of colour is gradual, 
 proceeding from the circumference to the centre of tho cavity. At 
 length the whole of the plastic contents divides into two, then into four 
 or eight bodies, which burst the double envelope and disperse in the 
 water as so many zoospores. 
 
SPH^ROPLBACB^. 133 
 
 " The zoospores are of an elegant shape, hnt this is not more uniform 
 than their size or colour. Usually they are globular or shortly cylin- 
 drical bodies, from one 190th to one 150th of a line long, of a beautifal 
 cinnabar or carmine red, and furnished at one of their ends with a small 
 colourless bead bearing two long cilia. Some of them are larger, 
 pyriform or fusiform, aud the result probably of the undivided con- 
 tents of a restlng-spore. Some of the zoospores are two-coloured 
 — red towards the beak, and green throughoat the other part, or 
 the two colours are variously disposed, the colourless bead or beak, 
 and the two cilia are invariably very distinct. The zoospores exhibit 
 a slow jerking movement during several hours. This movement 
 is often interrupted for several hours, when the whirling suddenly 
 recommences. When the zoospores break through the integument 
 within which they are formed, they are not enveloped in cellulose, but 
 already during their period of activity they begin to invest them- 
 selves with a thin elastic pellicle. At the time of their germination this 
 envelope thickens and lengthens in the form of a spindle, the two ends 
 soon tapering ofi into long tails, which even the enlarging body of the 
 zoospore itself separates farther and farther apart. The contents of this 
 germ-cell, at first homogeneous and finally granular, change during this 
 first growth. What is left of the red oil is quickly transformed into 
 chlorophyll, and the plantlet assumes a uniform green colour. Never, 
 theless one may perceive from the beginning a number of vacuoles, or 
 limpid, colourless droplets, in the midst of the protoplasm with which 
 they are filled, and between them the chlorophyll collects in rings more 
 or less distinct from each other. Soon large grains of starch appear in 
 these collections of green matter, so that the plantlet combines all the 
 characteristics of an adult cellule of the Sphcsroplea, even before it has 
 exceeded a 13th of a line in length. The terminal tails have been 
 observed after the plantlet was more than half a line long. Growth 
 takes place in the middle, by the successive division of the older rings. 
 The contents of the adult threads presents the most beautiful appear- 
 ances. It consists of a colourless protoplasm, a green chlorophyll, a 
 watery liquid, and granules of starch ; the whole so disposed that the 
 liquid element forms large vacuoles in a row, like the pearls of a 
 necklet, and the diameter of which is nearly as great as that of the thread 
 itself. Often these vacuoles abut on each other, and seem to give birth 
 to partitions. In the spaces between the pairs of vacuoles the green 
 plasma and grains of starch crowd together, though the space is dis- 
 jointed by the innumerable small vacuoles they throw off. 
 
 ** On approaching fructification the vacuoles multiply to such an 
 extent as to give the endochrome the appearance of a frothy mass, in 
 which the starch granules are irregularly scattered. Soon after the 
 starch granules assemble in pairs or threes or larger numbers, aud 
 around these groups the green plasma becomes more plentiful, so that 
 in time they appear as so many equidistant cysts in the axis of the 
 thread. The greater part of the vacuoles having gradually disappeared, 
 the green clots assume a stellate appearance, connected by green 
 mucous rays or filaments. Between these star-like clots large vacuoles 
 are formed in pairs, which flatten so as to look like partitions, so that 
 each thread seems to be divided into numerous compartments. 
 
 " The green matter contained in these compartments then undergoes 
 modifications, aud the mucous rays are gradually resorbed, the chloro- 
 phyll contracting meanwhile — sometimes to the right and sometimes to 
 the left. In a short time the colourless plasm collects around the chloro- 
 phyll in such a manner that the partitions disappear, and the whole 
 contents of the thread breaks up into a large number of free globular 
 masses, easily distinguished from the ambient colourless mucilage, and 
 containing a certain quantity of irregularly distributed chlorophyll. These 
 
134 NEMATOPHTCEa;. 
 
 are the young spores, which undergo a marvellous variety of transforma- 
 tions. At first they are contiguous, but as they contract they become 
 free, thono^h variable in shape, and with their chlorophyll distributed in 
 a thousand different ways. Finally they become spherical and almost 
 completely filled with chlorophyll interspersed with some starch granules, 
 and covered with a thin, smooth layer of plastic matter, but not with a 
 cellulose membrane. 
 
 " Long before the foregoing process has taken place, the cell-wall 
 proper of the thread has undergone some peculiar chemical alterations, 
 all tending to its final dissolution to free the fnlly-developed spores. 
 Previous to this, however, little apertures are formed in it at certain 
 points, varying in diameter from one 500th to one 300th of a line. 
 
 " All the cellules of the same filament do not undergo the modifica- 
 tions described. In a large number of them the phenomena are quite 
 different, the green rings, interspersed with colourless vacuoles, 
 gradually change to a reddish yellow,, and the grains of starch dis- 
 appear. Soon the coloured matter thus formed becomes granular, and 
 is finally broken up into innumerable rod-like corpuscles." 
 
 Thus the cycle is completed, and we need not pursue the abstract 
 further. Plate LIl. will serve to illustrate the various changes. 
 
 Sphsroplea annulina. (JRot%^ Ag. Syst.p. 76. 
 
 Green, yellowish, brick-red, or scarlet, cells 8 to 10 or 20 
 times as long as broad, witb 20 to 30 chloropbyllose rings in 
 each cell; spores at length densely seriate, rarely disposed 
 irregularly, at first green, afterwards olive-brown, and then 
 red. 
 
 Size. Threads -OSG-'O? mm. diam., oospore "OlS-'OSS mm. 
 
 Rabh. Alg. Eur. iii., p. 318. Eabh. Alg. ex. 309, 455, 147. 
 Cohn, in Acad. Berl. 1855, p. 335. Ann. des. Sci. Nat. 4 ser. 
 (1856) v., t. 12-13. Cienkowski, Bot. Zeit. (1855), p. 777. 
 Fresenius Bot. Zeit (1851), p. 241. Braun, Eejuvenescence 
 p. 164,271,281. 
 
 Conferva annulina, Roth. Cat. iii., p. 7. 
 
 In quarries, pits, or inundated fields. 
 
 Cohn has remarked that whereas most confervoid Algae vegetate by 
 repeated subdivision of the terminal cell, being at some time or other 
 attached by the base, the present has both extremities alike, and 
 neither of them rooting, moreover the vegetation is carried on by 
 sub-division of the central cells, so that the terminal cells remain the 
 oldest. 
 
 Plate Lll. fig. 1. Portion of filament of SrpTiaroplea, wnnulina, -mSa. 
 the green oytioplasm in rings X 400. Fig. 2, cells showing the forma- 
 tion of spermatozoids X 400 with escaped spermatozoids i below. Fig. 
 3, spores having acquired a globose form being fertilized by sperma- 
 tozoids. Fig. 5, spores in an earlier stage. Fig. 8, isolated spore with 
 spermatozoid attached. Fig. 6, mature spores, having acquired an 
 orange colour and stellate outline, the primary membrane is detached 
 X 400. Fig. 7, cells showing arrangement of mature spores X 300. 
 Fig. 4, resting spore in various stages ; a, mature ; h, divided into 2 ; c 
 and d, further subdivided. Fig. 9, zoogonidia X 400. Fig. 10, germina- 
 tion of zoogonidia X 400. All except Fig. 7 after Cohn, 
 
CONFEEVACE^. 135 
 
 Family III. OONFERVAOB^. 
 
 Threads articulate, either simple or branched, vegetation 
 terminal, unlimited. Articulations more or less elongated, 
 rarely abbreviated, now and then shorter than the diameter, 
 cylindrical, rarely swollen. Cell membrane sometimes mani- 
 festly lamellose. Chlorophyllose mass granulate, containing 
 starch granules, effused, parietal, or sometimes contracted in the 
 centre of the cell. 
 
 Vegetation by the repeated division of the primordial utricle 
 in one direction. 
 
 Propagation by zoogonidia. 
 
 Genus 58. BUCROSFORA. Thur. (1851.) 
 
 Articulate thread simple. Chlorophyllose mass at first 
 parietal, afterwards contracted in the centre. All articulations 
 fertile. 
 
 Propagation by zoogonidia. Zoogonidia arising from a 
 simultaneous division of the cell contents, small, numerous, 
 ovate-elliptical, cuspidate and colourless at one end, usually 
 furnished with two, rarely 3 to 4, cilia, escaping by rupture of 
 the cell. 
 
 niiczospoxa fugacissima. (^Ag. Syst. p 43.) 
 
 Pale green, or yellowish green, articulations before division 
 4 to 5 times as long as their diameter, after division about 2 to 
 2^ times as long, not constricted at the joints. 
 
 Size. Cells -OOSS-'Ol mm. diam. 
 
 Eabh. Alg. Eur. iii., 321. 
 
 Conferva fugacissima, Grev. PI. Ed. 317, Gray Arr. i., 310. 
 Kirsch. Alg. Schl. p. 80. 
 
 In ditches. 
 
 Plate LIII. fig. 1. Portions of threads of M. fugacissima X 300 
 diam. 
 
 IHici-ospoira vulgaxis. Salh. Alg. JHur. ui., 321. 
 
 Bright green, articulations 2 to 3J times as long as the 
 diameter. 
 
 Size. Threads '012 mm. diameter. 
 Conferva bombycina iiusqualis, Kiitz. Tab. iii., t. 44, f. 3. 
 Miciospora bombycina, Thuret. Rech. p, 12. 
 Conferva vulgaris, Kirsch. Alg. Schl. p. 79. 
 
 In ditches and pools. 
 
 JPlate LIII. Jig 2. Portions of tlireads of M. vulgaris X 300 diam. 
 
 W 
 
136 SIPHOPHYCE^. 
 
 Miczospoza floccosa. {Ag.) Thuret. Reek. t. 17, /. 4-7. 
 
 Articulations before division about twice as long as the 
 diameter, after division about equal, or a little shorter, slightly 
 constricted at the joints. 
 
 Size. Threads -OlS-'Ol? mm. diam. (according to Kirschner 
 •0075 --01 mm. diam.). 
 
 Rabh. Alg. Eur. iii., 321. Thuret. Ann. Sci. Nat. 1850, t. 
 17, f. 4-5. 
 
 Conferva floccosa, Ag. Sysi. p. 89. Kutz. Tab. iii., t. 43. f. 
 3. Eng. FI. v., 351. Eng. Bot. ii., t. 2474. Harv. Man. 126. 
 Mack. Hib. 224. Gray Arr. i., 310. Kirsch. Alg. Schl. p. 79. 
 
 Lyngbya floccosa, Hass. Alg. 223, t. 60, f. 1-2. Jenner, Tunb. 
 "Wells, 188. 
 
 Conferva fagacissima, Dill. Conf. Supp. t. B. 
 
 In stagnant water. 
 
 Plate LIIl. fig. 3. a, 5, portions of threads X 300 ; c, cells divided 
 across for the escape of zoogonidia X 300 ; d, zoogonidia. 
 
 Geitos 59. CONFEKTA. (JAnn.) Utik. (1820.) 
 
 Articulate threads simple, articulations cylindrical. Ohloro- 
 phyllose mass homogeneous or granulate, including starch 
 granules. 
 
 Vegetation by division in one direction. 
 
 Propagation unknown, (? by resting-spores which subse- 
 quently produce zoogonidia). 
 
 Beoently Wille has declared his belief in the universality of resting- 
 spores in the whole genus Conferva* although it is hardly clear what 
 is his conception of the limits of the genus. In a new species which he 
 has described under the name of Conferva, WittroeHi, he gives detailed 
 account of spore formation, which it is presumed may be accepted as a 
 type of what usually takes place. 
 
 " The chlorophyllaceous contents contract, and become rounded. The 
 colouring matter collects principally in the ends of the cells, so that the 
 substance in the middle appears almost colourless ; but after the con- 
 traction of the cell contents the chlorophyllaceous portions of the 
 protoplasm draw neai'er together, until at last they coalesce and form a 
 round or elliptical body within the mother cell ; they then begin to 
 surround themselves with a membrane, which later consists of two 
 distinct layers. The spores are generally set free by the filaments 
 resolving themselves into H shaped cells (in which the cell wall of each 
 cell has a transverse fissure in the middle of the transverse walls) ; the 
 spores then fall out. Sometimes they escape by the cell walls becoming 
 converted into mucilage, their layers becoming gradually indistinguish- 
 able. On first germinating, the size of the spores increases, as the 
 result of which the outer membrane bursts. The outer membrane 
 consists of two pieces with pointed ends, one being much larger than the 
 
 » Ofrarsigt af Kon. Vetensk Akad Forhandl. xxxviii (1881). " Journal of Eoyal 
 Uicroscopical Society," Dec, 1882, p. 836. 
 
OONFEEYACE^. 137 
 
 other, and covering it like the lid of a box. Afterwai-ds, through the 
 expansion of the inner membrane, the smaller piece of the outer mem- 
 brane gives way, and the inner membrane grows through the aperture 
 thus formed in the form of '•■ tube. The development was not followed 
 further, but the writer considers it probable that zoospores are first 
 formed from the resting spores." 
 
 In Conferva iomiycina, var. minor, either single cells swell up into a 
 barrel shape, or here and there the contiguous ends of two neighbouring 
 cells assume a club-like form. It is here that the largest part of the 
 Chlorophyllaoeous protoplasm accumulates, and after this the swollen 
 end is separated by a transverse wall from the longer narrow part of the 
 mother-cell. The wall of the swollen part thickens later. The author 
 considers these cells to be resting-spores, although he was not able to 
 observe their germination. Conferva Vombycina var. genuina has similar 
 resting-spores. 
 
 Three modes of formation of resting-spores of Confervacem have been 
 observed — (1) by rejuvenescence, and the formation of a new membrane 
 round the contracting contents ; (2) by the thickening of the membrane 
 of the mother-cell ; (3) by separation of a portion of the cell substance 
 to a swollen part of the mother-cell, and the thickening of the membrane 
 of this portion, 
 
 Confexva fontinalis. Berlt. Glean, t. 14, /. 1. 
 
 Bright green, attached ; articulations 6 to 10 times as long 
 as the diameter, slightly swollen, a little constricted at the 
 joints, starch granules single, scattered or seriate, cell-membrane 
 rather thick, homogeneous, when heated with sulphuric acid 
 swelling and distinctly lamellose. 
 
 Size. Threads ■016-'018 ram. diam. 
 
 Kiitz. Tab.'iii., t. 45, f. 4. Eabh. Alg. Eur. iii., 323. Kirsch. 
 Alg. Schl. p. 78. 
 
 Attached to grass, &c., in ditches. 
 
 " It covers rushes, grass, &o., with a short downy green coat, which ia 
 very conspicuous in spring and summer." — Berkeley. 
 
 Plate Lin. fig. 6. Threads of C. fontinalis X 150. Fig. 7, por- 
 tions of thi'eads X 400. 
 
 Conferva teneziima. Kntts. Tab. III., i. 42, /. 1. 
 
 Usually pale green, articulations 1^-3 times as long as the 
 diameter. 
 
 Size. Threads •0035--004 mm. diam. (-OOS-'OOS mm. 
 Kirschner) . 
 
 Eabh. Alg. Eur. iii., 322. Kirsch. Alg. Schl. p. 78. 
 
 In fresh water, often mixed with other Algse. 
 Plate LIU., fig, 5. Portions of threads of C. tenerrima X 400. 
 
 Confezva bombycina. Ag. Syst. p. 83. 
 
 Yellowish green or green, soft, silky ; articulations oblong- 
 cylindrical, slightly constricted at the joints, before division 
 three times as long as the diameter, collapsing alternately when 
 dry. 
 
138 SIPHOPHTCE^. 
 
 Size. Threads -006 --012 mm. diam. 
 
 Eabh. Alg. Eur. iii., 323. Kutz. Tab. iii., t. 44, f. 1, 2. 
 Eiig. Fl. v., p. 351. Eng. Bot. ii., p. 159. Harv. Man. 126. 
 Mack. Hib. 224. Kirssch. Alg. Schl. p. 79. 
 
 Confen-a sordida, Dillw. Conf., t. 60. Johnst. Fl. Berw. ii., 
 254. Eng. Bot. i., t. 2303. Grev. Fl. Ed. 317. Gray Arr. 
 i., 310. 
 
 Vesiculifera bonibycina, Jenner Fl. Tunb. Wells, 186. 
 
 In ditches, pools, &c., common. 
 Plate Llll. jig. 4. Portions of threads of C. bonibycina X 400. 
 
 Genis 60. CHJETOiaORPRA. KuU. (1845.) 
 Articulate thread simple, nearly equally thick, fixed by a 
 discoid, or root-like divided base, lower articulations always 
 short, before division equal, or half as long again as the diameter, 
 after division shorter than the diameter, upper articulations more 
 or less elongated. Cell-membrane thick, firm, sub-cartilagi- 
 nous, manifestly lamellose. Cell contents green, becoming by 
 age parietal, continuous, finely granulate, containing a few 
 starch granules. 
 
 Propagation by zoogonidia. 
 
 Chiefly marine, a few in brackish water. 
 
 The lamination of the cell walls in this genns, and in Cladophora, 
 appeared to Brann to present some analogy to the rings in vascnlar 
 stems. He says, " The great number of layers which may be distin- 
 gnished by suitable treatment in the cell membrane, even of plants of 
 short life {CladopJiora, Botfydium, &c.), is not opposed to the assump- 
 tion that they are diurnal layers, and it is imaginable, under this 
 hypothesis, that bright and dull days, as well as the age of the cell, and 
 other circumstances, may effect important modifications in reference to 
 the formation of distinguishable layers." 
 
 Chaetomoipha litorea. (Barv.) 
 
 Eigid, green, crispate ; articulations before division one and 
 a-half times as long as the diameter, here and there swollen in 
 pairs and discoloured. 
 
 Size. Threads '16 mm. diam. 
 
 Eabh. Alg. Eur. iii., 327. 
 
 Conferva litorea, Harv. Man. p. 208. Phyc. Britt., t. 333. 
 
 Conferva linum, Harv. in Eng. Fl. v., 352. Wyatt, Alg. 
 Danm., No. 220. 
 
 In salt water ditches, and estuaries. 
 
 "Filaments 3-4 inches long or more, loosely bundled together in 
 prostrate or floating strata of considerable extent, and of a pale green 
 colour, becoming darker and duller as the season advances. Each fila- 
 ment is irregularly curled and twisted, and sometimes angularly bent. 
 The articulations ai'e cylindrical, filled with a pale green watery endo- 
 
COifFBRVACBJi!. 139 
 
 olirome, and about once and a-half aa long as broad, and here and there, 
 at irregulai intervals, two proximate articulations, longer and broader 
 than the rest, form together a spindle-shaped swelling, in which a dark- 
 coloured endochrome collects, the mass being darkest and densest where 
 the two cells touch each other. This looks like the commencement of 
 fructification, but I am unable to say whether a sporangium is ultimately 
 formed. These dark-coloured double cells are frequently so numerous 
 that they give the filaments, when examined with a pocket lens, a varie- 
 gated appearance. Substance membranaceous, and in drying the plant 
 scarcely adheres to paper." — Harvey, 
 
 Plate LIY. fig. \. Portion of thread of Choetomorpha litorea X 100 
 diam. 
 
 Cheetomoirpha, linum. (Eoth.) Kutz. Tab. ill., t. 55, /. 3. 
 
 Rather rigid, dark green, or now and then yellowish green 
 and less rigid, lower articulations equal or almost eqnal in 
 length to their diameter, npper articulations, before division, 
 two or three times as long as the diameter, or even four times, 
 here and there swollen. Cell-membrane of the lower articula- 
 tions thick, distinctly lamellose, the upper ones thinner and 
 indistinctly lamellose, contracted at the joints. 
 
 Size. Threads '25 mm. thick. 
 
 Eabh. Alg. Eur. iii., 327. Harv. Phyc. Britt., t. 150, f. a. 
 
 Conferva linum, Ag. Syst. 97. Eng. Bot. ii., t. 2363. 
 
 Conferva capillaris, Huds. Fl. Ang., p. 598. Lightf. Fl. 
 Scot. 988. Dillw. Conf., t. 9. 
 
 Conferva crassa, Eng. Fl. v., 252. Mack. Fl. Heb. 225. 
 
 In brackish and salt water. 
 
 " Filaments from a few inches to several feet in length, twice as thick 
 as a hog's bristle, very much curled, rigid, crisp, and brittle, soon becom- 
 ing flaccid if exposed to the air ; lying in thick but not dense bundles, 
 of considerable length, disposed in strata, one above the other. Articu- 
 lations about as long as broad, filled with granular fluid, which in some 
 joints is more dense than in others. Eventually the joints divide in the 
 centre by a transverse line, and the mass separates, a new diaphragm is 
 then gradually formed, and flnally a new joint. This species varies 
 much in colour, being sometimes of a pale, at other times a dark green, 
 and is very often mottled with dark and light green. Substance rigid- 
 membraneous, scarcely adhering to paper in drying." — Ha/i'vey. 
 
 Plate LIY. fig. 2. Portion of sterile thread of ChcetomorpTia linum, 
 X 100. Fig. 3, portion of fertile thread with zoogonidia X 100. Fig. 4, 
 Zoogonidia X 300. 
 
 Chaetomorpha sutozia. {Berk) 
 
 Dark green, crispate, rather rigid, interwoven in lax tufts, 
 articulations one and a-half times as long as broad, after 
 division shorter than the diameter, cell-membrane thick, dis- 
 tinctly lamellose. 
 
 Size. Threads ■01-'012 mm. diam. 
 
 Conjerva sutoria, Berk. Glean., t. 14, f. 3. Harv. Man. 
 128. Phyc. Britt., 1. 150, f. b. 
 
 In brackish ditches, estuaries, and salt water. 
 
140 SIPHOPHYCE^. 
 
 " Filaments several inctes to a foot or more in length, as thick as 
 hog's bristle, variously carved and twisted, forming extensive, loosely 
 packed bondles or strata which iill the pools in which they grow, ^rfci- 
 cnlations once and a-half as long as broad, filled with a dark green fluid, 
 at length separating by a transverse medial line into two portions, which 
 eventnally become separate joints. Colour dark green, not variegated. 
 Substance rigid, not adhering to paper in drying." — Harvey. 
 
 Plate LIV. fig. 5. Portion of base of thread of Chastomorpha 
 tvtoHa X 100. 
 
 Chaetomoipha implexa. (DeU.) KuU. Tab. in., t. 51, /. 3. 
 
 Pale or deep yellowish green, crispate, interwoven in lax 
 tofts, rather rigid, sometimes mucous, articulations before 
 division twice as long as the diameter ; cell-membrane rather 
 thick, indistinctly lamellose, after application of concentrated 
 sulphuric acid at first homogeneous, but after four hours' action 
 manifestly striate-lamellose. 
 
 Size. Threads, ■04--06 mm. diam. 
 
 Eabh. Alg. Eur. iii., 329. 
 
 Confei-va implexa, Dillw. Conf., t. b. Ag. Syst. p. 91. 
 
 Conferva sutoria, Crouan, Fl. Fin. 
 
 In brackish and salt water. 
 
 " Filaments forming densely interwoven strata, or tnfts among the 
 branches of other Algse. Joints even in the same thread varying from 
 a little shorter than their breadth to aboat once and a-half as long. 
 Colour a dark grass green." — Harvey,'^ 
 
 Mate Liy. fig. 6. Portions of threads of ChcBtomorplia implexa X 
 200. 
 
 Genus 61. RHIZOCI.ONIV]!a. Kittz. (1843.) 
 Articulate thread the same as in Conferva, but distinctly 
 contorted, and forming by prolification of the cells short root- 
 like processes. 
 
 Propagation unknown. 
 
 Khizocloninm Caspaiyi. Harv. Phy. Britt, t. 354, 6. 
 
 Filaments elongated, slender, decumbent, pale yellow green, 
 stratified, interwoven, curved here and there, and angularly bent, 
 at the angles emitting short root-like branches, which some- 
 times lengthen, and are filled with endochrome ; articulations 
 2 to 6 times longer than broad, with narrow dissepiments and 
 granular endochrome. 
 
 Size. Threads •018--025 mm. 
 
 Eabh. Alg. Eur. iii., 330. 
 
 In brackish and salt water. 
 
 " Forming a thin web of a bright green colour and considerable extent. 
 Filaments elongate, gracefully curved rather than twisted, interwoven, 
 here and there angularly bent. At the angle issues a root-like process. 
 
CONFBRVAOB^. 141 
 
 which sometimoB consists of but a few empty cells, at other times 
 lengthens out into a branch. Cells in the same fleece very various, and 
 even in the same filament at different ages ; the full-grown cell seems to 
 be fully six times as long as its diameter; but short cells once and 
 a-half to twice as long as broad, which seem to be cells in prodess of 
 development, are commonly mixed with the long cells. All contain a 
 granular endochrome, the grains of very unequal size." — Marvey. 
 
 Plate LIT. Jig. 1. Portions of thread of Bhizoclonium Casparyi 
 X 200 diam. 
 
 Rhizodonium flavicans. Jurg. Alg. 
 
 Threads soft, simple, extremely fine, matted, somewhat 
 crisped, at first uniform pale green, at length distinctly jointed ; 
 articulations once and a-half as long as broad, dotted; 
 interstices pellucid. 
 
 Size. Threads -018 mm. diam. 
 
 Eabh. Alg. Eur. iii., 331. 
 
 Conferva arenicola, Berk. Glean, t. 13, f. 3. Harv. Man. 
 128. Harv. Phyc. Britt., t. 354A. 
 
 At the mouths of rivers, and salt marshes. 
 
 " Creeping on the sandy margin of pools in a salt marsh periodically 
 flooded, forming a thin, soft, delicate, crisped web of a pale yellow green. 
 Threads extremely slender, flexuous, at first self-coloured, with a few 
 scattered dots, then with manifest dissepiments, and finally the granules 
 contract and form a distinctly defined mass of a darker green in the 
 centre, with pellucid interstices. Articulations one and a half time^s as long 
 as broad. When dry the articulations are alternately contracted." — 
 Berkeley. 
 
 Plate LIY. fig. 8. Portions of threads of RTiisoclaminm fiavioans 
 X 200 diam. 
 
 Gexus '62. CLADOPHORA. Kutz. (1843.) 
 
 Articulate thread variously branched, cell-membrane usually 
 thick, lamellose ; cell contents parietal. 
 
 Propagation by zoogonidia, arising from simultaneous and 
 multipartite division of the cell contents, moving actively 
 ■within the mother-cell, afterwards escaping by a lateral or 
 terminal opening, furnished with 2 or 4 vibratile cilia, after- 
 wards germinating without fecundation. 
 
 Many species are entirely marine, but some are fresh water. All are 
 disposed to considerable variation, and numerous varieties are named in 
 connection with each of the fresh water species. The following arrange- 
 ment of the species from Eabenhorst's Algae will be useful in their identi- 
 fication : — 
 
 I. Threads collected in tufts, more or less lax or intricate. 
 A. Tufts at first attached, afterwards free swimming, 
 a. Cell contents not spirally disposed, 
 t Fruiting cells not terminal. 
 
 * Cell-membrane even fracta. 
 
 ** Cell-membrane plicato-striate . . crispata. 
 
142 
 
 SIPHOPHYOE^. 
 
 B. Tufts for the whole life attached. 
 
 a. Cell contents disposed in lax spirals. 
 
 t Fruiting cells terminal or subterminal. 
 * Cell-membrane even. 
 0. Branches connate 
 
 at the base .... cwnaUcula/ns, 
 00. Branches not connate 
 
 at the base glomerata. 
 
 ** Cell-membrane plicate .... flwvescens. 
 
 II. Threads radiating from a common centre, aggregated in a more or 
 
 less spongy globe ... osgagropila. 
 
 Cladophoxa fxacta. (StZZw.) Eutz. Sp. Alg., p. 410. 
 
 Branches and branchlets sparse, divaricate, here and there 
 refracted, often secund, the lower laterally inserted. Cell 
 contents of the branches not spirally arranged, cell-membrane 
 now and then very thick. Fructiferous cells not terminal, 
 often in the middle of the branches or at their base. 
 
 SiZB. Threads •! mm. diam. 
 
 Kutz. Tab. iii., t. 50. Eabh. Alg. Eur. iii., 334. Jenner 
 Fl. Tunb. Wells 186. Harv. Man. 134. 
 
 Conferva fracta, Eng. Fl. v. 356. Johns. Fl. Berw. ii., 254. 
 Eng. Bot. i., t. 2838, ii., t. 2492. DUlw. Conf., t. 14. Lyngb, 
 Hydr. Dan. t., 52. Grev. Fl. Ed. 318. Hook. Fl. Scot.ii., 82. 
 Mack Hib. 227. Fl. Devon ii., 52. Gray Arr. i., 304. 
 
 Conferva vagahunda, Huds. Fl. Ang. ii., 601. Lightf. Fl. 
 Scot. 990. • With Arr. iv., 139. 
 
 Conferva marina trichoides, lancB instar expansa, Ray. Syn, 
 60. Dillen, Muse. 30, t. 5, f. 32. 
 
 Cladophora crispata, Hass. Alg. 216. 
 
 In fresh and brackish water. 
 
 " At first forming loose tufts, which frequently become detached, and 
 the plant is more commonly found constituting floating strata, many 
 tufts entangled together in each floating mass. Filaments capillary 
 from six to eight or ten inches long, much, but very irregularly branched, 
 the branches distant, spreading at wide angles, or much divaricated, 
 either dichotomous or alternate, the lesser branches repeatedly forked, 
 with wide axils, and the ramuli which are few and very patent, com- 
 monly secund, sometimes alternate. Articulations three or four times 
 as long as broad, rarely six times as long, those of the upper branches 
 pretty uniformly thrice as long as their diameter, at first cylindrical, 
 then becoming pyriform, and when mature elliptical, when the branches 
 resemble strings of dark green beads. Dissepiments finally much con- 
 tracted. Colour at first a pleasant grass green, becoming darker and 
 duller as the plant advances in age. The endochrome is at first fluid, 
 but in the full grown articulations (which are in fact changed into 
 sporangia) it becomes distinctly granular, very dense, and of a dark 
 colour. In drying the plant adheres to paper, but not very firmly." — 
 Horsey. 
 
 Plate liV.fig. 1. Upper portion of filament of Cladophora fracta X 
 10 Fig. 2, portion, with fertile cell X 100 diam. 
 
OONFERVAOEiE. 143 
 
 Cladophoza czispata. (_Bath.) Kutx. Tab iv., t. 40, /. 1. 
 
 Less coloured than the preceding, now and then dark green, 
 sometimes colourless ; branches and branchlets remote, some- 
 times secund, insertion (at least of the lower branches) apical, 
 articulations collapsing, cell contents (at least of the upper 
 branches) disposed in a lax spiral. Cell-membrane delicately 
 plicate-striate. * 
 
 Size. Primary branches '022 mm. thick, ultimate branches 
 less than half that diameter, main thread '12 mm. diatn. 
 
 Eabh. Alg. Eur. iii., 337. 
 
 Conferva crispata, Dillw. Conf. t. 93. Eng. Fl. v., 356. 
 Eng. Bot. i., t. 2350. Hary. Man. 133. Gray Arr. i., 304. 
 Eng. Bot. ii., t. 2420. 
 
 In pools. 
 
 "Filaments about a foot long, or more, densely entangled, rather 
 tough, destitute of gloss, curled and crisped, especially when old. 
 Articulations 4 or 5 times as long as broad ; by drying they become 
 elliptical and compressed alternately." 
 
 Plate LV. fig. 3. Upper portion of filament of Cladophora crispata 
 X 10. Fig. i, small portion of sterile thread X 100 diam. 
 
 Cladophora glomexata. (Linn.) Kutz. Tab. Phye. ly. 
 
 Branches in the upper part of the primary thread, and 
 branchlets of the second and third order, usually fasciculate or 
 penicellate. The cell contents of the larger cells applied in a 
 net-like or somewhat spiral manner to the walls. Fructiferous 
 cells always terminal, with the lower cells sterile. 
 
 Size. Primary and secondary branches to '06 mm. diam. 
 3 to 6 times as long. 
 
 Kabh. Alg. Eur. iii., 339. Jenner Fl. Tunb. "Wells 186. 
 
 Conferva glomerata, Linn. Eng. Fl. y., 306. Lightf Fl. Scot. 
 993. Dillw. Conf., t. 13. Huds. Fl. Ang. ii., 602. Eng. 
 Bot. i., t. 2192, ii., t. 2494. Hary. Man. 134. Part. Mid. 
 Fl. ii,,6I0. Johnst. Fl. Berw. ii., 255. Grey. Fl. Ed. 318. 
 Hook. Fl. Scot, ii., 82. Sibth. Ox. 837. Abbot. Fl. Bedf. 
 375. With Arr. iy., 140. Gray Arr. i., 306. Hass. Alg, 
 213, t. 56,57, f. 1-2. 
 
 Conferva fontinalis ramosissima glomeratini congesta, Ray Syn. 
 59. Dillen.Muso. 28, t. 5,f. 31, A. B. 
 
 Microspora glomerata, Hass. Ann. Nat. Hist. xi. 
 
 In clear streams and riyulets, usually attached to stones. 
 
 "The whole plant is of a bright, shining green, yery smooth, but not at 
 all yisoid or gelatinous to the touch. The principal stems are several 
 inches long, sending out numerous capillary branches, which are variously 
 subdivided, and terminate ultimately in ranges of little short ramuli all 
 
 X 
 
lu 
 
 SIPHOl'HYCEJS. 
 
 directed one way, which gives the plant a peculiar elastered or tuft- 
 like aspect. Articulations at least five times longer than they are broad." 
 —Eng. Bot. 
 
 Plate LVI. fig. 1. Portion of apes of thread slightly enlarged. Fig. 
 2, portion of branch X 100. Fig. 3, tip of branch with zoogonidia X 200 
 diam. Fig. i, zoogonidia X 320. 
 
 eiadophora flavescens. Ag. Syst. p. 112. 
 
 Pale yellowish, six inches long, very much branched, fascicu- 
 late in a plumose manner, branches patent, ultimate branchlets 
 often rather clavate, patent or incurved, cell-membrane often 
 distinctly plicate, cell contents distributed in a reticulate manner. 
 
 Size. Diameter of branches •07--08 mm., 6-12 times as long. 
 
 eiadophora glomerata, -^.flavescens, Eabh. Alg. Eur. iii., 342. 
 
 eiadophora flavida, Kutz. Sp. Alg., p. 402. 
 
 Conferva flavescens, Eng. Fl. v., p. 356. Dillw. Conf. Supp., 
 t. E. Harv. Man. 133. Eng. Bot. i., t. 2088 ; ii., t. 2493 ; 
 Wyatt Alg. Danm., No. 224. Mack. Hib. 227. Gray Arr. 
 i., 304. 
 
 Conferva pinnatula, Dillw. Conf., t. 95. 
 
 In ditches or pools of brackish or fresh water. 
 
 " This species grows in continuous tufts, which, as they rise to the sur- 
 face, form extensive floating strata covering the pool. Filaments slender, 
 capillary, tangled together, irregularly branched ; the main thread some- 
 what dichotomous, with widely spreading axils, and often bent in an 
 angular manner first to one side then to the other ; the lateral branches 
 alternately divided, patent, with a few distant, scattered, alternate, or 
 secund ramuli. Articulations cylindrical, many times longer than broad, 
 filled with a pale, granular endochrome. Colour when young, a yellowish 
 green, becoming yellower in age, and at last almost golden. When dry 
 it has a silky appearance, and fades in the herbarium to a yellowish 
 white. Substance soft, membranous, but not strongly adhering to 
 paper." — Harvey. 
 
 Besides its pale green colour it is readily distinguished from C. fracta 
 by the much longer articulations, and their less granular contents. 
 
 Plate LV. Jiff. 5. Upper portion of filament of Cladophoi'a flaves- 
 cens X 10. Fig. 6, portion of filament with fertile terminal cell X 100. 
 Fig, 7, apex of terminal cells, with zoogonidia escaping x 200. 
 
 eiadophora canaliculaiis. (JiotTi.) Eni~. Sp. 409. 
 
 Dichotomously or trichotomously branched, branches connate 
 at the base, often fasciculately branched abore as in C. glome- 
 rata. Fructifeions cells terminal. Cell- membrane often thick, 
 now and tben swollen. Cell contents arranged in very lax spirals. 
 
 Size. Lower branches •08-"12 mm., 4-8 times as long. 
 
 Eabh. Alg Eur. iii., 342. 
 
 Alga in tubules aquam fontanam deducentihus, Dill. Muse, 
 t. 4, f. 15. 
 
 Conferva canalicularis, Sibth. Ox., 336. Hall Br. Fl., 331. 
 Abbot Fl. Bedf. 274. With. Arr. iv., 129. Eelh. Cant. 
 443. Huds. Fl. Angl. 593. Purton Midi. Fl. ii., 610. 
 
CONFEUVACB.E. 145 
 
 In ditches, pools, and other standing water. 
 
 Articulations four to eight times as long as their diameter, usually 
 bright green. 
 
 Flate LVI. Jig. 5. Part of branch of 0. cmaUcularis X 100 diam. 
 
 Cladophoxa aegagxopila. (Linn.) Kutz. Tab. iii. 
 
 Dark green, threads rigid, very much branched, radiating 
 from a common centre, at length agglomerated into a very 
 dense, spongy globe. Eamuli erect, often quite obtuse, articula- 
 tions sometimes incrassated upwards, cell contents not arranged 
 in spirals, cell-membrane now and then thickened. 
 
 Size. Branches •04--07 diam, 2-4 or even 12 times as long. 
 
 Eabh. Alg. Eur. iii., 343. 
 
 Conjerva cegagropila, Linn. Dillw. Conf., t. 87. Purt. 
 Mid. Fl. iii., p. 175. Eng. Bot. ii., 1377 ; ii., 2496. Harv. 
 Man. 134. Eng. PI. v., 357. Huds. Fl. Ang. ii., 604. Mack. 
 Hib. 228. Hull Br. Fl. 332. Hook. Fl. Scot, ii., 82. 
 With. Arr. iv., 141. 
 
 Conferva globosa, Phil. Trans. Eoy. Soc. xli., 498. 
 
 Conferva cegagropilaris, Gray Arr. i., 308. 
 
 Cladophora glomerata, Hass. Alg., p. 213 in part. 
 
 var. Bxoivnii (Dillw.). 
 
 Eabh. Alg. Eur. iii., 345. 
 
 Conferva Brownii, Dillw. Conf. Syn., t. d. Harv. Man. 134. 
 Eng. Fl. v., 356. Wyatt Alg. Dan., No. 225. Mack. Fl. Hib. 
 228. Eng. Bot. 2879. 
 
 " This singular vegetable production is a native of Alpine lakes in many 
 parts of Europe, often lying in great abundance at the bottom of the 
 water, and occasionally only rising and floating on the surface. It has 
 been found in the lakes of the north of England, Wales, Scotland, and 
 the district of Connemara in Ireland, but is generally esteemed rare. In 
 size it varies from that of a small pea to three or four inches in dia- 
 meter, and its form is always nearly spherical. Internally the larger 
 specimens are hollow, without any nucleus, and when examined their 
 substance is found to consist of innumerable green, pellucid, repeatedly 
 branched filaments, firmly entangled together. The vesicles, when the 
 plant is recently taken from the water, are turgid with fluid, and nearly 
 cylindrical, being slightly swollen towards the apex, where the granular 
 matter of the endochrome seems chiefly collected as a green opaque 
 mass ; in the terminal vesicle, however, of each branch it assumes often 
 a dark brown hue and more solidity, probably becoming the medium of 
 reproduction, and escaping in the form of sporules. The elasticity of 
 the balls may be estimated by the fact of their having been used as pen- 
 wipers in the north of England. — Ung. Bot. 167. 
 
 Plate LVI. fig. 6. Threads of 0. CBgagropila, nat. size. Fig. 7, portion 
 of upper branch X 100 diam. 
 
1J:6 siphopSycejs. 
 
 Family IY. PITH0PH0RA.GE^. 
 
 Chloropliylliferons Cladophora-like Fresh-water Alg», con- 
 sisting of cells formed by bipartition of the terminal cell, the 
 thallus having two distinct parts — (1) the cauloid part, 
 developed from the germinated spore upwards, propagative, and 
 almost always branched, the branches placed a little space 
 below the top of their supporting cells ; (2) the rhizoid part 
 developed from the germinated spore downwards, almost always 
 sterile and branchless, commonly unicellular. Spores neutral, 
 quiescent (agamo-hypnospores), generally cask-shaped, single, 
 formed by division into two of the cauloid cells, of the chloro- 
 phyll filled, and commonly widened upper parts of these cells ; 
 in germinating, as a rule, dividing into two cells, the one 
 giving rise to the cauloid and the other to the rhizoid part 
 of the thallus. — Wittrock, Monograph of the Pithophoracece, 
 p. 46. 
 
 For full details of this Family, consult Prof. V. B. Wittrock " On the 
 Development and Systematic Arrangement of the Pithophoraceje " (pub- 
 lished in English). Upsal, 1877. 
 
 Genus 63. PITHOPHORA. WiUr. (1877.) 
 Character the same as that of the family given above. 
 
 The formation of spores is effected in the following manner : — The 
 upper part, ^-^ of the mother cell of the spore, is somewhat widened. 
 The ehlorophyll«coloured protoplasm in the lower, not widened, part of 
 the cell then passes little by little into the upper and widened part, till it 
 is quite filled with chlorophyll-coloured protoplasm. A transversal cell 
 wall is then little by little formed just below the point where the 
 widened part of the cell commences. In this manner are formed one 
 lower cell containing but little protoplasm, almost devoid of chlorophyll, 
 the so-called subspoi-al cell, and one upper cell, rich in chlorophyll and 
 reproductive, the spore. Its shape is, as a rule, cask-like or cylindri- 
 cally cask-like. When the membrane of the spore has attained a not 
 inconsiderable increase in thickness the spore reposes some time before 
 germinating, and consequently belongs to the class of spores which is 
 called hypnospores With regard to its origin, it may be called an 
 agamo-spore, as being formed neutrally without any fecundation. 
 Formation of spores may take place in all the cells of the cauloid, in the 
 terminal as well as in the inclosed. As a rule it begins in the youngest, 
 i.e., the terminal cells ; afterwards proceeding downwards, or, in other 
 words, basipetally, in the principal tilaraent as well as in the branches. 
 It is these spores which give origin by their germination to the course of 
 development already described. In this manner you will see one neutral 
 generation, forming hypnospores, follow upon another, in an uninter- 
 rupted series, without any metagenesis. 
 
PITHOPHORACB^. 147 
 
 The reprodnotion of individuals may, however, be effected also in another 
 way than by the formation of spores. Besides the specimens which 
 form spores, there are others which never do so. These, which are dis- 
 tinguished by a richer ramification, transform part of their cells into so- 
 called " prolific cells.*' A common vegetative cell grows richer in 
 chlorophyll coloured protoplasm and starch, and is thus made fit to form 
 a new individual. This the prolific cells do, when they have been made 
 free, by the destruction of the mother specimen, by forming a new speci- 
 men laterally near their top, in the same manner as a branch — and later 
 a system of branches — is formed by a cell in the fertile specimens. That 
 the specimens originated by prolific cells have the power of forming 
 spores is certain, as well as that specimens forming prolific cells may 
 have been originated by spores. I do not know with certainty whether 
 specimens forming prolific cells may have been originated by prolific 
 cells themselves, but it seems to me in no wise improbable. — Witt- 
 rock, 1. 0. 
 
 Fithophora Kewenais. — Wittr. Mon.p. 52. 
 
 Principal filament of tlie cauloid part of the thallus, in fertile 
 specimens, on an average '059 m. thick, with solitary branches 
 of only one degree (rarely of two), spores single, partly enclosed, 
 partly terminal, the enclosed spores cask-shaped, but more 
 elongated, on an average -08 m. thick and -2 m. long, the 
 terminal spores cask-shaped, with the upper end conical and the 
 top somewhat rounded, on an average '088 mm. thick and '219 
 mm. long ; the rhizoid part of the thallus as a rule unicellular. 
 
 Wittr. Mon. Pithoph. t. 1 f. 8, t. 2 f. 1-12 ; t. 3 f. 1-9 ; 
 t. 4 f. 2-11 ; 't. 5 f. 9 10. 
 
 In tank. Water-lily house, Kew Gardens. August. 
 
 This singular plant is thought by Wittrock to have been an importa- 
 tion from Brazil. It has not been seen in its original locality for two or 
 three years. 
 
 Flate L7I. fig. 8. Portion of spore-bearing filament x 20. Fig. 9, 
 portion of principal filament with spore formed at the apex of a short 
 branch, and another in process of formation in the principal filament 
 X 200. Fig. 10, a mature enclosed spore x 200. Fig. 11 , part of cell 
 from rooting portion of a sterile thread x 200. All after Wittrock, 
 
148 
 
 NBMATOPHYOE^. 
 
 Family V. (EDOGONIACE^. 
 
 Moneecious, or dioecious algae. Filaments articulated, either 
 simple (CEdogonium) or branched (Balbochcete). Basal cell 
 obovate-clavate, mostly lohately divided, or ending in a disc. 
 
 Propagation by zoospores, or by oospores after sexual fecunda- 
 tion. The zoospores formed singly in certain cells, broadly oral 
 or globose, transparent at one end, and furnished with a crown 
 of yibratOe cilia. Oogonia single or in a chain (2 to 5) con- 
 tiguous to each other, more or less tumid, with a single oospore 
 in each, becoming reddish brown or yellowish when mature, 
 and then, before germination, dividing into (mostly 4) 
 zoospores. 
 
 Male plants, dwarf (nannandrous) and attached to the female 
 plants, or elongated (macrandrous) and similar to the female 
 filaments (often rather thinner). Spermatozoids produced in 
 abbreviated special cells (spermogonia) . 
 
 Genvs 64. (ESOGONIUBI. Linlc. (1820.) 
 
 Articulated filament simple, at first fixed, afterwards free 
 swimming. Cells marked with transverse stria; at one or other 
 extremity. Terminal cell sometimes elongated and setiform. 
 Either monoecious or dioecious ; when dioecious the male plants 
 either dwarf — produced from short cells of the female plants — 
 or elongated and independent. 
 
 Propagation by asexual zoospores, and by oospores sexually 
 fertilized. 
 
 For details of the stmoture and reprodnotion, conanlt " Braim on 
 Eejnvenescence " (Bay Society, 1853). " Pringsheim Jahrbucher" 
 (1857). " Quarterly Journal of Microscopical Science," vi. new series, 
 18G6, p.l49. DeBary, " .aidogonium nnd Bnlbochaete " (1854). Jnranyi 
 in Pringsheim " Jahrbncher " (1873). Carter, in " Annals of Natural 
 Historr," 3 ser. i, p. 81. Vaupell, " Jagttagelser ov. hefrugt. CEdogo- 
 nium""(1859). Wood, " Fresh Water Algse of the United States " (1872). 
 Wittrock, " Prodromns Monographise CEdogonieamm " (1874'. 
 
 The sterile filaments of . (E(?o^o»ium resemble those of Cinferva at a, 
 casual glance, but are soon seen to be distinguished by transverse parallel 
 strise at one or other extremity of many of the cells. These striae are 
 indications of the mode of cell increase (PI. LTII, fig. 5) which takes 
 place in the following manner: — When a cell has reached maturity, and 
 is about to divide, a little circular line is seen near its upper -end. 
 Gradually the line widens, and it is seen that the wall of the mother 
 cell has divided all round, and the cell above is slowly raised by the 
 growth of the daughter cell, arising, as it were, out of the apex of its 
 J arent cell, and carrying upwards the first streak or cap left by the 
 
CEDOOONIAOE^. 149 
 
 breaking away of the wall of the mother cell. In this manner the new 
 cell soon attains a length equal to the one from whence it sprang (the 
 Buocessive stages shown on Plate LTII, figs. 1 to i). "When the young 
 cell has matured it becomes in turn a mother cell, the splitting round is 
 repeated, a second streak or cap is carried upwards, and thus as many as 
 four, five, or six successive cells are formed, as indicated by the four, 
 five, or six striae or caps which may be counted at the apex of a cell. The 
 number of caps corresponding to the number of cells produced in this 
 manner*oonsecutively immediately beneath the caps. 
 
 Asexual reproduction takes place by the formation of a single zoospore 
 in one of the cells of the filament (Plate LTII, fig. 15). It is of a globose 
 or somewhat ovate form, furnished near its apex with vibratile cilia (fig. 
 14). When mature it escapes by rupture or fissure of the mother cell, 
 moves about for awhile, then becomes attached by the ciliated end, and 
 ultimately developes into a young plant. 
 
 Sexual reproduction is varied in three ways. In the monoecious species 
 the oogonium is an inflated cell, more or less globose, enclosing a single 
 oospore of similar form. The oogonium is either perforated by a pore, 
 or splits round and opens with a lid or operculum. The same thread 
 bears above or below the oogonium very much shortened cells, in which 
 one or two active spermatozoids are produced. These escape when 
 mature, and fecundate the oospore through the perforation or opening of 
 the oogonium, after which they disappear, and the oospore ripens into a 
 perfect, fertile, resting spore. 
 
 In the dioecious species there are two modes of sexual reproduction. 
 In one group of species the males are dwarf, almost might be called 
 antheridia. The oogonia and oospores are the same as in the monoecious 
 species. In like manner there are also abbreviated cells in some other 
 part of the same thread, but these do not produce spermatozoids, but 
 androspores, small active ciliated bodies, which move about for a time, 
 and then attach themselves either upon or near the oogonia, grow into 
 the form of an inverted flask (figs. 8 to 10), being supported by a more or 
 less elongated stem, and constitute the dwarf male (nannandrous) plants, 
 the cells at the apex of which contain the spermatozoids, the upper cell 
 opening by a lid, or cap, to permit of the escape of its contents, which 
 fertilize the oospore as in the previous method. 
 
 The second group of dioecious species have male filaments, which in 
 all respects resemble the sterile females, except that they are usually a 
 little thinner. The female filaments produce only the oogonia. 
 The male filaments, in certain abbreviated cells, give origin 
 to the spermatozoids, which in due time escape and fertilize the 
 oospores of the female plants. Thus, in the first group, the dwarf males 
 are generated in certain privileged cells of the female plants, whilst in 
 the second group the male and female filaments are from the first dis- 
 tinct. The former are called nannand/rous species, the latter macran- 
 drous. 
 
 The fertilized oospore becomes a resting spore, which ultimately 
 passes through the following stages : — Previous to germination the spore 
 has an egg-shaped figure ; the cell contents are densely crowded, and 
 composed of minute brownish-green granules, closely surrounded by a 
 distinct cell-membrane. Outside this membrane there is found besides 
 quite a distinct cell-membrane. Upon germination there are formed in 
 both membranes slit-like openings, whereupon the cell contents emerge, 
 surrounded by an extremely delicate hyaline covering. The cell contents 
 are composed not of one, but usually of four green masses, each sur- 
 rounded by its cell-membrane. Sometimes also as it appears, abnor- 
 m ally, the masses are two or three in number. The four cells which 
 proceed from germination possess an oval form, and their cell-membrane 
 is hyaline. After the contents of the spore have emerged there remains 
 
150 NEMATOPHTCE^. 
 
 behind the outer membrane, enclosing the inner one. After the four 
 cells have remained some time enclosed in the hyaline covering, this 
 becomes resorbed subsequently, and the four cells lie still and motion- 
 less, but after the course of a short time the cells burst on one end by 
 means of an annular slit, and the apex, separated thereby from the 
 remainder of the cell-membrane, becomes elevated like a lid. Through 
 the circular opening the cell contents now emerge, which at the part 
 turned towards the opening is colourless. This apex moves with 
 vigorous motion backwards and forwards, and after an houi»the cell 
 contents, in the form of a zoospore, leave their place of detention, which 
 we now find to be a doubly-coloured cell-membrane. The little zoospore 
 wheels in a lively manner about with a circling movement, whereby the 
 colourless point becomes directed downwards. Its appearance is like 
 that of an ordinary zoospore, and, like it, possesses an oval form and a 
 lighter apex, furnished with cilia, which during the motion is always 
 directed forwards. After a time the movements become faint, and 
 finally cease. The cilia disappear, and the light end becomes elongated 
 into a root, which sometimes becomes an organ of attachment, quite 
 like that produced in the germination of the ordinary zoospores. The 
 rounded end of the germinating zoospore acquires a little point-like 
 apex. This growth becomes divided by a transverse septum, and a little 
 two-celled Qidogonium has originated. From each spore there are thus 
 derived, in general, four plants. 
 
 Plate LYIl. figs. 1-5. Stages in the formation of new cells — after 
 Pringsheim. Fig. 6, male cells of Bulbocluete crassa, with spermogonia. 
 Fig. 7, zoospore of (Edogonium — after Pringsheim. Figs. 8-10, develop- 
 ment of dwarf males — after De Bary. Fig. 11, spermogonia. Figs. 
 12-13, imgregnation of CEdogonium dliatum — after Pringsheim. Fig. 14, 
 zoospore of CEdogonium rimilare. Fig. 15, zoospore developing in its 
 mother-cell — after Pringsheim. Fig. 16, zoospore of Sulboeheste 
 setigera. Figs. 17-19, segmentation of resting spores of CEdogonium. 
 Fig. 20, oospore escaping from oogonium. Fig. 21, mature oospore of 
 Bulbochtste undergoing division. Fig. 22, four zoospores developed 
 from the same. Fig. 23, sterile cells of CEdogoniv/m Seinschii. All 
 magnified 400 diam. 
 
 The following is an arrangement of British speoies, on the basis of 
 Wittrook's " Monograph " : — 
 
 CBDOGONrUM. 
 
 Sect. 1. Species monoecious. 
 
 A. Oogoma aVwayt dettitvte of median processet. 
 a. Oospores globose or aabglobose. 
 a Oogonia globose or subglobose. 
 (E. Petri, WiUr. 
 CB. oryptosporum, Wittr. 
 CE. curvom, Pringsh. 
 CE. cymatospomm, W. ^ N. 
 CE. minus, Wittr. 
 CB. vemale, Mass. 
 CE. crispum. Hats. 
 CB. Vauoherii, he CI. 
 /3 Oogonia elliptic or egg-shaped, 
 CB. nrbicum, Wittr. 
 h, Oospores ellipsoid or egg-shaped. 
 CE. paladosnm, San. 
 
CBDOQONIACKJS. 151 
 
 B. Oogonia furnished with verticellate meiian processes. 
 u,. Oospores sabglobose. 
 
 CB. Itzigsohnii, Be By. 
 h. Oospores subellipsoid. 
 
 CE. exoisum, Witt?: ^ Lund. 
 
 OS. Aroheriaaum. Cke. (Pringsheiimanum, Archer). 
 
 Sect. 2. Dioecious species. 
 
 Snb-Sect. 1. Species with dwarf males. 
 
 A. Species mith dwarf males vmicellular. 
 
 a. Oogonia furnished with verticellate processes in the 
 middle. 
 
 (E, platygynum, Wittr. 
 h. Oogonia always destitute of median processes. 
 a Oospores globose or subglobose. 
 CB. Rothii, Le 01. 
 CE. Aresohougii, Wittr. 
 CB. pluviale, Nord. 
 CE. undulatum (Breb.). 
 CB. Beinschii, Soy, 
 Oospores subellipsoid. 
 None. 
 
 B. Species iicellular, spermogonia internal, with dwarf males. 
 
 CB. depressum, Prings. 
 
 C. Species with dwarf males bi-multicelhilar, spermogonia external. 
 
 a. Oospores even. 
 
 a Oospores globose or subglobose. 
 CE. flavescens, Kass. 
 CB. Brannii, Kutz. 
 CE. maorandum, Wittr. 
 CB. crassiusculum, Wittr. 
 
 j3 Oospores ellipsoid or egg-shaped. 
 CB. Borisianum, Le, CI. 
 CE. coDcatenatum, Bass. 
 CE. aorosporum, I). By. 
 CB. ciliatnm, Mass. 
 
 i. Oospores echinulate. 
 a Oospores globose. 
 CE. Cleveanum, Wittr. 
 CB. echinospermum, Br. 
 
 fi Ooospores ellipsoid. 
 None. 
 
 Sub-Seot. 2. Species dioecious, with elongated male plants. 
 
 a. Oospores echinulate. 
 
 None. 
 5. Oospores smooth. 
 
 a Oogonia not, or slightly, swollen. 
 CE. oapillare, L. 
 
152 NEMATOPHYCB^. 
 
 /3 Oogonia manifestly tumid. 
 
 aa Oospores globose or snbglobose. 
 
 CE. calcareum, Witti: 
 
 CB. cardiaonm, Bass. 
 
 CB. carbonionm, Wittr. 
 
 CE. Pringsheimii, Oram. 
 
 CE. punotato-striatnm, D. Sy. 
 
 PP Oospores ellipsoid or egg-shaped. 
 
 CE. Boscii, Le 01. 
 CE. tumidulnm, Xutz. 
 CE. Landsboroughii, Hass. 
 V. gemellipamm, Pr, 
 CB. rivnlare, Le CI. 
 
 Sect. 3. Species of which the organs of fructification are imperfectly 
 known. 
 
 u.. Oospores globose or snbglobose. 
 CE. delioatnlnm. Kvtx. 
 CE. tenellnm. Kutz. 
 CE. hezagonum. Hass. 
 CB. Londinense. Wittr, 
 CB. fasciatum. Kutz. 
 CE. capillaceum. Kute. 
 CE. HntchinsisB. Wittr. 
 CB. prinoeps. Sass. 
 
 h. Oospores snbelliptic or oval, 
 CE. longatnm. MJutz. 
 CE. vesicatnm. Lyngb. 
 CB. grande, Kutz. 
 CE. giganteum. Kutz. 
 CE. crassnm. Hass. 
 CE. Bubsetaceum. Kvtz. 
 
 The following of Hassall's species of VesicuHfera hare not been iden- 
 tified :— 
 
 Vesicnlifera oondensata, floss. P. W. Alg. p. 196. 
 „ Ouvieri, ffass. F. W. Alg. p. 198. 
 
 „ Ealfsii, floss. F. W. Alg. p. 199, t. 50, f. 8. 
 
 „ virescens, floss. F. W. Alg. p. 200, t. 50, f. 5. 
 
 „ ovata, floss. F. W. Alg. p. 201, t. 50, f. 6. 
 
 „ dissiliens, floss. F. W. Alg. p. 202, t. 50, f. 7. 
 
 sphffirica, Bags. F. W. Alg. p. 204, t. 53, f. 6. 
 „ inffiqnalis, tfoss. P. W. Alg. p. 205, t. 53, f. 2. 
 
 „ dubia, floss. P. W. Alg. p. 206, t. 53, f. 14. 
 
 „ Mnlleri, Bass. P. W. Alg. p. 207, t. 53, f. 10. 
 
 „ alata, floss. F. W. Alg. p. 208, t. 52, f. 9. 
 
 „ affinis, floss. F. W. Alg. p. 206, t. 53, f. 1. 
 
 Some of Kntzing's species, which are imperfectly described, have been 
 mentioned as British, but we hare no sufficient knowledge of them to 
 warrant their insertion. 
 
CEDOGONIACB^. 153 
 
 Section 1. Moncecious species. 
 
 A. Oogonia always destitute of median processes. 
 
 a. Oospores globose or subglobose. 
 
 (Edogonium Fetxi. Wittr. Mon. Mldog. p. 6. 
 
 Oogonia single, rery rarely binate, pear-shaped globose, open- 
 ing by a pore a little above the middle. Oospores rather 
 depressed globose, almost filling the oogonium ; spermogonia 
 1-2 celled, hypogynous or epigynous ; spermatozoids single (?), 
 terminal cell obtuse. 
 
 Size. Cells •006-*007 mm., 5-7 times as long; oogonia 
 •021--024 mm. x •022--029 mm.; oospore ■020--23 X 
 •017--019 mm. ; cells of spermogonia •0055--006 x ■01--011 
 mm. 
 
 Kirch. Alg. Schles. p. 51, 
 
 Ireland. 
 
 Having carefully measured a great number of the epeoies here re- 
 corded, and found Wittrook's measuremente universally accurate, we 
 have given his dimensions throughout for all the species recorded by him. 
 Unfortunately it is not easy to reduce Rabenhorst's measurements to 
 millemetres, and equally diifioult to reconcile them. 
 
 Plate LXVIII. fig. 1. (Edogoniv/m Petri with oogonia X '400. 
 OEdogonium czyptopozum. Wittr. Dispos. (Ed. p. 19. 
 
 Oogonia single, elliptic, or rather depressed globose, opening 
 by a median pore, almost filling the oogonium, spermogonia 2-7 
 celled, scattered. Spermatozoids single (?). 
 
 Size. Cells •007-'009 mm. 4-6 times as long ; oogonia 
 •024--025 X •026--027 mm. ; oospore •022--023 X •019--021 
 mm. ; cells of spermogonium -OOe-'OOS x ■007-'011 mm. 
 
 var. p. vulgare. Wit1/r. 
 
 Oogonia 2-5, continuous or single, spermogonia 1-4 celled, sub- 
 epigynous or hypogynons, or scattered. 
 
 Size. Cells -OOS-'OOS mm. 3-5 times as long; oogonia 
 •018--025 X •018--026 mm, ; oospore •016--022 x •013--018 
 mm. ; cells of spermogonium •005-'007 X ■009-'012 mm. 
 
 Kirch. Alg. Schles. p. 52. Wittr. Mon. p. 7. 
 
 Britain. 
 
 We have only seen the variety, from the West of England. The type 
 form has not yet been found in Britain. 
 
 Plate LXVIII. fig. 2. (Edogonium cryptoporum. var. vulgwre with 
 oogonia x 'lOO 
 
154 
 
 NEMATOPHYCEiE. 
 
 (Edogoniiun ciimiin. Pnngs. Beitr. p 69, t. 5, /. 3. 
 
 Oogonia 2-7 continuous, or single, depressed globose, opening 
 by a median pore ; oospores depressed globose, filling the 
 oogonium ; spermogonia 3 or many celled, situated in the upper 
 part of the filament ; spermatozoids single, the upper part of 
 the thread arcuate, or spirally twisted. 
 
 Size. Cells ■005-'01 mm. 1^4 times as long ; oogonia 
 •023--025 X •02--024mm.; oospore ■02--023 x •016--019 mm. ; 
 cells of spermogonium •007--009 x -OOy-OOg mm. 
 
 Wittr. Mon. OEdog p. 8. Kirch. Alg. Schles. p. 52. Kabh. 
 Alg. Eur. iii. 350. 
 
 Ireland. 
 
 Plate IiVIII. jig. 3. (Edogoniv/m curvum, with oogoma and spermo- 
 gonia X 400. 
 
 (Edogonium cjrmatospoznm. Wittr. S[ Nord. in Wittr. disp. CEdog. 
 
 p. 121. 
 
 Oogonia single, rarely binate, rather depressedly globose, 
 opening by a pore at the middle, or a little above the middle, 
 nearly filling the oogonium, membrane of the oospore-scrobicu- 
 late (undulated in a transverse section), pits deep and dense; 
 spermogonia 1-4 celled, somewhat epigynous, hypogynous, or 
 scattered ; spermatozoids single. 
 
 Size. Cells ■008--01 mm. 4-7 times as long; oogonia 
 •024--034 X •027--036 mm. ; oospore ■022--031 X •019--027 
 mm. ; cells of sperm. •008--009 x -OOO-'OIS mm. 
 
 Wittr. Mon. CEdog. p. 8. 
 
 Britain. 
 
 Plate LTIII. fig. 4. (Edogonium cymatosporum with oogonia. a 
 oospore vertical view x 400. 
 
 (Edogouium minus. Wittr. Mon. (Edog. p. 9. 
 
 Oogonia single, depressedly globose, manifestly splitting 
 round in the middle, opening by a median pore, oospores de- 
 pressedly globose, nearly filling the oogonium; spermogonia 
 1-10 ceiled, subepigynous, or subhypogynous, or rarely scat- 
 tered ; spermatozoids single ; vegetative cells slightly capitate, 
 membrane of vegetative cells and oogonia figured with dense 
 points spirally disposed. 
 
 Size. Cells -OOQ-'OIS mm. 3-6 times as long; oogonia 
 •034:--046 X •028--042 mm.; oospore •03--042 X •026-036 
 mm. ; cells of sperm. •009--012 x -OOS-'OOSmm. 
 
 CEdog. punctato-striatum DeBary var. minor. Wittr. disp. 
 (Edog. Suec p. 123. Eabh. Alg. Eur. No. 2277. 
 
 Ireland. 
 
 Plate LTIII. fig. h. ffiao^onwm miraits with oogoma x 400. 
 
CED0G0NIACEJ5. 
 
 155 
 
 (Edogonium vexnale. (Hass) Wittr. Man. (Edog.p. 10. 
 
 Oogonia single, obversely egg-shaped or globose, opening 
 with an operculum, fissure narrow, oospores globose, not filling 
 the oogonium, spermogonia bicellular, sub-epigynous. 
 
 Size. Cells -010- 016 mm. by 4^-6 times as long ; oogonia 
 ■339--045 X •045--051 mm. ; oospore •034--038 x •034--039 
 mm. ; sperm, cell •01--012 x •008--009 mm. 
 
 Vesiculifera vernalis Hass. F. W. Alg. p. 434. 
 
 Vesiculifera Candollei Hass. F. W. Alg. p. 208, t. 52, f. 9. 
 Rabh. Alg. Eur. iii. 355. 
 
 England. 
 
 Flate LYIII. fig, 6. (Edogonmm vernale with oogonia and spermo- 
 gonia ^ 400. 
 
 (Edogonium ciispum. (Hass) Wittr. Mon. (Edog.'p. 10. 
 
 Oogonia single, obversely egg-shaped or globose, opening 
 with an operculum, fissure narrow; oospores nearly globose, not 
 filling the oogonium ; spermogonia 2-5 celled, hypogynous, or 
 sub-epigynous ; spermatozoids binate, terminal cell obtuse. 
 
 Size. Cells ■012-'018 mm. 2-4^ times as long; oogonia 
 •037--049 X •042--054 mm. ; oospore •033--046 x •034--046 
 mm. ; sperm, cell •009--014 x •007--012 mm. 
 
 Kirch. Alg. Schles. p. 52. 
 
 Versiculifera crispa, Hass. F. W. Alg. 203, t. 52, f. 8. 
 
 (Edogonium rostellatum, Prings. Beitr. p. 69, t. 5, f. 1 ; 
 Archer Quart. Journ. Micr. Sci., 1867, p. 79 ; Eabh. Alg. Eur. 
 iii, 347. 
 
 CEdogonium pulchelhcm, Braun. Rabh. Alg. Eur. 2095. 
 
 Britain and Ireland. 
 
 " This is one of several monceoious species, but it is also characterized 
 by the oogonium not opening by a pore or aperture formed in its wall, 
 for the admission of the spermatozoids, as is usual in this genus, but by 
 a ciroumsoissile dehiscence. From the cleft so produced an inner mem. 
 brane projects, which seems to be itself perforate."^.ilTO/ier. 
 
 Plate LVIII. fig. T. CEdogonium crispum yvith oogonia x 400. 
 
 {Edogonium Vauchezii. (Ze Olerc.) Braun. Chytr, t. 2, /. 13. 
 
 Oogonia single, obversely egg-shaped, or globose, or nearly 
 globose, opening by a pore above the middle ; oospores globose 
 or nearly globose, not completely filling the oogonium ; spermo- 
 gonia 2-4 celled, sub-epigynous or hypogynous, spermatozoids 
 binate. 
 
 Size. Cells •02--03 mm. l-|-4 times as long; oogonia 
 •04--055 X •045--065mm.; oospore •035--05 x •035--052 mm. ; 
 sperm, cell •017--024 x •006--011 mm. 
 
 z 
 
156 NEMATOPHTCE^. 
 
 Wittr. Mon. CEdog., p. 13. Kirch. Alg. ScHes, p. 52. Eabh. 
 Alg. Eur. iii., 349, in part. 
 
 Prolifera Vaucherii, Le. Clerc sur. Prolif. 474, t. 24, f . 4 ? 
 VesicuHfera Vaucherii, Hassall, t 50, f. 4. 
 
 Britain. 
 
 Plate LVIIl. Jig. 8. CEdogonium Vaucherii, with oogonia and 
 spermogonia x 400. 
 
 (Edogonium uibicam, Wittr. Mon. (Edog. •p. 13. 
 
 Oogonia single, ellipsoid, opening by a pore above the 
 middle, oospores globose, not filling the oogonium, spermogonia 
 usually 2 celled, spermatozoids binate, supporting cells destitute 
 of chlorophyll. 
 
 Size. Cells -016 mm. by 2^, 6 times as long ; oospore 
 •033--045 X ■033--045mm. 
 
 Kirch. Alg. Schles. p. 52. 
 
 (Edogonium tumidulum, Prings. Beitr., p. 69, t. 5, f. 2 (not 
 KutzTTig). Micr. Journ. 1866, p. 69. 
 
 CEdogonium Vaucherii, in Eabh. Alg. Eur. iii., 349, in part. 
 
 Ireland. 
 
 Plate LIX. Jig. 1. CEdogonium urbicwm, with oogoniuin and spermo- 
 gonia X 400. 
 
 S. Oospores ellipsoid or egg-shaped. 
 
 (Edogonium paludosuin. (Hass.} WUtr. Mon. (Edog. p. 14. 
 
 Oogonia single, ellipsoid, usually rather oblique, opening by 
 a pore above the middle ; oospores ellipsoid, distinctly filling 
 the oogonium (membrane of the oospore, when mature, longi- 
 tudinally costate ?) ; spermogonia 1-8 celled, scattered, usually 
 situate in the upper portion of the filament; spermatozoids 
 binate, often bom with an oblique division. 
 
 Size. Cells -01 5- '02 mm. by 3-7 times as long; oogonia 
 •039--048 X •066--084 mm. ; oospore •036--045 x •054--063 
 mm. ; sperm, cell OU-'Oie x •006--013 mm. 
 
 VesicuHfera paludosa, Hass. F. W. Alg. p. 199, t. 52, f. 3? 
 
 England. 
 
 Plate LIX. fig. 2. (Edogonium palvdosum with oogoniam and spermo- 
 gonia X 400. 
 
 B. Oogonia furnished with verticillate median processes. 
 
 a. Oospores subglobose. 
 
 (Edogoninm Itzigsohnii. D'Bary (Edog. p. 56, t 3, /. 29-32. 
 
 Oogonia single, ellipsoid, median processes 7-10, obtusely 
 conical, oogonia splitting round below the middle, opening by a 
 
CEDOGONIACEiE. 157 
 
 pore in the fissure, viewed from above stellate, with 7-10 rays, 
 the depressions between the rays deep and rounded ; oospores 
 globose, not filling the oogonium ; spermogonia 1-2 celled, 
 terminal cell obtuse or apiculate. 
 
 Size. Cells -OOS-'Ol mm. by 3-6 times as long ; oogonia 
 •034--038 X ■032--04mm. ; oospore •022--023 X •022--023 mm. ; 
 sperm, cell -OOS-'OOg x -OOg-'OlS mm. 
 
 Wittr. Mon. CEdog. p. 16. Kirch. Alg. Schles. p. 53. 
 Archer, in Quart. Journ. Micr. Sci., 1866, p. 63, Eabh. Alg. 
 Eur. iii., 352. 
 
 Ireland, Scotland. 
 
 This minute species Mr. Archer had found several times, and often 
 showing its peonliarly-lobed oogonium, but he had never found the male 
 fructification ; he believed the plant must turn out to be a dioecious 
 species ; he had sometimes noticed a minute notch-like depression on 
 the upper outer margin of the oogonium, probably indicating the " micro- 
 pyle." He drew attention to the character, not adverted to by De Bary, 
 that the apical or terminal joint of the filament possessed a short acute 
 spine or mucro. This in old plants, frequently is not to be seen, as the 
 terminal joint, or, indeed, considerable portions of the filaments, often 
 become detached, and chiefly in a young condition only are the plants 
 found entire. — Quart. Jottrn. I. c. 
 
 Plate LIX. fig. 3. (Edogonium Itzigsohnii, with oogonia and oospores ; 
 a, transverse section of oospore x 400, 
 
 h. Oospores subellipsoid. 
 
 (Edogoniunt excisum. Wittr. Sf Lund,., in Wittr. (Edog. Nov. 'p. 3, 
 t. 1,/. 1-4. 
 
 Oogonia single, biconically-oblong, median processes 9, 
 rounded, small, oogonia deeply cut round (circumscissile), 
 vertical view orbicular, margin slightly undulated ; oospores 
 ellipsoid, as if constricted in the middle, not filling the 
 oogonium. Spermogonia 1-2 celled, subepigynous or hypo- 
 gynous, terminal cell obtuse, upper part, of the filament curved. 
 
 Size. Cells ■0035--005 mm. by 5-6 times as long; Oogonia 
 •013--015 X ■018--025 mm.; oospore ■009--012 x -OIS-'OIS 
 mm. ; sperm cell ■003-'0035 X •006--007 mm. 
 
 Wittr. Mon. CEdog. p. 16. Archer, Quart. Journ. Micr. 
 Sci., 1875, XT., p. 102. 
 
 Ireland (rare). 
 
 PZate LIX. fig. 4. OSdogonxum excisum, with oogonia j a, section of 
 oospore x 400. 
 
 OEdogonium Archexianum, Cooke. 
 
 Monoecious ; oospore elliptic, its wall marked by somewhat 
 coarse longitudinal strise, not filling the cavity of the much 
 
158 NEMATOPHTOE^. 
 
 larger and elliptic oogonium; aperture of the oogonium very 
 high up, being quite close to the annular stris of the caps. 
 
 CEdogonivm Pringsheimianum, Archer, in Quart. Journ. 
 Micr. Sci., 1868, pp. 295. 
 
 Ireland. 
 
 There being already a species bearing the name of (Edogonium 
 Pringsheimii, which had priority, it became necessary to alter Mr. 
 Archer's specific name. We have not seen the species, and hence are 
 nnable to furnish a figure. Unfortonately no measurements are given 
 with the above very brief description, which is a doubtful economy of 
 space. It is the only moacecious species with striate elliptical 
 oospores. 
 
 Section ii. Dioecious species. 
 
 A. Dwarf males unicellular. 
 
 a. Oogonia furnished with verticellate median processes. 
 
 CEdogonium platygynum. Wiitr. (Edog. Nov.p.l. 
 
 Gynandrosporous. Oogonia single (very rarely binate), de- 
 pressedly obverse egg-shaped, median processes 7-12, rounded ; 
 oogonia cut round (circumscissile) below the middle, opening by 
 a pore seated in the fissure, vertical view -orbicular, margin 
 sinuate, with 7-12 (usually 8) depressions ; oospores rather de- 
 pressedly globose, nearly filling the oogonium, androsporangia 
 1-3 celled; terminal cell obtuse. Dwarf males obverse egg- 
 shaped, small, seated on the oogonia. 
 
 Size. Cells -006-01 mm., from 2-5 times as long ; oogonia 
 •021--03 X •016--024nim. ; oospore ■017--024 x •015--02 mm. ; 
 androsp. cell ■006--008 x •007--008 mm. ; dwarf males 
 ■0045--005 x •0085--0095 mm. 
 
 Wittr. Mon. (Edog. p. 17, t. 1, f. 5-9. Kirch. Alg. Schles. 
 p. 53. 
 
 Ireland. 
 
 Plate LIX. fig. 5. (Edogonium plaiygynum, with oogonium ; a, trans- 
 verse section of oospore x 400. 
 
 b. Oogonia destitute of median processes. 
 a Oospores globose or subglobose. 
 
 (Edogonium Rothii. (Le Clerc.') Prings. Beitr. 69, t. 5, /. 4. 
 
 Gynandrosporous. Oogonia single, or 2-6 continuous, glo- 
 bose, or rather depressedly globose, opening with a pore at the 
 middle. . Oospores rather depressedly globose, almost filling the 
 oogonia. Androsporangia 2-4 celled, subhypogynous ; dwarf 
 males obversely egg-shaped, seated on the oogonia. 
 
 Size. Cells •006--008 mm., S-S times as long; oogonia 
 ■02--021 X '016-019 mm. 
 
cEdogoniaoe^. 159 
 
 Wittr. Mon. (Edog. p. 18. Kirch. Alg. SoKl. p. 53. Eabh. 
 Alg. Eur. iii. 348. 
 
 Vesioulifera Rothii, Hassall, t. 53, f. 7 ? 
 Pvolifera Rothii, Le Clerc Prolif. 476, t. 23, f. 8 ? 
 
 Scotland, Ireland, England. 
 
 Mr. Archer mentions this plant as having been found by him with a 
 chain of as many as eleven oogonia in suooesaion. — Qua/rt. Micro. Jaurn,, 
 1866, p. 69. 
 
 Plate LIX. fig 6. (Edogonium Rothii with oogonia, androsporangia, and 
 dwarf males X 400. 
 
 CEdogonium Axeschougii. Wittr. Bisp. (Edog. p. 122. 
 
 Gynandrosporous. Oogonia 2-6, continuous or single, rather 
 depressedly globose, broadly cut round (circumscissile) in the 
 middle, opening by a pore in the fissure. Oospore exactly 
 globose, not by any means filling the oogonium. Androspo- 
 rangia 1-6 celled, hypogynous or subepigynous, or rarely 
 scattered, terminal cell (which sometimes is the androsporangium ), 
 obtuse, dwarf males obversely egg-shaped, seated on the oogonia. 
 
 Size. Cells •008-'012 mm., 4-6 times as long ; Oogonia 
 •038--039 X •036--04 mm. ; oospore •022--024 X •022--024 
 mm.; androsp. cells •01--011 X •01-'012 mm.; dwarf males 
 •006--007 X •014--015 mm. 
 
 Archer in Quart. Journ. Micr. Sci. 1872, xii., p. 422. Wittr. 
 Mon. CEdog. p. 19. 
 
 Ireland. 
 
 Plate LIX. fig 7. CEdogonium Areschougii with oogonia, andro- 
 sporangia, and dwarf males X 400 — after Wittrook. 
 
 CEdogonium pluviale. Nordst. Rai. Alg. Ewr. IVo. 2257. 
 
 Idio-androsporous. Oogonia simple, rarely 2-3 continuous, 
 obversely egg-shaped, globose, or nearly globose, opening by a 
 terminal operculum, fissure narrow ; oospores nearly globose, 
 almost filling the oogonium, terminal cell obtuse, filaments 
 bearing the androsporangia a little slenderer than the female 
 filaments ; androsporangia 6-10 celled ; dwarf males broadly 
 obverse egg-shaped, seated on the oogonia. 
 
 Size. Cells ■018-"028 mm., equal to three times as long ; 
 oogonia •034--039 X •034--045 mm. ; oospore ■032-'037x 
 •031--04 mm. ; androsp. cell •017--019 x •006-'0H mm. ; 
 dwarf males -01 x '015 mm. 
 
 Wittr, Mon. (Edog. p. 19. 
 
 CEdogonium diplandrum, Jur. Beitr. ffidog. p. 27, t. 1-3. 
 Vesiculifera dissiliens, Hass. P. W. Alg. 202, t. 50, f. 7. 
 
 Plate LIX. fig. 8. CEdogonium pluviale with oogonia and dwarf 
 male x 400. 
 
160 NfiMATOPHYCE^. 
 
 (Edogoniam undulatum. (BreJ.) Br. in Be Bary CEdog. p. 94. 
 
 Oogonia single or twin, ellipsoid-globose, or nearly globose, 
 opening by a pore below the middle ; oospores ellipsoid-globose, 
 or nearly globose, nearly filling the oogonia ; yegetative cells 
 four times undulatingly constricted ; terminal cell (which, some- 
 times is the oogonium) obtuse ; dwarf males obconical, seated 
 on the supporting cells. 
 
 Size. Cells "OlS-'Ol? mm., 3-5 times as long ; oogonia 
 •051--056 X •057--075 mm. ; oospores ■046--05 X -OdS-'Oe 
 mm. ; dwarf males, -OOO-Ol X "0. 
 
 Wittr. Mon. (Edog. p. 20. Kirch. Alg. Schles. p. 54. 
 Eabh. Alg. Eur. iii. 351. 
 
 Conferva undulata, Brebisson. 
 
 Cymatonema confervaceum, Kutz. Tab. iii., t. 47, f. 1. 
 
 Scotland. 
 
 Mate LIX. fig. 9. (Edogonium undulatum with oogonia and dwarf 
 male x 400. 
 
 (Edogonium Reinschii. May MSS. 
 
 Mr. Eoy has announced that the Cymatonema figured by 
 Reinsch {Gontrib. t. 6, /. 7) has been found in Scotland, and 
 is a genuine (Edogonium, but no further details have tran- 
 spired, and we know nothing of the fructification. The sterile 
 cells are figured on Plate LVII. fig. 28. 
 
 B. Dwarf males hicellular, spei-mogonia internal. 
 
 (Edogonium depressum. Prinys. JBeitr. 69, t. 5, f. 5 
 
 Gynandrosporous. Oogonia single, depressedly globose, 
 opening by a pore at the middle. Oospores depressedly 
 globose, not filling the oogonia ; androsporangia 2-celled ; 
 dwarf males oblong, obversely egg-shaped, one-third part 
 shorter than the oogonia on which they are seated. 
 
 Size. Cells •008-009 mm., 3-6 times as long ; oogonia 
 •028 X ^026 mm. ; oospores -023 X '017 mm. 
 
 Wittr. Mon. (Edog. p. 21. Kirch. Alg. Schles. p. 54. 
 Eabh. Alg. Eur. iii. 349. 
 
 Vesiculifera ceguale, Hassall, t. 53, f . 3 ? 
 
 Scotland. 
 
 Plate IiX.. jig. 1. (Edogonium, depregsum with oosporangia, cosporeB, 
 dwarf males, and biceUnlar androsporangia X 400. 
 
 C. Dwarf males bimulticeUular, spermogonia external, 
 a. Oospores with smooth membrane. 
 
 a Oospores globose or subglobose. 
 (Edogonium flavescens. (Bass.) Wittr. Disp. CEdog. p. 127 
 Idio-androsporous. Oogonia single, egg-shaped-globose 
 
CEDOGONIACE^. 161 
 
 (sometimes rather hexagonally globose), opening by a pore a 
 little above the middle ; oospores globose, not filling the 
 oogonia ; androsporangia 1-9 celled ; dwarf males a little 
 curved, seated on the supporting cell; spermogonia 1 (or 2 ?) 
 celled. 
 
 SizB. Cells •018--021 mm. by 4^ to 6 times as long ; 
 oogonia •049--052 x •051--060 mm. ; oospore •045--049 x 
 ■045--049 mm. ; androsp. cell •017--02 x •008--018 mm. ; 
 sperm, cells •009--01 x •015--02 mm. 
 
 Wittr. Mon. CEdog. p. 21, t. 1, f. 12-14. 
 
 Vesiculifera fiavescens, Hass. F. W. Alg. 206, t. 53, f. 9. 
 
 Plate LX. fig. 2. (Edogonium Jlavescens with single and twin 
 oogonia; a, androsporangia x 400. 
 
 (Edogonium Brauuii. Kutz. 8p. Alg. p. 366. 
 
 Gynandrosporous. Oogonia single, ellipsoid, globose, open- 
 ing with a pore at the middle ; oospores globose, not filling 
 the oogonia ; androsporangia 1-2 celled ; dwarf males a little 
 curved, seated about the oogonium, often on the supporting 
 cells ; spermogonia 1-celled. 
 
 Size. Cells "OIS-'OIS mm., 2-4 times as long ; oogonia, 
 •03--033 X •033--036 mm. ; oospore •027--029 x •027--029 mm. ; 
 androsp. cell ■014--015 x ■011--012 mm.; sperm, cell '005 x 
 •009 mm. 
 
 Prings. Beitr. p. 70, t. 5, f. 6. Wittr. Mon. CEdog. p. 22. 
 Kirch. Alg. Schles. p. 55. Archer in Quart. Journ. Micr. 
 Sci. 1866, p. 69. Eabh. Alg. Eur. iii. 349. 
 
 Britain, Ireland. 
 
 Plate LX fiff. 3. CBdogonium Braunii with oogonia,. oospores, and 
 dwarf males x 400. 
 
 (Edogonium maczandum. Wittr. Bisp. (EAog. 130, t. \,f. 3-5. 
 
 Oogonia single or twin (rarely three), obversely egg-shaped 
 or globosely egg-shaped, opening by an operculum, with a very 
 narrow fissure ; oospores globose or egg-shaped globose, not 
 filling the oogonia; terminal cell very shortly apioulate ; dwarf 
 males very much curved, seated on the oogonia (stem some- 
 times 2-3 celled) ; spermogonia many (to 7) celled. 
 
 Size. Cells •015-'O16 mm., 3-5 times as long; oogonia 
 •036--04 x •043--054 mm. ; oospore •031--034 x •033--039 mm. ; 
 sperm, cell "009 mm. 
 
 Wittr. Mon. CEdog. p. 24; Archer Quart. Journ. Micr. Sci. 
 1875, XV., p. 413. 
 
 Ireland, Britain. 
 
 Plate LX. jig. 4. (Edogonium macrandum with oogonia and dwarf 
 
 males x 400. Fig. 4. a, dwarf males seated npon the oogonium after 
 
 WittroBk. 
 
162 NEMATOPHYCK^. 
 
 OGdogonimn cTassiasculum. Wittr. IHsp. (Edog. p. 132. 
 
 Gynandrosporous. Oogonia single, or twin, globose egg- 
 shaped or neai-ly globose, opening by a pore above the middle ; 
 oospores ellipsoid-globose or globose ; membrane very thick, 
 almost filling the oogonia ; androsporangia 2-5 celled ; dwarf 
 males nearly straight, seated on or about the supporting cells ; 
 spermogonia 1 (?) celled. 
 
 Size. Cells ■027-*03 mm., 3^ to 5 times as long ; oogonia 
 •054--06 X •06--075 mm.; oospore -OSl-'OS? X-052--063 mm. ; 
 androsp. cells •026--028 x ■01--018 mm.; sperm, cell •007--009 
 mm. 
 
 Wittr. Mon. (Edog. p. 24. 
 
 Epping Forest (1882). 
 
 We have only found this species once in pools on the Longhton side 
 of Epping Forest, but the very thick coat of the oospore is remarkably 
 distinct, combined with other characters, so as to render its determina- 
 tion certain. 
 
 Plate LX^ fig. 5. (Edogonium crassiuscutum with oogonium and 
 dwarf males ; a, androsporangia ; o, mature oospore X ^iOO. 
 
 J. Oospores ellipsoid or egg-shaped. 
 
 (Edogoniam Boxisianam. {Le Clerc.) Wittr. Di^. (Edog. p. 132. 
 
 Gynandrosporous (or idio-androsporous ?). Oogonia single 
 or twin, obversely egg-shaped, opening by a pore above the 
 middle ; oospores obversely egg-shaped, almost filling the 
 oogonia ; supporting cells swollen ; androsporangia 2 ? celled, 
 terminal cell (which sometimes is the oogonium) obtuse, dwarf 
 males a little curved, seated on the supporting cells ; spermo- 
 gonia unicellular. 
 
 SizB. Cells •015--021 mm., 3-5 times as long ; supporting 
 cells •03--033 mm., twice as long ; oogonia ■045-05 X'06-'075 
 mm.; oospore •04--044 x •051--054 mm.; androsp. cell •017- 
 •018 X •015--02 mm. ; sperm, cell •Ol x -021 mm. 
 
 Wittr. Mon. (Edog., p. 25. Kirch. Alg. Schles. p. 55. 
 
 Prolifera Borisiana, Le Clerc Prolif. 175, t. 23, f. 6. 
 
 CEdogonium, apophysatum, Braun, in Kutz. Sp. Alg. p. 366. 
 Kutz. Tab. Phy. iii., t. 35, f. 5. Rabh. Alg. Eur. iii., 251. 
 
 CEdogonium setigerum, Vanp. lagt. (Edog. 17, t. 1. Archer 
 in Quart. Journ. Micr. Sci. 1866, p. 69. 
 
 Britain, Ireland. 
 
 See Mr. Archer's detailed account of this species in the place above 
 quoted. 
 
 Plate LX. Jig. 6 CEdogonium Borisianum, with oogonium and 
 thickened supporting cell bearing the dwarf males; a, androspore 
 X 400. 
 
CEDOGONIACBiE. 
 
 163 
 
 (Edogonium concatenatum. (.Hass.) WiUr. Won. (Edog. p. 25. 
 
 Gynandrosporous. Oogonia 2-6 continuous, or single, egg- 
 shaped, or quadrangularly ellipsoid, opening by a pore above the 
 middle ; oospores filling the oogonia, sporoderm delicately 
 porose; supporting cell swollen; androsporangia 2-4 celled; 
 terminal cell obtuse, dwarf males curved, seated on the sup- 
 porting cells; spermogonia 2-4 celled. 
 
 Size. — Cells ■025--04 mm., 3-10 times as long; supporting 
 cells •058--062 mm., 2^ times as long; oogonia ■07--083 x 
 •09--105 mm.; oospores -OeS-'OTe- X 087--095 mm. ; androsp. 
 cell •027-'028 x •03--036 mm. ; sperm cell •013--015 X -022- 
 •025 mm. 
 
 Kirch. Alg. Schles. p. 55. 
 
 Vesiculifera concatenata, Hassall F. W. Algae t. 51, f. 6. 
 
 (Edogonium apophysatum, Pringsh. Beitr. p. 71, t. 5, f. 9. 
 Eabh. Alg. Eur. iii,, 351, in part. 
 
 Britain. 
 
 Plate LX.I. Jig. 1. (Edogonium concatenatum, with oogonium and 
 thickened supporting cell bearing the dwarf males j a, androsporangia 
 X 400. 
 
 OBdogonium aczospoxum. J)e Bary. (Edog. p. 60, t.S,f. 1-12, 
 
 Idioandrosporous. Oogonia solitary, terminal, ellipsoid, 
 opening by a small apical deciduous (or evanescent) operculum ; 
 oospore manifestly filling the oogonia, membrane longitudinally 
 costate ; supporting cells often swollen, terminal cell obtuse ; 
 dwarf males curved, seated on the supporting cells, stem often 
 bicellular, upper cells of the stem very long ; spermogonia 1-2 
 celled. 
 
 Size. — Cells •01-"014 mm., 2-7 times as long; supporting 
 cells ■015-'018 mm., 2-3 times as long; oogonia •03-'035 X 
 •045--051 mm. ; sperm, cell ■006--008 x ■014--015 mm. 
 
 Archer in Quart. Journ. Micr. Sci. 1867, p. 80, 1868, p. 
 295. Wittr. Mon. (Edog. p. 16. Eabh. Alg. Eur. iii, 351. 
 
 Britain, Ireland. 
 
 The terminal oogonia are characteristic of this species, which can 
 scarcely be confounded with any other. 
 
 Plate LXI. Jig. 2. (Edogonium acresporum, with terminal oogonia, 
 after De Bary x 400. 
 
 (Edogonium ciliatum. (Hass.) Prings. Beiir. 70, t. 5, /. 8. 
 
 Gynandrosporous. Oogonia 2-7, continuous or single, egg- 
 shaped, opening by an operculum, with a broad fissure ; oospores 
 egg-shaped, nearly filling the oogonia ; androsporangia 2-8 
 celled, terminal cell setiform, dwarf males curved, seated on the 
 oogonium ; spermogonia unicellular. 
 
 2 A 
 
164 NEMATOPHYCB^. 
 
 Size. Cells ■015--023 mm., 2^ to 4 times as long; oogonia 
 •043--05 X -OSS-'OTS mm. ; oospore •04--046 X •047--057 mm. ; 
 androsp. cell •018--02 x •016-02 mm.; sperm, cell -OOS-'Ol x 
 •01--011 mm. 
 
 Wittr. Mon. (Edog. p. 27. Kirch. Alg. Schles. p. 56. 
 Rabh. Alg. Eur. iii., 347. 
 
 Vesiculifera ciliata, Hass. F. W. Algae 202, t. 52, f. 2. 
 
 CEdogonium pilifernm, Auers. Eab.'Alg. Sachs. No. 474. 
 
 Britain, Ireland. 
 
 Plate Ii^XI. fig. 3. (Bdoganium ciliatum, with oogonia and dwarf 
 males ; a, androsporangia ; b, small plant (after Pringsheim) ; c, andro- 
 spore X 400. 
 
 h. Membrane of oospore echinulate. Oospores globose. 
 
 (Edogoniam CleTeanum. Wittr. IHsp.CEdoff. p. 129. 
 
 Gynandrosporons. Oogonia single, subglobose, opening by a 
 pore below the middle ; oospores almost filling the oogonium, 
 globose, spinulose, spines conical spirally disposed; andro- 
 sporangia 4-6 celled, dwarf males a little curved, seated on the 
 supporting cell ; spermogonia unicellular. 
 
 Size. Cells •018-'026 mm., 3-7 times as long ; oogonia 
 •052--06 x ■059--063 mm.; oospores •049--057 x •051--059 
 mm.; spines -004 mm. long; androsp. cell ■018--022' x 009- 
 ■018 mm.; sperm, cell -OOS-OOSS x •014--016 mm. 
 
 Wittr. Mon. (Edog. p. 28. Kirch Alg. Schles. p. 56. 
 
 CEdogonium echinospermum, Pringsh. Beitr. 70, t. 5, f. 7. 
 Eabh. Alg. Eur. iii., 349, in part. 
 
 Ireland. 
 
 Plate IiXlI. fig. 1. CEdogonium Cleveanum with oogonia, and 
 eohinnlate oospores ; a, androsporangia x 400. 
 
 (Edogoninm eohinospezmam. Br. in EiUz. 1^. Alg. 366. 
 
 Gynandrosporons, or idiandrosporous. Oogonia single, 
 ellipsoid-globose, or nearly globose, opening by a pore at the 
 middle ; oospore almost filling the oogonia, glohose, echinulate ; 
 spines awl-shaped ; androsporangia 2-5 celled, dwarf males a 
 little curved, seated on the supporting cells ; spermogonia 
 unicellular. 
 
 Size. Cells ■018-"03 mm., 2-l-4i times as long ; oogonia 
 •04--05 X •042--057 mm. ; oospore ■038--047 x •038--049 mm. ; 
 spines -003 mm. long; androsp. cell ■021--025 x ■009--015 
 mm. ; sperm, cell •01--012 x •012--015 mm. 
 
 Archer in Quart. Journ. Micr. Sci. 1866, p. 69, 1867, pp. 
 80. Kutz. Tab. Phyc. iii., t. 36, f. 2. DBary (Edog. t. 3, f. 
 13-22. Wittr. Mon. (Edog. p. 29. Erch. Alg. Schles. p. 56. 
 Eabh. Alg. Eur. iii., 349. 
 
CEDOGONIACBjE. 
 
 165 
 
 Ireland, Scotland. 
 
 Of these two species with echiuulate oospores, the spines of the 
 former are broader at the base and oonical, whilst iu this they are slender, 
 and but slightly thickened downwards. 
 
 Plate hXIJ. fig. 2. CBdogonium ecMnospermum, with oogonia and 
 eohiunlate oospores x 400. ^ 
 
 S0B-SBCTION II. Dioecious, with elongated male plants. 
 Oogonia, not, or scarcely, swollen. 
 
 (Edogonium capillaze. {Lin.) Kutz. Phyc. Qen. 225, t. 12, 
 
 /. 1-10. 
 
 Oogonia single, not swollen, cylindrical, opening by a pore 
 above the middle; oospores globose or cylindrical-globose 
 (somewhat quadrangular in longitudinal section) not filling the 
 oogonia ; male plants the same or almost the thickness of the 
 female plants ; spermogonia 1-4 celled, alternate with the 
 vegetative cells : spermatozoids binate. 
 
 Size. Cells -OSS-'OSo mm., equal or twice as long ; oogonia 
 1^ times as long ; oospore •03--052 X -OSg-'OGS mm. ; sperm, 
 cell •03--048X-005--006 mm. 
 
 Kirch. Alg. Schles. p. 56. Kabh. Alg. Eur. No. 1180, 1417. 
 Wittr. Mon. CEdog. p. 30. 
 
 Conferva capillaris, Linn. Spec. PI. 1636. 
 
 (Edogonium regulare, Vaup. Beitr. CEdog. p. 213, t. 1, f. 
 1-10, not the Vesiculijera capillaris of Hassall. 
 
 Britain. 
 
 Plate LXII. fig. 3. (Edogonium eapiUare, with oogonia x 400. 
 
 b. Oospores manifestly swollen. 
 
 aa. Oospores globose, or nearly so. 
 
 (Edogonium calcazeum. Cleve in Wiitr. Disp. CEdog. p. 135. 
 
 Oogonia single (very rarely twin), depressedly globose, 
 opening by a pore at the middle ; oospores filling the oogonia, 
 male plants the same, or alrcost the same, thickness as the 
 female; spermogonia 2-5 celled; spermatozoids single [?). 
 
 Size. Cells ■011-'014 ram., 2-4 times as long; oogonia 
 •027--03 X ■021--023 mm. ; oospores •026--028 X ■02--021 
 mm. ; sperm, cell •01--011 x •009-'012 mm. 
 
 Wittr. Mon. CEdog. p. 82. 
 
 Vesiculifera compressa, Hass. F. W. Algae, 204, t. 53, f. 4. 
 
 (Edogonium compressnm, Eabh. Alg. Eur. iii., 348. 
 
 Britain. 
 
 Specimens from the warm tank in the Victoria House, Kew Gardens, 
 had shorter cells than usual. It has apparently a tendency to become 
 more or less coated with a deposit of lime. 
 
166 
 
 NEMATOP H YCE^ . 
 
 Plate LXII. jig. 4. (Edoyonium calcareum, with portions of male 
 and female plants ; a, female plant from Victoria tank, Kew Gardens 
 X 400. 
 
 CEdogonium cardiacum (Hass). Witbr. Disp. CEdog. 135. 
 
 Oogonia single, between heart-shaped and globose, opening 
 by a pore a little aboye the middle ; oospores globose, not fill- 
 ing the oogonia ; male plants a little slenderer than the female ; 
 spermogonia 2-10 celled ; spermatozoids binate, terminal cells 
 obtuse. 
 
 Size. Cells : fem. •018--03 mm. 2-7 times as long; cells : 
 male •015--025 mm. 2-6 times as long; oogonia -OS-O? x 
 •058- 086 mm. ; oospore •042-"06 x ■042-'06 mm. ; sperm, cell 
 ■015--021 X ■01--013 mm. 
 
 Wittv. Mon. (Edog. p. 33 ; Kirch. Alg. Schles. p. 57. 
 
 Vesiculifera cardiaca, Hass. F. W. Algse 203, t. 51, f. 4. 
 
 Vesiculifera pulchella, Hass. F. W. Algae 199, t. 50, f. 3. 
 
 CEdogonium pulchellum, Babh. Alg. Eur. iii. 356. 
 
 Britain. 
 
 Plate LXII. fig. 5. (Edoganium cardiacmn, oogonia with oospores 
 X 400. 
 
 (Edogonitun caibonicnm. Wittr. Mon. CEdog. p. 74. 
 
 Oogonia single or twin, obversely egg-shaped — or ovate — 
 globose, opening by a pore above the middle ; oospores ellipsoid- 
 globose or nearly globose, scarce filling the oogonia ; male plants 
 a little slenderer than the female ; spermogonia 2-5 celled ; 
 spermatozoids binate ; terminal cell obtuse. 
 
 Size. Cells: fem. •016-'03 mm. 3-6 times as long ; cells: 
 male •014--016 mm. 3-6 times as long; oogonia •043-"052x 
 •05-*072 mm. ; oospore •042-'05 x •046-"056 mm. ; sperm, cell 
 •013--014x-012--014mm. 
 
 Britain. 
 
 Plate LXIII. Jig. 1. (Edogoniuvi carbonicum with oospores. 1. a, 
 portion of male plant with spennogonia x 400. 
 
 (Edogonium, Pringsheimii. Cramer. Hedm. iii. 17 1, 1 c, f. 1-4. 
 
 Oogonia single or 2-6 continuous, somewhat egg-shaped 
 globose, opening by an operculum, with a very narrow and 
 scarcely distinct fissure ; oospores globose, not distinctly filling 
 the oogonia ; male plants a little slenderer than the female ; 
 spennogonia 2-10 celled, alternate with the vegetative cells in 
 the upper part of the filament ; terminal cell obtuse or rarely 
 shortly apiculate. 
 
 Size. Cells: fem. •012-*02 mm. 2-4 times as long ; cells: 
 male ■01l-"016 mm. 2-4 times as long; oogonia ■03-"043 X 
 
CEDOGONIAOB^. 167 
 
 •036--045 mm. ; oospore •028-'035 X ■028-"034 mm. ; sperm, 
 cell •01--015 X •006--009 mm. 
 
 Kirch. Alg. Schles. p. 57 ; Rabh. Alg. iii. 348. Rabb. Alg. 
 Enr. No. 790; Wittr. Mon. (Edog. p. 33, t. 1, fig. 16-17. 
 
 CEdogonium Nordstedtii, Wittr. (Edog. Nov. 6, t. 1, f. 7-8. 
 
 Britain. 
 
 Plate LXIII. fig. 2. CEdogonium Pringsheimii, with oogonia x 400. 
 (Edogonium punctato-stziatum. De Bary (Edog. t. 2,/. 15-16. 
 
 Oogonia single, depressedly globose, manifestly splitting 
 round (circumscissile) in the middle, opening by a pore in the 
 fissure ; oospore depressedly globose, nearly filling the oogonia ; 
 male plants a little slenderer than the female ; spermogonia 3-7 
 celled; spermatozoids single; membrane of the yegetative cells 
 and of the oogonia spirally punctate ; basal cell depressedly glo- 
 bose ; membrane vertically plicate. 
 
 Size. Cells: fem. •018-'022 mm. 2-6 times as long; cells : 
 male 'OIB-'OIQ mm. 2-6 times as long; oogonia ■048-'055 x 
 •038-'048 mm. ; oospore •044--051 x •035--043 mm. ; sperm, 
 cell •016--018 X •006--01 mm. 
 
 Barker. P., in Quart. Jour. Micr. Sci. 1871, p. 94; Rabh. 
 Alg. iii. 354. Rabh. Alg. Sachs. 214. Wittr. Mon. (Edog. p. 
 34. Rabh. Alg. Eur. No. 2276. Kirch. Alg. Schles. p. 57. 
 
 Ireland. 
 
 Distinguished by the cell wall being marked by spiral striae of a dotted 
 character, finely and closely set ; these seen in an empty cell, through 
 and through, the upper and lower striee being nearly in focus simul- 
 taneously produce a somewhat decussate appearance. 
 
 Flate LXIII. fig. 3. CEdogomv/m pmctato-striatum, with oogonium 
 X 40O. 
 
 bh. Oospores ellipsoid or egg-shaped. 
 (Edogonium Boscii (Ze Clerc). Wittr. lAsp. (Edog. Suec.p. 136. 
 
 Oogonia single, rarely twin, oblong -ellipsoid, opening by a 
 pore above the middle ; oospores ellipsoid, by no means filling 
 the oogonia, longitudinally costate ; male plants the same or 
 nearly the thickness of the female ; spermogonia 3-6 celled ; 
 spermatozoids binate; terminal cell slender and somewhat 
 hyaline. 
 
 Size. Cells '014-'02 mm. 4-6 times as long; oogonia 
 •04--045 X -08 --1 mm. ; oospore •036--04 x •06-'065 mm. ; sperm, 
 cell •013-'014x-006--009 mm. 
 
 Wittr. Mon. (Edog. p. 34. Rabh. Alg. Eur. iii. 357. Rabh. 
 Alg. Eur. No. 2198, 2369. 
 
168 
 
 NKMATOPHTCE^. 
 
 Vesiculifera Boscii, Hassall Algae t. 52, f. 3, 4, 5. 
 Frolifera ^oscii, Le Clerc Prolif. 474, t. 23, f. 5. 
 Vesiculifera elegans, Hass. Ann. Nat. Hist. 
 
 England. 
 
 Flate LXTII. fig. 4. (Edogonium, Boscii, with oogonia x 400. 
 
 (Edogonium tamidulum. Kutz. Dec. Alg. No. 60, 
 
 Oogonia single, ellipsoid egg-shaped, opening by a pore above 
 the middle, almost filling tbe oogonium ; male plants a little 
 slenderer than the female ; spermogonia 6-45 celled ; sperma- 
 tozoids binate. 
 
 Size, Cells : fem, •018-025 mm, 3J-5 times as long ; 
 cells: male -Olo-'OIS mm. 4 times as long ; oogonia •056-'058 
 X "OTS-'Og mm.; oospore ■049--054 x •061-'068 mm.; sperm, 
 cell •015--017 X ■009--012 mm. 
 
 Wittr. Mon. (Edog. p. 35. Kirch. Alg. Schles. p. 58 (not 
 of Pringsheim) . 
 
 Ireland. 
 
 Plate LXIII. fig. 5. (Edogonium tumiduluni with oogonium. 5 a, 
 portion of male plant with spermogonia x 400. 
 
 CEdogonium Landsboioughii {Hass). Wittr. Man. (Edog. p. 35. 
 
 Oogonia single, rarely twin, obversely egg-shaped, opening 
 by a pore above the middle; oospores obversely egg-shaped, 
 filling the oogonia (or rarely ellipsoid and not filling the 
 oogonia) ; male plants a little slenderer than the female ; sper- 
 mogonia 5-25 celled ; spermatozoids binate, with a vertical 
 division ; terminal cell obtuse. 
 
 Size. Cells : fem. -OSS-'OSe mm. 4-6 times as long : cells : 
 male ■031--033 mm. 4-6 times as long ; oogonia •068--075 x 
 •1--12 mm. ; oospore •057-"07 X ■075-1 mm. ; sperm, cell 
 •027--03x-009--012mm, 
 
 Kirch. Alg. Schles. p. 58. 
 
 (Edogonium rivulare, Eabh. Alg. iii. p. 350, in part. 
 
 Vesiculifera Landsboroughii, HassaW, F. W. Algse t. 51, f. 2. 
 
 (Edogonium gemellipai-nm, Hantsch, Rab. Alg. Eur. 1118. 
 
 (Edogonium gemelliparum v. major, Wittr, Disp. CEdog, p, 
 137, 
 
 Britain, 
 
 Plate LXIV. fig. 1, (Edogonium Landsiorovghii, with oogonia anrl 
 oospores x 400. 
 
 var $. gemelliparam (Prings). Wittr. 3Ion. (Edog. p. 36. 
 
 Smaller than the typical form. Oogonia egg-shaped ; oospores 
 filling the oogonia ; terminal cell very long, somewhat hyaline. 
 
(EDOGONIAOB^. 169 
 
 Size. Cells : fem. ■02--027 mm. 3-5 or 8 times as long ; 
 oogonia •Qbb--0b7 x -Olb-OS mm.; oospore ■049--051 X 
 •065--069 mm. 
 
 Kirch. Alg. Schles. p. 58. Archer in Quart. Journ. Micr. 
 Sci. 1866, p. 69. 
 
 (Edogonium gemelliparum, Pringsh. Beitr. p. 71. 
 
 Ireland. 
 
 Plate LXIV, fig. 2. (Edogomum Xandsioroughii, variety gemelli- 
 parum, with oogonium x 400. 
 
 (Edogonium zivulaze (ie Clerc). Braun, Chytr.p. 23, t. 1,/. 1-10. 
 
 Oogonia single, or 2-7 continuous, obversely egg-shaped, 
 opening by a pore above the middle ; oospores obversely egg- 
 shaped, rarely ellipsoid or nearly globose, not by a long way 
 filling the oogonia ; male plants a little slenderer than the 
 female ; spermogonia 3-9 celled; spermatozoids binate. 
 
 Size. Cells : fem. •045--045 mm. 3-8 times as long; cells: 
 male •03--036 mm. 4 times as long ; oogonia •07-'085 x ■13--16 
 mm. ; oospore ■055-'07 x •065-'l mm. ; sperm, cell •021-'028 x 
 •014--016 mm. 
 
 Wittr. Mon. (Edog. p. 36. Kirch. Alg. Schles. p. 58. 
 Eabh. Alg, Eur. iii. 350 in part. 
 
 Prolifera rivularis, Le Clerc Prolif. 472, t. 23, f. 1. 
 
 Scotland. 
 
 Plate LXIV f^. 3. CBdogonium rivulare, ■^ith. oogonium and oospore 
 X 400. 
 
 Species of which the organs of fructification are imperfectly 
 
 known. 
 
 a. Oospores globose or sub-globose. 
 
 (Edogonium delicatulum. Kutr. Tab. in., t. 33, /. 3. 
 
 Pallid, basal cell scarcely lobed at the base, affixed, cells 
 cylindrical; oogonia subglobose, inflated, a little extended at 
 either pole ; oospore perfectly globose. 
 
 Size. Cells 'OOS-'OOe mm., 3 times as long ; oogonia -02 x 
 •017 mm. ; oospores •012--014 mm. 
 
 Eabh. Alg. Eur. 355. Eabh. Alg. Ex. No. 1156. 
 
 Deeside (Scotland). 
 
 Plate LX VI. Jig. 7. (Edogonium delicatuhim, with oogonia x 400. 
 
 (Edogonium tenellum. Kutz. Tab. in., t. 33, f. 9. 
 
 Basal cell two to three lobed, at first fixed, terminal joint 
 obtuse, cells cylindrical or rather clavate ; oogonia very much 
 inflated ; oospore globose, bright orange. 
 
170 NEMATOPHYCE^. 
 
 Size. Cells -OOD-'Oll mm., 4-8 times as long ; oogonia 
 •025 mm. diam ; oospore -Oie-'OIS mm. 
 Eabh. Alg. Eur. iii., 355. 
 
 Deeside (Scotland). 
 
 Plate LXVI. fig. 6. (Edogonivm tenettum, with oogonia x 400. 
 
 (Edogoniani hexagomum. Kutz. Tab. iii., t. 35, /. 3. 
 
 Oogonia almost globose ; oospores globose, rufous-brown, not 
 filling the oogonia ; basal cell bifurcate ; terminal cell often 
 setigerous. 
 
 Size. Cells •011-'013 mm. 2-4. times as long ; oogonia 
 •025 X ^025 mm.; oospore •016 mm. 
 
 Rabh. Alg. Eur. iii. 354. 
 
 Vesiculifera hexagona Hassall Algae t. 53, f. 11-12. 
 
 Deeside (Scotland). 
 
 Plate LXVl. fig. 8. (Edogonium hexagonwm, with oogonia x 400. 
 (Edogonium Londinense. Wittr. Man. ^dog. p. 39. 
 
 Monoecious 7 oogonia twin or single, globose, cut round (cir- 
 cumscissile) in tbe middle, opening by a pore seated in the 
 fissure ; oospores globose, almost filling the oogonia ; spermo- 
 gonia (or androsporangia ?) 1-2 celled, hypogynous. 
 
 Size. Cells •01-'015 mm. 1^ to 5 times as long ; oogonia 
 •033--035 X •033--043 mm. ; oospore •027--032 x •027-032 
 mm. ; sperm, cells ■026-^027 X ■027-^029 mm. 
 
 England. 
 
 Plate LXV. f^. 4. (Edogoniam, Londineme with oogonia x 400. 
 
 (Edogoniam fasciatum. Kutz. Tab. iii., t. 34, /. 6. 
 
 Oogonia somewhat globose ; oospores globose, rufous-brown, 
 almost filling the oogonia ; basal cell usually bilobate, terminal 
 cell obtuse. 
 
 Size. Cells •028-"03 mm., twice as long ; oogonia -04 mm. ; 
 oospore •03-'032 mm. 
 
 DeBary CEdog. t. 3, f. 23-28. Rabh. Alg. Eur. iii., 354. 
 
 Vesiculifera fasciata Hassall Algse t. 53, f. 6. 
 
 Deeside (Scotland). 
 
 PlaieLXVI.f^.2. (Edogonivm faiciatum, -wiOi oogojost x -400. 
 
 (Edogonium capillaceiun. Kutz. Phy. Gen. 255. 
 
 Dark green, basal cell attenuated downwards, bifid, terminal 
 point obtuse, cells sub-cylindrical ; oogonia broadly elliptical, 
 2-4 often contiguous, opening by a lateral pore ; oospore nearly 
 
CEDOGONIAOB^. 171 
 
 globose, rufous-brown wheu mature, loosely involved in the 
 oogonium. 
 
 Size. Cells ■02--025 mm. l|-3 times as long; oogonia 
 •05 X "04 mm. ; oospore •03-"032 mm. 
 
 Kutz. Tab. iii., t. 39, f. 6. Eabh. Alg. Eur. iii., 353. 
 
 Deeside (Scotland). 
 
 Plate LXVI. fig. S. (Edogoniuvi capillaceum, -with, oogor^ x 400. 
 (Edogoniuni Hutchinsise. Wittr. Mon. CEdog. p. 42. 
 
 Oogonia single, rather depressedly to somewhat egg-shaped 
 globose, opening by a pore above the middle ; oospores filling 
 the oogonium, epispore punctate with little warts ; supporting 
 cells swollen. 
 
 Size. Cells •03-'035 mm., 4-6 times as long; oogonia 
 •062--075 X -OeS'-OgS mm. ; oospores •06-'073 x •055- -072 
 mm. ; supporting cells •04--05 mm, 2-4 times as long. 
 
 Ireland. 
 
 The figure is taken from original specimens from Miss Hutohius in the 
 Eoyal Herbarium at Kew. 
 
 Plate LXV. fig, 1. (Edogonivm HutcJUnsim, with oogonia x 400. 
 
 CEdogonium pzinceps. (Hass), Wittr. Mon. QiJdog.p.iZ. 
 
 Oogonia single, somewhat egg-shaped globose, opening with 
 a pore above the middle ; oospores globose, not distinctly filling 
 the oogonium. 
 
 Size. Cells ■037-'045 mm. l5-2:|^ times as long ; oogonia 
 061--075 x -OeS-'OS mm. ; oospore -OSS-'OeG x •06--065 
 mm. 
 
 Vesiculifera princeps Hass. F. W. Alg. 195. 
 
 Vesiculifera capillaris Hass. F. W. Alg. 195, t. 50, f. 1-2. 
 
 England. 
 
 Plate LXV. fig. 2. (Edogoniwn ynncep*, with oogonia and (a) spermo. 
 gonia (?) X 400. 
 
 b. Oospores subelliptic or oval, 
 (Edogonium longatum. ^«fo. Sp. Alg. p. 364. 
 
 Oogonia single (often solitary, terminal), rarely 2-3 con- 
 tinuous, ellipsoid, opening by an operculum, with a narrow 
 fissure ; oospores globosely-ellipsoid, scarcely filling the 
 oogonium ; terminal cell obtuse. 
 
 Size. Cells ■005--006 mm. 2-3 times as long; oogonia 
 ■016--017 X ■021--024 mm. ; oospores •015--01 6 x •0175--0185 
 mm. 
 
 2 B 
 
172 NEMATOPHYCB^. 
 
 Kutz. Tab. Phy. iii., t. 33, f. 6. Wittr. Mon. (Edog. p. 38. 
 
 Britain. 
 
 plate LXIV. fig. 4. (Eijogomvam, longatvm, parasitic npon another 
 species, with oogouia x 4O0. 
 
 (Edogoniam Tesicatam. QLyngi.) WUtir. Mon. (Edog. p. 39, 
 
 Oogonia single, ellipsoid, globose, opening by an operculum, 
 with a narrow fissure ; oospores ellipsoid-globose, almost filling 
 the oogonium. 
 
 Size. Cells •017-*21 mm. l;^-3 times as long ; oogonia 
 •043--045 X -OSl-'Oe mm. ; oospore •037--038 X •041--042 
 mm. 
 
 Kirch. Alg. Schles. p. 59. 
 
 Conferva vesicata Lyngb. Hydro. 144, t. 47, f. D 1. Eng. 
 Bot. t. 2476. 
 
 Scotland. 
 
 Plate LX7. Jig. 5. (Edogonivm vesicatum, with oogoniTim x 400. 
 
 (Edogoniam grande. Kvtz. Tab. Phy. in, t. 37, f. 1. 
 
 Oogonia oval-elliptic, nearly twice as long as broad ; oospores 
 oval-elliptic, entirely filling the oogonia ; basal cell contracted 
 towards the base, then dUated and discoid ; terminal cell 
 obtuse. 
 
 Size. Cells -025- -035 mm. 3-4 or 5 times as long ; oogonia 
 •1 X '07 mm.; oospore '09 x "065 mm. 
 
 DeBary (Edog. t. 2, f. 1-14. Kabh. Alg. Enr.'iii., 353. 
 
 Scotland. 
 
 Plate LXFI. ilg. 4. (Edjogoimim grands, with oogonium x 400. 
 (Edogonium gigantenm. Kutz. Phyc. Oerm.'g.TM. 
 
 Oogonia single, a little swollen, cylindrically egg-shaped, 
 opening with a pore above the middle ; oospores cylindrically 
 ellipsoid, nearly filling the oogonia (sometimes flask-shaped, 
 short necked, and then filling the oogonia), epispore delicately 
 scrobiculate, supporting cells rather swollen. 
 
 Size. Cells ■03-'024 mm. 2-4^ times as long ; supporting 
 cells •054-'06 mm. 1^1 j times as long ; oogonia •057-'069 x 
 •078--106 mm. ; oospore •054--065 x •075--103 mm. 
 
 Kutz. Tab. Phyc. iii, t. 37, f. 2. Wittr. Mon. (Edog. p. 42. 
 Kirch. Alg. Schles. p. 59. 
 
 VesicuUfera lacustris Hass. P. W. Algae 198, t. 52, f. 1. 
 
 (Edogonium lacustre Eabh. Alg. Eur. iii, 356. 
 
 Plate LXV. fig. 3. (Edogonium giganteum, with oogonia x 400. 
 
CEDOQONIAOE^. 173 
 
 (Edogoniuin crassum. (Mass.) Wiiir. Gotl. Sotv. Alg. p. 20, 1. 1. 
 
 /. 4-6. 
 
 Oogonia single (rarely twin), obverselj egg-shaped ellipsoid, 
 a little swollen, opening by a pore above the middle ; oospores 
 ellipsoid, not filling the oogonia. 
 
 Size. — Cells -OSS-'OSS mm. 2-5 times as long ; oogonia 
 •065--07 X •1--125 mm. ; oospore •06--066 X ■08--11 mm. 
 
 Wittr. Mon. (Edog. p. 43. Kirch. Alg. Schles. p. 59. 
 
 Vesiculifera crassa Hass. Alg. t. 51, f. 1. 
 
 Plate tXVJ. Jig, 1. CEdogonium orassum, with oogonium x 400. 
 (Edogonium subsetaceum. K-ute. Spec. p. 368. 
 
 Basal cell dilated and discoid at the base, rather lobed, 
 terminal joint obtuse ; oospores broadly oval, golden red, closely 
 involved in the oogonium. 
 
 Size. Cells •04-*052 mm. equal or twice as long ; oogonia 
 •065 X '055 mm. ; oospore '06 x '05 mm. 
 
 Kutz. Tab. iii, t. 41, f. 1. Rabh. Alg. Eur. iii, 352. 
 
 Deeside (Scotland). 
 Plate LXVI. fig. 5. (Edogonium suisetaeeum, with oogonium x 400. 
 
 Genus 66. BULBOCHCETE. Ag. (1817.) 
 
 Filaments articulated, branched, joints thickened upwards, at 
 or about the apex bearing set*, which are straight, hyaline, 
 colourless, more or less elongated, bulbous at the base, cell 
 membrane usually punctate ; oogonia opening by a lateral pore 
 above the middle ; mature oospore red ; monoecious or 
 dioecious. 
 
 Reproduction sexual as in CEdogonium. In the dioecious 
 
 species nannandrous (dwarf males). 
 
 The following arrangement of the British spacies is based on that of 
 Prof. Wittrook :— 
 
 BULBOCHCETE. 
 
 Sect. 1. Oogonia globose or subglobose, patent ; oospores with the same 
 form, and filling the oogonia. Dioecious. 
 
 A. Dmarf males unicellular. 
 
 None. 
 
 B. Ihva/rf males iicellula/r. 
 
 a. Basal cell of the stem of the male plants shorter than the 
 spermogonia, 
 B. intermedia, DBary, 
 B. polyandra, Gleve. 
 B. Brebiesonii, Xutii. 
 B. setigera, Ag, 
 
174 NEMATOPHYCE^. 
 
 h. Sasal oell of the stem of the male plaats longer thcin the 
 Bpermogonia. 
 
 B. gigantea, Pring. 
 Sect. 2. Oogonia ellipsoid or snbellipsoid ; oospores of the same form, 
 filling the oogonia, epispore longicndinally costate, costae more or less 
 crennlate. 
 Sab-Sect. 1. Species monoecious. 
 
 B. mirabilis, Wittr. 
 Sub-Sect. 2. Species dioecious. 
 
 A. Dissepiment of supporting cell obsolete. 
 
 B. pygmoea, Pring. 
 
 B. Dissepiment of supfiorting cell present. 
 
 Bt' insignis, Frings. 
 B. rectangolaris, Wittr. 
 Species of which the organs of fructification are imperfectly known. 
 B. gracilis, Prings. 
 
 Section 1. Oogonia globose, or subglobose ; dicBcious. 
 
 B. Dwarf males hicelhilar. 
 
 Bulbochcete intexmedia. DeBary (Edog. 72, t. 4, /. 1-7. 
 
 Oogonia somewhat depressedly globose, seated beneath the 
 androsporangia, dissepiment of the supporting cell in the 
 middle ; epispore delicately crenulate (rarely seen) ; andro- 
 sporangia 1-2 celled, epigynous, rarely scattered, dwarf males 
 seated on the oogonia, stem slightly curved. 
 
 Size. Cells "OIT-'OIQ mm. 1^3 times as long ; androspore 
 cells -013 X-01 mm. ; oogonia •04--048 X •031--04mm. ; dwarf 
 males •009--01 X ■024-026 mm. 
 
 Wittr. Mon. (Edog. p. 44, t. 1, f. 18. Kirch. Alg. Schles. 
 p. 60. Eabh. Alg. Eur. iii, 358. 
 
 Britain, Ireland. 
 
 Plate LXVII. fy. 1. Bulbochoste intermedia, with oogonia, after 
 DeBary x 400. 
 
 Bulbochoete polyandra. Cleve. Wittr. Disp. p. 140. 
 
 Idio-androsporous. Oogonia snb-depressedly globose, seated 
 beneath terminal setce or vegetative cells ; dissepiment of sup- 
 porting cell above, or rarely about the middle ; epispore deli- 
 cately crenulate or nearly even ; androsporangia 4-10 celled ; 
 dwarf males seated on the oogonia, stem a little curved. 
 
 Size. Cells •015-'02 mm., 3-5 times as long; oogonia 
 •035--046 X •032--038 mm. ; androspore cell •013--014 x 
 ■012--015 mm. ; dwarf males •008--009 X -023 mm. 
 
 Wittr. Mon. (Edog. p. 46, t. 1, f. 19, 20. Kirch. Alg. Schles, 
 p. 61. 
 
 Britain, Ireland. 
 
 Plate LX71I. jig. 2, BulbocTicete polyandra, with oogonia ; 2a, with 
 fmdrosporaDgia x 400, 
 
CEDOOONIACB^. 175 
 
 Bulbochcete Bxebissonii. Sutz. Jab. Fhyc, it, 19, t. 86. 
 
 Oogonia obcordate-globose, truncate below, erect, seated 
 beneath terminal setae or androsporangia, dissepiment of sup- 
 porting cell low, epispore delicately crenulate ; androsporangia 
 2-3 celled, scattei'ed or epigynous ; dwarf males seated on the 
 oogonia, rarely around it, stem straight, or nearly so. 
 
 SiZB. Cells -017- -02 mm. by 3-4|- times as long; andro- 
 spore cells -015 x -OIS-'OIS mm. ; oogonia •042-'05 x 
 •037--045 mm. ; dwarf males •01--012 x •028--033 mm. 
 
 Wittr. Mon. CEdog. p. 46. Eabh. Alg. Eur. Exs. 1055. 
 Eabh. Alg. Eur. iii. 359. 
 
 Ireland. 
 
 Plate LXVII. fig, 3. Bulhochosie Brehissonii, with oogonia, and dwarf 
 males x 400. 
 
 Bulbochcete setigexa. Aff. Syn. Alg. Scan. p. 71. 
 
 Oogonia depressedly, somewhat quadrangularly globose, 
 seated beneath terminal setse, or beneath androsporangia ; mem- 
 brane of the oogonium after fertilisation thickened ; dissepiment 
 of supporting cell a little above the middle, or at the middle ; 
 epispore granulated ; androsporangia scattered or epigynous, 
 bicellular; dwarf males seated upon or about the oogonia, stem 
 straight. 
 
 Size. Cells •025-'028 mm., 2^-5 times as long ; andro- 
 spore cells •018--02 X •014--018 mm. ; oogonia •075--08 X 
 •06--065 mm. ; dwarf males, •012--013 X ■034--036 mm. 
 
 Wittr. Mon. (Edog. p. 47. Prings. Beitr. 72, t. 6, f. 3. 
 Kirch. Alg. Schles.p. 61. Eabh. Alg. Bur. iii., p. 358. Hass. 
 Alg. t. 54, f. 1-4. Eng. Bot. ii. t. 2472. Eng. Fl. v, p. 350. 
 
 Conferva vivipara Dillw. Conf. t. 59. Eng. Bot. i, 2086. 
 
 Bulbochcete Rothii Gray. Arr. 1, 321 (?). 
 
 Britain, Ireland. 
 
 Plate XL7III. f^. 1. BulbocTuete setigera, with oogonia and dwarf 
 males ; a, b, c, development of yonng plants x 400. 
 
 Bulbochcete gigantea. Prings. Beitr. 11, i. 6,/. 1. 
 
 Idio-androsporous? Oogonia rather depressed obcordate- 
 globose, seated beneath terminal setse, rarely beneath vegetative 
 cells ; dissepiment of supporting cell at or a little above the 
 middle ; epispore verrucose ; dwarf males a little longer than 
 the oogonia, and seated upon it ; stem twice as long as the 
 spermogonium, arcuate. 
 
 Size. Cells •024--027 mm. by 2-3 times as long ; oogonia 
 •062-'066 X •051--058mm. ; stem of dwarf males •011--012 X 
 '04--045 mm. ; sperm, cell -OlS-'Oli x •02.-022 mm. 
 
176 NEMATOPHYCE^. 
 
 Wittr. Mon. (Edog. p. 48. Kirch. Alg. Schles. p. 61. 
 Eabh. Alg. Eur. iii., p. 357. Qaart. Jouiii. Mior. Sci., 1866, 
 p. 276. 
 
 Britain, Ireland. 
 
 Plate LXVIIl. Jig. 4. Btdbochcete gigantea, with oogoninm and 
 dwarf male x 400. 
 
 Section 2. Oogonia ellipsoid or subellipsoid. 
 
 Sub-Section 1. Species monoecious. 
 
 Bulliochcete miiabilis. Wittr. IHsp. (Edog. 137, t. 1,/. 8, 9. 
 
 Oogonia ellipsoid, or rather oblong-eUipsoid, patent, or rarely 
 erect, seated beneath terminal setse or vegetative cells ; spermo- 
 gonia 2-4 celled, erect (rarely patent), subepigynous, or 
 scattered. 
 
 Size. Cells •016-"02 mm. l:^lf times as long ; oogonia 
 •027--035 X •046--056 mm. ; sperm, cell •01--012 ■><. •007--009 
 mm. 
 
 Wittr. Mon. (Edog. p. 50. 
 
 Britain, Ireland. 
 
 Plate LXVIIL fig. 2. Btdbochcete mirabUis, with oogonia and 
 androsporangia x ifiO. 
 
 Sub-Section 2. Species dioecious. 
 Bulbochoete pygmoea. Wittr. Bisp. (Edog.p.Ul. 
 
 Oogonia ellipsoid, patent, seated beneath terminal set», or 
 vegetative cells, in longitudinal section rather quadrangular ; 
 androsporangia scattered, dwarf males seated about the oogonia. 
 (Filament at first short, and curved.) 
 
 Size. Cells ■012-'015 mm. x a third part shorter or equal ; 
 oogonia •023-'025 x ■034-'04 mm. ; stem of dwarf males 
 ■011--012 X •015--018 mm.; sperm cell •007--0075 x 
 •007--0075 mm. 
 
 Wittr. Mon. (Edog. p. 52; Quart. Journ. Micr. Sci. 1870, 
 p. 89. 
 
 Bulbochoete pygmcea, /3. minor, Prings. Beitr. p. 74, t. 6, f. 
 10. 
 
 Ireland, Britain. 
 
 PlcOe LXVIIL fig.^. Vlantoi Btdbochcete pygmcea, ynthoogomum 
 and (a) section of oospore x 40O. 
 
 Bul'bochoete insignls. Priiigs. Beitr. 72, t. 6, f. 7. 
 
 Oogonia ellipsoid, patent or erect, seated beneath andro- 
 sporangia or terminal setae ; epispore delicately transversely 
 striate ; androsporangia epigynous, or rarely scattered ; dwarf 
 males seated about or upon the oogonia. 
 
OEDOaONlAOE-E. 177 
 
 Size. Cells •02--025 mm. 2^-41 times as long ; oogonia 
 •046--05 X •07--1 mm. ; androspore cell •016--02 x •02--025 
 mm. ; stem of dwarf males •017--019 X •029--031 mm. ; sperm, 
 cell •01--011 X •0075--008 mm. 
 
 Wittr. Mon. CEdog. p. 55. Kirch. Alg. ScWes. p. 62. 
 
 Rabh. Alg. Eur. iii. 360. 
 
 Bulbochoete Pringsheimiana Arch. Proc. Dubl. Micro. Club p. 
 38, t. 4. 
 
 Ireland. 
 
 Flate LXVII, fig, 4, BiilhooTuste insignia, with oogonium and dwarf 
 male x 400, 
 
 Bulbochoete rectangulazis. ff^itir. Disp. (Edog. p. Ii2. 
 
 Oogonia ellipsoid, patent, or rarely erect, seated beneath 
 terminal setae, or androsporangia, or rarely beneath Tegetative 
 cells; androsporangia scattered or epigynous ; vegetative cells 
 somewhat rectangular in longitudinal section (horizontal divi- 
 sion of vegetative cells often occurs). Branches of the plant 
 few and very long ; dwarf males seated about or upon the 
 oogonia. 
 
 iSizB. Cells •019-*023 mm., l;J^-2 times as long ; oogonia, 
 •03--039 X ■048--055 mm. ; androspore cell -OlS-'Oie x •016-'027 
 mm.; stem of dwarf males -OIS-'OIS x •022-"027 mm. ; sperm, 
 cell -OOS-'OOgS X ■0055--0065 mm. 
 
 Wittr. Mon. (Edog. p. 56, t. 1, f. 22-24. 
 
 Ireland. 
 
 Plate ZXVI2I. fig, 3. Bulbochcete rectangiila/ns, with oogonia and 
 dwarf male x 400. 
 
 Species of which the organs of fructification are imperfectly 
 
 known. 
 
 Bulbochcete gracilis. Brings. Beitr, 74, t. 6,/. 9. 
 
 Monoecious (?). Oogonia oblong-ellipsoid, patent or rarely 
 erect, with vegetative cells above ; supporting cells without 
 dissepiment (?). 
 
 Size. Cells ■013--014mm., 1^ to 1-^ times as long ; oogonia 
 •021-'024 X ■049--054 mm. 
 
 Wittr. Mon. (Edog. p. 57. Eabh. Alg. Eur. iii., 359. Quart. 
 Journ. Micr. Sci. 1870, p. 89. 
 
 Ireland. 
 
 Plate LXVI. fig. 9. Bulbochcste graciUs, with oogouinm x 400. 
 
178 nematophtobjE . 
 
 Family YI. ULOTRICHB^. 
 
 Algffi growing either in fresh water ( Vlothrix), or marine or 
 sub-marine (Hormiscia), or terrestrial {Bormidium, Schizo- 
 gonium), either of a bright green or yellowish green colour. 
 Threads very shortly articulate, simple, very rarely dividing into 
 single branches, free, now and then laterally connate in bands 
 (^Schizogonium). 
 
 Primitive cells always many times longer than their diameter, 
 after repeated division equal, or shorter (rarely a little longer), 
 all fertile. Cell-membrane either thin {ULothrix, Bormidium) 
 or thick, sometimes very thick, and distinctly lamellose {Hor- 
 miscia). Cell-contents at first effused, parietal, including a 
 starch granule, after simple or repeated division transmuted 
 into gonidia. 
 
 Gonidia of two kinds, Macrogonidia sphserical, ovoid, or 
 ovate-oblong, rounded at one pole, and acute at the other, fur- 
 nished with 2 or 4 vibratile cilia, often germinating in the 
 mother-cell without sexual fertilization. Microgonidia much 
 smaller, of similar form, furnished with two cilia at one ex- 
 tremity. Both kinds of zoogonidia produced within the cells of 
 the threads, emitted either by a poriform opening in the mother- 
 cell, or by the splitting or breaking up of the mother-cell. 
 
 For detailed information on this family consult Brann's " Rejnvenes- 
 oenoe" (Eay Society), pp. 148, 161, 184, 208, 223 j Dr. A. Dodel, " die 
 Kranshaar-AJge," Xflothrias zomata, in Pringsheim's " Jalirbnoher," t. x. ; 
 Cienkowsky " Zur Morphologie der Ulotricheen '' (1876) ; Thnret, in 
 " Ann. des Sciences NatnrelleB," xiv. (1850), p. 222 ; and Dr. Braxton 
 Hicks, in " Qnarterly Journal of Microscopical Science," 1861, p. 157. 
 
 Gvmss 66. BORBIISCIA. Ares. (1866.) 
 
 Articulate thread fixed by the basal cell, which is attenuated 
 downwards; simple, or now and then emitting branchlets. 
 Cells abbreviated, enclosed by a thick cell-membrane, which is 
 often manifestly lamellose. Cell-contents green, parietal, 
 including an amylaceous granule. 
 
 Propagation by macrogonidia and microgonidia. — Rabh, 
 Alg. Eur. in. 361. 
 
ULOTUICHBJT.. 179 
 
 The filaments are sometimes cylindrical, sometimes toruloae like a 
 rosary, in consequence of the barrel-like inflation of the separate cells ; 
 sometimes stretched out, sometimes frilled and interlacing each other, 
 with a relatively thicker stratified membrane. Vegetative or asexual re- 
 production is eiSected by macrozoospores, "which originate 1-4 in a cell, 
 and after becoming covered with a transparent bladder make their exit 
 through an opening formed in the lateral wall of the mother-cell. The 
 macrozoospores are of a thick, short, pear-shape, furnished with four 
 cilia, a coloured spot, and a contractile vacuole. After a time they 
 come to rest, and fixing themselves by the mouth end, they lose their 
 cilia and envelope themselves in a membrane. The fixed end developes 
 into a root-like, colourless organ of attachment; the free end growing 
 into a club-shaped plantlet, through the cell, dividing into two by a cross 
 partition, and each of these again in two, and so further. Sexual repro- 
 duction arises through repeated bipartition .in each cell, from 8-32 and 
 more, smaller miorozoospores being produced. They have only two 
 cilia, and after a swarming for a time they conjugate laterally in pairs, 
 forming a zygospore, which attaches itself by the end corresponding to 
 the mouth of the miorozoospore. It grows very slowly, and finally 
 breaks up by the simultaneous division of its plasma into 2-14 swarm- 
 spores, which constitute the beginning of a new sexual generation. If 
 any of the microzoospores remain behind in the mother cells, they are 
 able, without copulation, to germinate and grow into independent plants 
 which may be seen singly or in groups projecting from the mother- 
 cells. 
 
 Kormiscia monilifozmis. IJKutz.) Babh. Alff. Eur. lli.,3Ql. 
 
 Pale green, more or less crispate, often mixed with other 
 Algse ; cells equal or a little shorter than their diameter ; cell- 
 membrane thick, colourless, somewhat lamellose, more or less 
 constricted at the septa. 
 
 Size. Cells •011-'014 mm. diam. 
 
 Ulothrix moniliformis, Kutz. Tab. Phy. ii., t. 88. Kirch. Alg. 
 Schl. p. 76. 
 
 In swamps, amongst Sphagnum, &c. 
 
 Plate LXX. fig. 1. Portions of threads of JSormiscia moniliformis 
 X 400 diam. 
 
 Kormiscia zonata. {Wei. Sf M.) Aresch. Ois. p. 12. 
 
 More or less bright green, mucous, two or three feet long, 
 often less, either floating or interwoven, sterile cells equal, or 
 half their diameter ; fructiferous cells usually a little longer 
 than broad ; cell-membrane thick, slightly constricted at the 
 septa. 
 
 Size. Cells •012--04 mm. ; macrozoospores •012--018x '01 
 •012 mm. ; microzoospores -OOS-'Ol x ■004-'007 ram. 
 
 Eabh. Alg. Eur. iii., 362. 
 
 Ulothrix zonata, Kutz. Tab. Phy. ii., t. 90, f. 2. Kirch. Alg. 
 Schl. p. 76. Dodel in Prings. Jahrb. t. x., pi. i.-viii. 
 
 liyngbya zonata, Hass. Alg. 220, t. 59, f. 1-6. 
 
 2 o 
 
180 
 
 NEMATOPHYCB^. 
 
 Conferva zonata, Web. & Mohr. in Ag. Syst. p. 90 ; Harv. 
 Man. 126. Eng. Fl. v., p. 351. Mack. Hib. 224. Dillw. 
 Conf. Syn. p. 41. Jobnst. Fl. Berw. ii., 254. Gray Arr. i., 
 311. 
 
 Conferva lubrica, Dillw. Conf. t. 47. 
 
 Conferva lucens, Eng. Bot. i., 1. 1655 ; ii., t. 2475. 
 
 In ditches, ponds, swamps, &c. 
 
 Plate LXIX. fig. a.\ ^. , . ,. ,... 
 
 ' z V Threads m ordmary condition, 
 
 ,, c. Portion of a thread with one maorozoospore 
 in each cell showing the red spot. 
 
 ,, d. Macrozoospores free with four cilia. 
 
 ,1 e. Macrozoospores in the resting state. 
 
 I, f. Macrozoospores germinating. 
 
 .1 g. Plantlet of six cells. 
 
 „ A. Threads with ripe microzoospores. 
 
 „ h2. With macro and microzoospores. 
 
 „ t. Microzoospores free with two cilia. 
 
 ,, k. Microzoospores in conjugation. 
 
 I, /. Eesting zygospores, the resnlt of the conjn- 
 gation of pairs of zoospores. 
 
 ,, m. Portion of threads with growing plantlets 
 arising from nncopnlated microzoospores 
 left behind in -the mother-cells. 
 
 „ n. Three healthy zygospores, 8 months and 9 
 days old. 
 
 „ 0. Zygospore contents differentiating. 
 
 I, p. „ in a later stage. 
 
 „ q. „ very large in two positions, show- 
 
 altogether 10 zoospores. 
 „ r. ,, with zoospores elongated. 
 
 Hotmiscia st[aalis. {KtUz.) Rabh. Alg. Hur. in., 363. 
 
 Yellowish-green, cells equal, or a little longer than their 
 diameter ; cell-membrane, rather thick. 
 
 var. catenaeformis. Eviz. 
 
 Kather thicker than in the typical form ; cells a little longer 
 than their diameter ; cell membrane thick, striate, manifestly 
 constricted at the septa. 
 
 Size. Cells •012--018 mm. diam. 
 
 Ulothrtx aqualis, Kutz. Tab. Phy. ii., t. 89, f. 1. Kirch. 
 Alg. Schl. 76. 
 
 Ulothrtx catenmformis, Kutz. Tab. Phy. ii., t. 89, f. 2. 
 
 In ditches and streams (mostly rapid) attached to aquatic 
 plants. 
 
 Plate LXX. fig. 2. Portions of threads of Sbrmiscia catenaformis 
 X 400 diam. 
 
ULOTRIOHBiE. 181 
 
 Hoimiscia speciosa. {Cwrm.') Ralh. Alg. Eur. ui., 363. 
 
 Dark green, 1-2 inches long, threads often ci'ispate, cells 2-4 
 times shorter than their diameter, fructiferous cells subglobose. 
 
 Size. Cells ■043--048 mm. diam. 
 
 Ulothrix speciosa, Kutz. Tab. Phy. ii., t. 93. 
 
 Lyngbya speciosa, Carm. Alg. App. ined. Hary. Phyc. 
 Britt. t. 186 B. Brit. Fl. ii., 371. Wyatt Alg. Danm. No. 
 196. 
 
 In brackish and fresh water. 
 
 Scarcely any good features whereby this can be distinguished from S. 
 bicolor. 
 
 Plate LXX. fig. 3. Portions of threads of Hormiscia speciosa X 400 
 diam. 
 
 Hozmiscia bicolor. (Eng. Bot. i., t. 2288.) 
 
 Bright green. Tufts very long, one foot or more ; articula- 
 tions two to three times shorter than their diameter, pectinate ; 
 cell membrane thick, distinctly lamellose. 
 
 Size. Cells "05 mm. diam. 
 
 Ulothrix crispa, Kutz. Tab. Phyc. ii., t. 92, f. 4. Kutz. Spec. 
 348. 
 
 Conferva bicolor, Eng. Bot. i., t. 2288. 
 
 Tyndandea bicolor, Eng. Bot. ii., t. 2508. Eng. Fl. v., 361. 
 
 Ulothrix bicolor, Ealfs, Alg. Exs. No. 13. 
 
 (/") Sphceroplea. crispa, Berk. Glean, t. 3, f. 1. Harv. Man. 
 144. 
 
 Lyngbya crispa, Jenner Fl. Tonb. Wells, 188. 
 
 In fresh water. 
 
 Whether this be really the Sphceroplea crispa of " Berkeley's Glean- 
 ings " seems open to reasonable doubt. 
 
 Plate LXX. fig. 7. Portion of thread of Hormiscia licolm- with 
 miorozoospores in lower cells X 400 diam. 
 
 Gen. 67. VtOTHRIX. Kutz. (1845.) 
 
 Threads articulate, simple ; articulations short, sometimes 
 shorter than their diameter, rarely a little longer ; cell mem- 
 brane thin, often very thin, Tsry rarely lamellose. Cell contents 
 effused, green, parietal, inclosing an amylaceous granule. 
 
 The slight differences between this genua and Hormiscia seems 
 scarcely sufficient to maintain them as distinct genera. 
 
182 
 
 XEMATOPHYCE^. 
 
 VIothxixToriaMlis. Kutz. Tab. Phyc. ii.,t.85,f.3. 
 
 Pale green ; cells equal or a little longer than their diameter, 
 rarely twice as long ; cell-contents at first always contracted in 
 a quadrate manner. 
 
 Size. Cells -OOS-'OO? mm. 
 
 Eabh. Alg. Eur. iii. 
 
 Ulothrix suhtilis, var. c. variabilis, Kirch, Alg. Sch. 77. 
 
 In ditches and slow streams. 
 
 The view entertained by Kirchner that this and U. tenerrima are 
 only varieties of Ulothrix suMilis is probably correct. 
 
 Plate LXX. fig. 4. Portions of threads of Ulothrix variabilis X 400 
 diam. 
 
 TTlothzix teneriima. Eutz. Tab. Phy. ii., t. 87, /. 1. 
 
 Pale green, or yellowish-green, hibricous ; cells mostly equal 
 in length and diameter, now and then a little shorter. 
 Size. Cells •007--01 mm. 
 Eabh. Alg. Eur. iii., 366. 
 Ulothrix suhtilis, var. e. tenei-rima, Kirch. Alg. Schl. p. 77. 
 
 In ditches, turbaries, &c. 
 
 Plats LXX.fig. 5. Portions of threads of Ulothrix tenerrima X 400 
 diam. 
 
 TTlothziz tenuis. Kutz. Tab. Phyc. ii., t. 89, /. 1, bis. 
 
 Dark green, attached, from half to two or three inches long, 
 mucous, cells equal or 2-4 times shorter than their diameter, 
 cell membrane thin, homogeneous. 
 
 Size. Cells •017--026mm. 
 
 Eabh. Alg. Eur. iii., 366. Kirch. Alg. Schl. p. 78. 
 
 In ditches and streamlets. 
 
 Plate LXX. fig. 6. Portions of threads of XSloihria tenuis X 400 
 diam. 
 
 Ulothzix (Hozmidinm) zadicans. Eutz. Tab. Phyc. ii., t. 95, f. 3. 
 
 Yellowish green, rather rigid, densely interwoven in a soft 
 velvety green stratum, cells either nearly equal or 2-3 times 
 shorter than their diameter. 
 
 Size. Cells -OOTS-'OOgS mm. 
 
 Eabh. Alg. Eur. iii., 367. Kirch. Alg. Schl. p. 77. 
 
 Hormidium miirale, Kutz. Phy. Germ. p. 193. 
 
 Lyngbya muralis, Ag. Syst. p. 74. Eng. Fi. v , 370. Has?. 
 Alg. 221, t. 59, f. 7. Eng. Bot. ii., t. 2522. Jenn. Tunb. 
 
ULOTEIOHEJL. 183 
 
 •Wells, 188. Harv. Man. 160. Johnst. Fl. Berw. ii., 259. 
 Mack. Hib. 238. 
 
 Conferva mitralis,'Di[\w. Conf. t. 7. Eng. Bot. i., t. 1554. 
 
 Humida muralis, Gray Arr. i., 282. 
 
 Oscillatoria muralis, Grev. Fl. Ed. 304. Fl. Dev. ii., 57. 
 Hook. Fl. Scot, ii., 79. 
 
 On the naked ground, rocks, walls, &c. 
 
 Kutzing has in some of his works applied to the terrestrial species of 
 Vlothrix the generic name of Rormidium, which is only of sectional 
 value. 
 
 Plate LXXI. fig. 1. Portions of threads of TJlothrix radicans 
 X 400. 
 
 Ulothzix (Hormidium) paxietina. {Vaiich.) Kutz, Tab. Phyc. Ii., 
 t. 97,/. 1. 
 
 Bright yellowish green, flexuous and interwoven, cells half 
 as long as broad, cell membrane thin, hyaline, homogeneous. 
 Size. Cells •009--016 mm. 
 
 Eabh. Alg. Eur. iii., 367. Kirch. Alg. Sohl. p. 78. 
 Hormidium parietinum, Kutz. Phyc. Germ. p. 193. 
 
 On walls, trunks, &c. 
 
 Plate LXXI. fig. 2. Portions of threads of Ulothrix parietina 
 X 400 diam. 
 
 Gen. 68. SCHIZOGONIUIH. Sutz. (1848.) 
 
 Threads as in Ulothrix, or in many places laterally connate 
 (duplicate or triplicate), or by cellular division in two directions 
 forming narrow flat bands, which are more or less crispate. 
 
 In 1861 Dr. Braxton Hicks indicated his belief that Scliieogoniwm was 
 only a condition of Vloikrix in which the threads had become connate, 
 of which Prasiola was only a frondose form. He says, " the whole of 
 these changes are so palpable, can be observed so constantly, and are, 
 at the same time, so simple in their relations to one another, that one 
 can scarcely imagine how they can have been separated, not only into 
 distinct species, bnt into diiferent families of Algae. Thns the linear 
 stage is called Zyngiya (Ulothrix) ; the early stage of collateral seg- 
 mentation, the Schixogonium ; the adult stage, the Prasiola ; while the 
 gonidial growth has been classed nnder Palmellacea." And again, 
 " the only real difference between the first two is, that whereas Lynghya 
 (Ulothrix) is a tube containing distinct cells within, which, when old 
 undergo collateral subdivision, to form a band of two, four, or eight 
 rows of cells, Schizogonium is a band of two or eight rows of cells, 
 which, when young was but a single row, contained in a tube, which 
 is only two different ways of stating the same facts. The comparison 
 of the last two is of the same kind. For as Prasiola, when old, is com- 
 posed of many rows of cells, but which arose from a single row, there 
 tanst have been a time in its life when it had t\Yo, four, or eight 
 rows, and thus have been a SchisogoHium, for there is no other 
 
184 
 
 NHMATOPHYOE^. 
 
 structural diffferenoe between the two." The whole of the commumca- 
 tion from whence the above is quoted is worthy of attentive perusal, 
 at least in so far as the relations between Uloihrite and Schizogonium 
 are concerned. It is entitled " On the Diamorphosis of Lyngiya, &o.," 
 in the " Quart. Journ. of Microscopical Science " for 1861, pp. 157-166. 
 
 Schizogonium muzale. EuU. Tab. Phyc. ii., t. 98, f. 1. 
 
 Dark green, forming a broadly expanded soft velvety 
 stratum, threads sometimes free, hei'e and there two or three 
 united, cells 2-4 times shorter than their diameter, pectinate, 
 often crowded, sometimes interrupted, cell membrane rather 
 thick, colourless, slightly undulated and constricted. 
 
 Size. Cells -OlS-'OlSmm. 
 
 Rabh. Aig. Eur. iii., 368. Kirch. Alg. Schl. 78. 
 
 On moist walls and naked ground. 
 
 Plate LXXI, fig, 3. Portions of threads of ScMssogonium murale 
 X 400 diam. 
 
 Familx VII. OHROOLEPIDB^. 
 
 Aerial algse, coloured golden yellow, orange or red-brown, 
 when dry often becoming greenish grey ; more or less fragrant 
 with the odour of violets. Threads articulate, variously 
 branched, cell membrane thick, or somewhat thick, firm, almost 
 cartilaginous, collected in minute tufts, or densely interwoven 
 in a thin or thick tomentose stratum. Cell contents oily or 
 granulose, either red, orange, or yellow brown, growing paler 
 after death. 
 
 Propagation by zoogonidia, produced in proper cells 
 (sporangia) which are terminal, or by prolification formed 
 laterally. Zoogonidia oblong-oval, furnished at one extremity 
 with two vibratile cilia. — Rabh. Alg. Eur. iii., 371. 
 
 Gen. 69. CHROOLEFVS. Ag. (1824.) 
 Characters the same as given above for the family. 
 
 There appears to us no occasion or justification for the substitution 
 of Trentepohlia for the above generic name as some authors have 
 done. 
 
 The following is an abstract of the process of reproduction, as ob- 
 served by Dr. Caspary. (Flora, Sept. 28,1858). "The apical cell of 
 the threads has often a globular or pulvinate appendage, of a highly 
 refractive nature, furnished with transverse wrinkles, and frequently 
 also with a protuberance at the top. The whole cavity of the cells is 
 filled with granular matter, mostly of a brownish red colour, but it 
 frequently happens that the inner granules only are brownish red, 
 
CHROOLEPIDB^. 185 
 
 whilsb the outer ones are green. The reddiah brovra granules seem 
 to be oil drops A great number of the threads terminate with a globose 
 much tliiokened cell, which subsequently beoomea the mother call of 
 the zoospores This mother cell ia rarely found in the middle of the 
 threads. Oooasionally, but still more rarely, the cell immediately under 
 the mother cell elongates itself sideways and upwards into a thread. 
 The mother cell of the zoospores, when it forma the terminal cell ot 
 the thread, bears a conical mass of gelatine, often ot considerable size, 
 which, however, is seldom on the crown of the cell, but usually at its 
 side. In those mother cells in which the zoospores are about to escape 
 a division of the contents into small oval cells is clearly perceptible, 
 and at the side, or near the top, the wall is extended into a short 
 papilla. The contents emerge in the form of a well defined vesicle, 
 with the zoospores penetrating through the ruptured papilla, some- 
 times, however, no vesicle is formed. A few moments after emerging 
 the vesicle bursts, doubtless by absorption of water, and the zoospores 
 swim about in every direction. The remnants of the vesicle are of a 
 gelatinous nature. The escape of the zoospores was observed from nine 
 in the morning till four ia the afternoon, and seems to depend not upon 
 the influence of light, but solely upon the effect of moistening with 
 water. The zoospores are very small, 'OOSo-'OOSS mm. They are 
 filled with reddish brown granular matter, the apex alone being free 
 and hyaline ; there are two cilia, about three or four times as long as 
 the spore. The apex with the cilia is directed forwards. They rotate 
 perpetually whilst swimming; their motion being so rapid as to prevent 
 a clear view of them, except when stopped by some obstacle, or when 
 their motion is becoming retarded. The cell is surrounded by a clear 
 highly refractive border looking like gelatine, but which may be only 
 an optical appearance. After continuing in motion for about an hour 
 the zoospores become sluggish, sink, become globular, elongate them- 
 selves, and shortly a division of the cell takea place by a tranaverse 
 septum. Some reddish brown granules usually remain behind in the 
 empty mother cell, and in the remnant of the vesicle. Oftentimes 
 some ziospores cannot emerge from the mother cell, and then they 
 sometimes germinate in it. These observations were made on a variety 
 of Chroolepus aureus. Quart. Journ. Micro. Science, vili. (1860), p. 
 159. 
 
 Chroolepus auieus , (Linn). Kutz. Tab. it., t. 93, 
 
 Golden red or orange. Threads either collected in small 
 tufts, or spreading in a soft silky stratum, sometimes intricately 
 and densely expanded and very much branched. Cells as long, 
 or two to three times as long as their diameter. 
 
 Size. Cells •01-'012 mm. diam. Zoosporangium "02 x 
 •03 mm. 
 
 Eng. Fl. T., p. 380. Eng. Bot. ii., t. 2528. Hary. Man. 
 189. Mack. Hib. 246. Rab. Alg. Eur. iii., 371. 
 
 Conferva aurea, Dillw. Conf. t. 35. 
 
 Byssus aurea, Eng. Bot. i., t. 212. Lightf. Fl. Scot. p. 1002. 
 Hull Br. Fl. 307. Relhan Cant. 446. Huds. Fl. Ang. 606. 
 Sibth. Ox. 338. Purton Midi. Fl. ii., 606. Ray. Syn. 56, No. 
 6. Abbot Bedf. 276. With. Arr. iv.,_ 144. 
 
 Ceramium aiireum, Hook. Fl. Scot, ii., 86. 
 
 Amphicomum aureum, Johnst. Fl. Berw. ii., 243. 
 
186 NEMATOPHVCB^. 
 
 Tientepohlia aiirea, Ag. Syst. p. 36. 
 
 Ectocarpxis aureus, Lyngb. Hydro. Dao. t. 44. Grer. Fl. 
 Ed. 315. 
 
 On walls, rocks, chips, bark, &c. 
 
 Plate LlLJLll. fig. 1. Portions of filaments X 400 a, zoospor- 
 angium ; h, zoospore ; c, same at rest ; d, germinating zoospore. 
 
 Chzoolepus odozatus. (Lyngb^ A.g. Syst. 35. 
 
 Stratum thin, rather tomentose, rufous-tawny (when dry 
 cinereous, becoming greenish). Threads and branches abbre- 
 viated, erect, parallel, flexuonsly curved, torulose ; cells equal 
 or twice as long as their diameter. 
 
 Size. Cells ■02-'025 mm. diam. 
 
 Eng. Fl. v., 381. Haw. Man. 190. Eabh. Alg. Eur. iii., 
 372. 
 
 Conferva odorata, Lyngb. Hydr. Dan. t. 57. Johnst. Fl. 
 Berw. ii., 245. 
 
 On the bark of various trees, especially of Birch and 
 Poplar. 
 
 Plate LXXII. fig. 2. Portion of thread of Cliroolepus odoratus x 400. 
 
 Chzoolepus lolithus. (Xinn.) Ag. Syst. p. Si. 
 
 Stratum thin, or a line thick, reddish-orange, glaucous or 
 dirty greenish when dry, threads and branches elongated, rather 
 dichotomous, variously curved, ascending ; cells one and a half 
 or three times as long as their diameter, in the upper portion 
 of the branches reaching to double that proportion. 
 
 Size. Cells ■025-'04 mm. diam. Zoosporangium '05 mm. 
 diam. 
 
 Eng. M. v., 380. Eng. Bot. ii., p. 189. Harv. Man. 189. 
 Mack. Hib. 246. Eabh. Alg. Eur. iii., 373. 
 
 Byssus lolithus, Linn. Spec. 1638. Hull. Br. Fl. 308. 
 
 Olivia violacea, Gray. Arr. i., 350. 
 
 Trentepohlia lolithus, WaUr. Comp. iv. 151. 
 
 On rocks, in moist places. 
 
 Plate LXXII. fig. 4. Portion of thread of CftrooZepus lolithus X 400; 
 fl, zoosporanginm x 400. 
 
 Chzoolepus ilicicolus, Eng. Bot- li., t. 2529. 
 
 Filaments erect, alternately branched, forming tufts of a 
 permanent tawny-yellow. Cells nearly as long as broad. 
 Size. Cells about -03 mm. diam. 
 Confei-va ilicicola, Eng. Bot. i., t. 1639. 
 
CHEOOLEPIDE^E. 187 
 
 Chroolepus aureus, Eng. Fl. y., 380, in part. 
 On Holly bark. 
 
 Included in Harvey's Manual (p. 189) under Chroolepus 
 aureus. Figured from the original specimen. 
 
 Plate LXXII. fig. 5. Portion of thread of Glwoolepus ilicicolus 
 X400. 
 
 Chroolepus lichenicolus. Ag. Syst. 34. 
 
 Tufts red-orange ; threads erect, tufted, alternately branched, 
 rigid ; cells slightly tumid, as long as broad. 
 
 Size. Cells '012 mm. diam. Zoosporangium about "015 
 mm. diam. 
 
 Eng. Fl.v., 381. Eng. Bot. ii. t., 2530. Hary. Man. 190. 
 Mack. Hib. 247. 
 
 Conferva lichenicola, Eng. Bot. i., t. 1609. Dillw. Conf. p. 
 56. 
 
 Chroolepus abietinum, Eabh. Alg. Eur. iii., 372, in part. 
 
 On Lichens and old trees. 
 
 Figured from the original specimens. 
 
 Plate ZXXII. fig. 3. Portion of thread of Chroolepus ahieUnuvi, 
 var. lichenicolus X 400. 
 
 Species Excluded. 
 
 Chroolepus Axnottii. Barv. Man. p. 191. 
 This is a fungus, Antennaria Arnottii, Berk in Herb. 
 
 Chzoolepus ebenea. Sarv. Man. p. 189. 
 
 Conferva ebenea, Dillw. Conf. t. 101. 
 Byssus nigra, Eng. Bot, i., t. 702. 
 
 Probably a species of Helminthosporium. 
 
 Chzoolepus melaenus . Carm. in Sarv. Man. p. 189. 
 Conferva melaena, Lyngb. Hydrot. 57. 
 Apparently a Torula. 
 
 Chzoolepus mesomelas. Carm. in Harv. Man. p. 189. 
 Torula mesomela, Carm. Alg. App. 
 
 We have seen no specimen, but it would appear from descrip- 
 tion to be Helminthosporium. 
 
 ■2 D 
 
188 SEMATOPHYCE^. 
 
 Family YIII. CH^TOPHORACB^. 
 
 Aqnatic or sTvamp-living alg£e, rarely terrestrial, moncecions 
 or dioecious. Articulate filaments various, often dichotomously 
 branched, not rarely fasciculately branched, accumulated in 
 tufts or pulvinules, nestling in a somewhat fluid or firm gela- 
 tinous mucus, or constituting, for the most part, a filamentose, 
 rarely a somewhat foliaceous thallus (formed from a single 
 stratum). 
 
 Propagation by oospores after sexual fecundation, or by zoo- 
 gonidia ; the latter produced singly, or by the division of the 
 cytioplasm, or contents of the sporangium, into eight or sixteen. 
 
 Gexus 70. laiCROTHAMNION. Nag. (18i9.) 
 
 Articulate filament dichotomously or trichotomously branched, 
 now and then very much branched, straight, with the terminal 
 cell obtuse, or nearly so, afterwards swollen, forming a sporan- 
 gium. Cell contents eifused, containing scattered amylaceous 
 granules. Propagation by zoogonidia. Plants microscopical, 
 more or less with a gelatinous investment. 
 
 Bliciothamnioii vexator. Cke. in Grevillea xi., p. 75. 
 
 Filaments erect, very slender, dichotomously branched, more 
 or less growing in tufts. Cells cylindrical, longer than broad, 
 not at all constricted at the joints, dissepiments scarcely visible. 
 Cell membrane thin, pellucid. 
 
 Size. Cells about -003 mm. diam. 
 
 Attached to aquatic plants in clear springs, &c. 
 
 A very delicate plant, first found by Mr. Tnmer in Yorkshire, and 
 since detected in several localities in England. Tery mnch more slender 
 than M. strictissimum. 
 
 Plate LXXIII. Jig 1. Filaments of Mtcrothamnion vexaior X 400. 
 a, tnfts of- plants natural size. 
 
 Genus 71. STXGEOCLONIUK. Kiite, (1843.) 
 
 Articulate threads simply branched, branches and branchlets 
 scattered, rarely approximate in a fascicvJate manner, acute at 
 the apex, sometimes attenuated into a colourless bristle, at times 
 extended very long, at other times furnished with shortly 
 subulate branches. Cell membrane very thin and hyaline, homo- 
 geneous. Cell contents, with the chlorophyll arranged in 
 transverse bands. 
 
OHJSTOPllORACB^. 189 
 
 Propagation by oospores or zoogonidia, the latter formed by 
 division (4-16) of the cell Contents, each zoospore furnished with 
 a red parietal spot and four vibratile cilia. 
 
 Stigeoclonium thezmale. Brawn in Kut%. Spec. p. 352. 
 
 Bright green, very much branched in a fasciculate manner, 
 somewhat creeping at the base, filaments and branches attenu- 
 ated upwards to the cuspidate apex, branchlets for the most 
 part alternate, rather remote, nearly erect or somewhat diver- 
 gent, setiform, joints variable in length, at the base of the 
 filaments equal or twice as long as the diameter, becoming 
 turgid, in the upper part of the branchlets 3-5 times as long as 
 the diameter ; chlorophyllose bands broad, sometimes effused. 
 
 Size. Cells -012 mm. 
 
 Eabh. Alg. Eur. iii., 376. Kutz. Tab. Phyc. iii., t. 2, f. 4. 
 Draparnaldia elongata, Hass. Alg. 123, t. 10, f. 3. Ann. 
 Nat. Hist. Aug. 1842, xi., p. 4. 
 
 In thermal springs, &c. 
 
 Hassall found this species on one occasion growing in a horse-trough. 
 It is sometimes mixed with other algae in ditches. 
 
 Plate LXXIII. fig. 2. Filament of Stigeoclonium thermale with 
 zoogonidia X 4:00 diam. 
 
 Stigeoclonium tenue. Ag. Syst. 57. 
 
 Bright green, lubricous ; filaments a little branched, branches 
 nearly simple, cells equal or 2-3 times as long as their diameter, 
 more or less distinctly constricted ; chlorophyllose bands 
 narrow ; branchlets scattered, shortened, nearly erect, subulate ; 
 cells at the base longer than broad, abbreviated towards the 
 apex. 
 
 Size. Cells -01 mm. diam. 
 
 Kutz. Tab. Phyc. iii., t. 3, f. 1. Kabh. Alg. Eur. iii., 377. 
 Kirch. Alg. Schles. p. 68. 
 
 Draparnaldia tenuis, Eng. PI. v., 388. Eng. Bot. ii., p. 199. 
 Harv. Man. 122. Mack. Hib. 222. Hass. Alg. 123, t. 11, 
 f. 2. 
 
 Conferva luhrica, Dillw. Conf. t. 57. Grev. Fl. Ed. 318. 
 Hook. Fl. Scot, ii., 82. Gray Arr. i., 303. 
 
 Conferva exigua, Dillw. Conf. t. 2 (young). 
 
 In streams and ditches. 
 
 " At first the filaments are enclosed, in the manner of a Chatophm'a, 
 in a common, somewhat definite gelatine ; afterwards, on its bursting, 
 they issue from it like a Conferva, but are at all times very gelatinous." 
 — Harvey. 
 
 Plate LXXIII. Jig. 3. Filament of Stigeoclonium tenue X 400 diam. 
 
190 NKMATOPHYCE^. 
 
 Stigeoclonium piotensum. {Dillw.) Kutz. Tab. Phyc.iu„t.8,f. 2. 
 
 Pale green, csespitose, slender ; filaments and branches long 
 drawn out ; cells almost cylindrical, equal or twice as long as 
 their diameter ; terminal cell extended into a colourless bristle ; 
 branches usually scattered, rarely in pairs, with the extremities 
 cuspidate, piliferous. 
 
 Size. Cells '015 mm. diam. 
 
 Eabh. Alg. Eur. iii., 378. 
 
 Draparnaldia condensata, Hass. Alg. 122, t. 11, f. 1. Ann. 
 Nat. Hist, xi., 429. 
 
 Conferva protensa, DUlw. Conf. t. 67. Gray. Arr. i., 303. 
 
 In slow streams. 
 
 Jflate LXXIV. fig. 1. Filament of Stigeoclonium protensum. a, 
 zoospores X 400 diam. ; b, branchlet of form called S. irregudare x 
 400 diam. 
 
 Stigeoclonium nanum. (JHllw.) Kutz. Spec. p. 352. 
 
 Filaments alternately branched ; branches abbreviated, a 
 little attenuated upwards, obtuse, not piliferous ; cells equal or 
 a little shorter than their diameter, in the upper part equal. 
 
 Size. Cells "008 mm. diam. 
 
 Eabh. Alg, Eur. iii., 380. 
 
 Drapamaldia nana, Hass. Alg. 124, t. 10, f. 3. 
 Draparnaldia sparsa, Hass. Ann. Nat. Hist, xi., 428. 
 Conferva nana, Dillw. Conf. t. 30. 
 
 In streams (the Wye). 
 
 The following are DiEwyn's remarks on this species : — •" The minnte- 
 ness of the filaments, which in length seldom mnch exceeded a line, 
 prevented me from ascertaining their natnre so fully as I conld have 
 wished. Their colour is pale brown, tinged with green, sub-diaphanous 
 under the microscope. They appear to consist of a single stem, beset 
 at uncertain distances with alternate branches, which are again clothed 
 with short, simple, solitary ramuli, placed at small distances from each 
 other, most commonly alternate, although sometimes two or more 
 together are disposed on the same side. All of them are finely acumi- 
 nated ; the dissepiments are very apparent, and divide the filament into 
 joints, all of equal size, of which the length is about double the thick- 
 ness. To the naked eye this plant appears, when taken from the water, 
 like a mere mass of decaying vegetable matter. Its extreme minuteness 
 might fairly induce a suspicion whether it is in reality anything more 
 than the seedling of some known Conferva. It adheres to either glass 
 or paper." 
 
 Plate LXXIV. jig. 2. Filament of Stigeoclonium nanum X 400 
 diam., figured from Dillwyn's original specimen. 
 
CIIJDTOI'HORAOBJS. 191 
 
 Stigeoclonium fastigiatum. {Malfs.) Kutz. Tab. Phyo. iii., 
 t. 8, /. 1. 
 
 Pale green, small, thread very much branched, fastigiate, 
 radiately disposed, mucous, upper branches alternate, fastigiate, 
 moniliform, somewhat pinnate, a little spreading, extended at 
 the apex in a long bristle ; cells of the filament three times as 
 long as broad, the branches equal or twice as long, swollen, 
 constricted at the joints. 
 
 Size. Cells -012 mm. diam. 
 
 Rabh. Alg. Eur. iii., 380. 
 
 Chcetophora fastigiata, Ralfs. Alg. Exs., No. 9. 
 
 Attached to aquatic plants. 
 
 Plate LXXiy. Jiff. 3. Filament of Stigeoclonium fastigiatum X 
 400 diam. 
 
 Genus 72. DR.APARNALSIA. Ag. (1824.) 
 
 Articulate thread simply branched, formed of large cells, for 
 the most part hyaline, with a broad chlorophyllose band, always 
 sterile ; more or less densely furnished with penicellate fascicu- 
 late branchlets, alternate or opposite, composed of smaller 
 fertile cells. Terminal cells of all the branches empty, hyaline 
 and sterile, more or less elongated into a bristle. 
 
 Propagation by resting spores or zoogonidia. 
 
 Dzapaznaldia glomerata. Ag. Syst. p. 59. 
 
 Filaments and primary branches colourless, or nearly so ; 
 "lower cells equal, or a little shorter than their diameter, dis- 
 tinctly constricted at the joints ; chlorophyllose bands narrow, 
 pale green, primary branches spreading at right angles, some- 
 times opposite ; fascicles of the branches crowded, alternate or 
 opposite, densely branched, obtuse, oval. 
 
 SiZB. Cells of main thread -035 mm., of fascicles -008 mm. 
 
 Eng. Fl. v., 888. Jenner Tunb. Wells 176. Bng. Bot. ii., 
 t. 2545. Harr. Man. 121. Grev. Fl. Ed. 321. Mack. Hib. 
 222. Flor. Dev. ii., 50. Hook. Fl. Scot, ii., 77. Gray. Arr. 
 i., 302. Hass. Alg. 120, t. 13, f. 1. Kabh. Alg. Eur. iii., 381. 
 Kirch. Alg. Schles. p. 67. Kutz. Tab. Phyc. iii., t. 12. 
 
 Conferva muiabilis, Dillw. Conf. t. 12. Eng. Bot. i., t. 
 1746. 
 
 Batrachospermum conglomeraium, Vauch. Conf. t. 12, f. 1. 
 
 In clear pools or slow streams. 
 
192 yEMATOPHYOB^. 
 
 Very common, and well known. Variable in the size, number, and 
 disposition of the fascicles. 
 
 Plate LXXF. fig. 1. Portion of filament of Drapamaldia glomerata 
 X 400 diam. Fig. 2, portion of filament of the variety distans X 400 
 diam. 
 
 In 1857 Dr. Braxton Hicks first described in the "Jonrnal of the 
 Linnean Society" (Vol. i., p. 192) what he believed to be a new species of 
 Drapamaldia under the name of Ih-apamaldia cruciata, of which we 
 know nothing except from his description and figures, from which we 
 are disposed to regard it as a variety of Drapamaldia glomerata. It 
 was first found in the New Forest, and was more fully illustrated in the 
 " Quarterly Journal of Microscopical Science " (Vol. ix., 1869, p. 383, 
 pi. xix.). " Nothing," he says, "is more remarkable than the direction 
 taken by the branches, which diverge strictly at right angles to the 
 stem. Even the lesser kind, called tufts, and their branchlets, pass off 
 in this way, and as four generally spring from the same joint, there is 
 a cruciate arrangement in every part." 
 
 The following is given as its description : — " Frond 3-4 inches long. 
 Light green colour, not so green as J5. glomerata and D. plumosa, 
 possessing a flocculent appearance when in water, and highly mucous 
 when cut of water. Every portion is surrounded by a distinct layer of 
 transparent mucous, extending on each side to the distance of three 
 diameters of the included ramulus. This is most easily seen after two 
 days, when extraneous matter adheres to the mucous. The main filament 
 is composed of cells very slightly inflated, 3-4 times longer than wide, 
 about ^^th of an inch wide, delicately fasciated. Primary ramuli pro- 
 ceeding at right angles, chiefly in whorls of four, from the main 
 filament, with an interval of 50-60 cells. The sub-ramuli also proceed 
 in the same way from the primary ramuli, giving the plant a cruciate 
 appearance. The cells of the ramuli as wide as long, the larger fasciated, 
 the smaller quite filled with green chlorophyll. The interspace of 50-60 
 cells of main filament being great, to the naked eye it appears 
 nearly bare, but by higher magnifying powers small tufts, like 
 those terminating the sub-ramuli, appear at about every ten 
 cells; some larger, and approaching somewhat the sub-ramnli, 
 while the others are very simple. The larger terminal and lateral 
 tufts have a pyramidal form, and from all their divisions pro- 
 ceeding at right angles it appears much like a fir tree. All 
 the ultimate tufts bear cilia, as in the other I>raparnaldi(B, but of 
 extreme length and tenuity. From the 1-3 basal cells of the ramuli 
 often roots spring, coiling themselves round the main filament, and 
 even spreading away from it, and sometimes the free point becomes 
 converted into a tuft, hke those on the main filament. The smaller 
 tufts at times possess them. When the plant is mature the ramuli 
 disengage themselves, and can be seen floating about with their roots, 
 probably ready to attach themselves to any suitable object, and so 
 become separate plants. Zoospores not so large as in D. glomerata, 
 being oval, and about 0004 X '0003 inch. A whole tuft undergoes, the 
 process simultaneously." 
 
 " It can easily be distinguished from JD. plumosa and J), glomerata 
 by the divisions diverging at right angles, and in whorls of chiefly 
 four (giving the cruciate appearance), the perceptible mucous gheath, 
 exceeding delicacy of the cilia, extreme tendency to give out radicles, 
 the nearly equal width of tlie main cells, as also their greater length. 
 The fir tree-like form of the tufts are so unlike the flexible shape of 
 the other species." 
 
 A comparison of the plate given with the description we are bound to 
 say does not completely bear out all the distinctions. 
 
OHJETOPHOEACBJi;. 193 
 
 Drapaxnaldia plumosa. (Va-uoh.) Ag. Syst. p. 5S. 
 
 Threads and primary branches hyaline, cells equal or shorter 
 than their diameter, rarely a little longer, a little, or but scarcely 
 constricted at the joints, chlorophyllose bands narrow, bright 
 green, lower cells of the branches equal or almost twice as long 
 as their diameter, upper cells cylindrical, attenuated, 2-5 times 
 as long as broad, sometimes not piliterous, fascicles of the branches 
 densely branched, elongated, with an acutely lanceolate outline, 
 erect, somewhat appressed. 
 
 Size. Cells of main thread -045 mm., of fascicles '008 mm. 
 
 Eng. Fl. v., 388. Eng. Bot. ii., t. 2544. Harv. Man. 121. 
 Johnst. Fl. Berw. ii., 258. Mack. Hib. 222. Flor. Der. ii., 50. 
 Hook. Fl. Scot, ii., 77. Gray Arr. i., 303. Hass. Alg.121, t. 
 12, f. 1. Eab. Alg. Eur. iii., 382. Kirch. Alg. Schles. p. 67. 
 Kutz. Tab. Phyc. iii., t. 14. 
 
 Conferva lubrica, Eng. Bot. i., t. 2087. 
 
 In slow streams or pools. 
 
 Much less common than the preceding speoie.s. 
 
 Plate LXXVI. fig. 1. Portion of filament of Draparnaldia plumosa, 
 X 400. Fig. 2. Portion of filament of the variety pulchella x 400. 
 
 Genus 73. CHAITOPHORA. Sclirank. (1789.) 
 
 Articulate filaments, with the primary branches radiately dis- 
 posed, composed of elongated vegetative cells, with chlorophyll 
 bands as in Draparnaldia and Stigeoclonium ; divided upwards 
 into numerous branchlets, which are shortly artoculated, the 
 ultimate joint attenuated, often empty, scarcely or not at all 
 lengthened into a thread, ultimate branchlets in more or less 
 crowded fascicles, involved in a firm gelatinous, coriaceous, or 
 hard mass, of a globose or subglobose, or plane, expanded, 
 variously lobed form. Propagation the same as in the preced- 
 ing genera. 
 
 Cheetophora pisiformis. (iJot/t.) Ag. Syst.p. 27. 
 
 Thallus globose, about the size of a pea, often smaller (now 
 and then as large as a cherry), bright green, even, shining, 
 sometimes aggregated, not rarely confluent. 
 
 Size. Cells •006--009 mm., of branches -006 mm. 
 
 Hass. Alg. 128, t. ix., f. 5, 6. Kutz. Tab. Phy. iii., t. 18, 
 fig. 3. Grev. Sc. Crypt. Fl.,t. 150. Eabh. Alg. Eur. iii., 383. 
 Kirch. Alg. Schl. p. 69. Eng. Fl. v., 389. Harv. Man. 123. 
 Berk. Glean, t. 1, f. 1. 
 
194 
 
 NEMATOPHYCEJE . 
 
 Ulvapisiformis, Huds. Fl. Aug. 572. With Ait., iv. 120. 
 Chcetopliora elegans, Lyngb. Hydro, t. 65. 
 
 On submerged plants. 
 
 J'late LXXVII. fig. 1. Plants of Chcetophora pisiformis, natural 
 size, and filaments X 400. 
 
 Chstophora tuberculosa. (Soth.) Ag. Si/st. 
 
 Thallus subglobose, tbe size of a cbeny, bright or pale green, 
 surface tuberculose, elastic, fascicles of branches very dense, 
 lower articulations cylindrical, the upper swollen, extremities 
 cuspidate, sharp pointed, rarely hair-like. 
 
 Size. Cells •009--012 mm., of branches •008--01 mm. 
 
 Harv. Man. p. 122. Hass. Alg. 126, t. 9, f. 7, 8. Kntz. 
 Tab. Phyc. iii., t. 19, f. 1. Eabh. Alg. Eur. iii., 383. Eng. 
 Fl. v., 389. Jenner Tunb. Wells p. 178. Eng. Bet. ii., t. 
 2547. Johnst. Fl. Berw. ii., 260. Mack. ffib. 223. Hook. 
 Scot, ii., 76. Kirch. Alg. Schles. p. 69. 
 
 Rivularia tuberculosa, Eng. Bot. i., 2366. 
 
 In clear water. 
 
 Plate LXXl'III. fig. 1. a, plant of ChcBtopliora tuberculosa, natural 
 size, b, filaments of same X 400 diam. 
 
 Chstophora elegans. (Both.) A^. Syst. 
 
 Thallus the size of a pea or a cherry, pale green, surface 
 even, elastic, soft, now and then becoming hard, fascicles of 
 branches lax, rather flaccid, extremities shortly cuspidate, often 
 terminating in a hair. 
 
 Size. Cells •007--009 mm., of branches ■005--007 mm. 
 
 Kutz. Tab. Phyc. iii., t. 20, f. 1. Eabh. Alg. Eur. iii., 384. 
 Kirch. Alg. Schl. p. 69. Eng. Fl. v., 389. Jenner Tunb. 
 Wells 178. Mack. Hib. 223. Harv. Man. 122. Grev. Fl. 
 Ed. p. 321. Hass. Alg. 127, t. 9, f. 3, 4. 
 
 Rivularia elegans, Eng. Bot. i., t. 1797. Purton Mid. Fl. 
 ii., 618. 
 
 In clear water, attached to submerged plants. 
 
 Paler in colonr, and more hyaline and gelatinous than C. pisiformis. 
 Plate LXXVII. Jig. 2. a, plants of Chtetophora elegans natural 
 size, b, zoogonidia. c, filament X 400. 
 
 Chsetophoza endivaefolia, Ag. Syst. p. 28. 
 
 Thallus linear, flattened, i-1 inch, now and then elongated, 
 bright or dark green, dichotomously laciniate (sometimes with 
 the habit of Biccia flttitans), threads and primary branches 
 mostly colourless, here and there with green zones, parallel 5 
 
CH^TOPHORACE^. 195 
 
 fascicles of branches lateral, more or less dense, spreading arti- 
 culations more or less swollen, nearly equal in length and 
 diameter, constricted at the joints, cell contents granulose, 
 effused. 
 
 Size. Cells •01--015 mm., of branches -OOS-'Oll mm. 
 
 Kutz. Tab. Phy. in., t. 21, f. 2. Rabh. Alg. Eur. iii., 385. 
 Kirch. Alg. Schl. p. 70. Eng. PI. v., 389. Eng. Bot. ii., t. 
 2546. Hary. Man. p. 122. Johnst. Fl. Berw. ii., 261. Mack. 
 Hib. p. 222. Hook. Fl. Scot, ii., p. 76. Hass. Alg. 125, t. 9, 
 f. 1, 2. 
 
 Batrachospermum fasoiculatum, Vauch. Conf. p. 116, t. 13. 
 
 Ulva incrassata, Eng. Bot. i., t. 967. Huds. Fl. Ang. ii,, 
 572. With. Arr.iv.,' 124. 
 
 Conferva gelatinosa Damce cornu, Ray Syn. p. 60. 
 
 Tremella gelatinosa Dama conwMra, Dill. Muse. 51, 1. 10, f. 10. 
 
 Rivularia incrassata, Purton Mid. Fl. iii., p. 179. 
 
 Myriodactylon endivmfolium, Gray Arr. i., 302-. 
 
 In ditches, &o. 
 
 Exceedingly variable in the form of the thallus, and hence divided 
 into 7 or 8 varieties. 
 
 Plate LXXVIII. fig. 2. a, plants of Cliatoplwra endivcefilia, 
 natural size, i, portion of filament X 400 diam. 
 
 Chsetophora punctifozmis. Kutii. Tab. Phyc. iii., p. 4, t. 18, /. 2. 
 
 Echinella articulata, Eng. Bot. ii., t. 2555. 
 
 Conferva echtnata, Eng. Bot. i., t. 1378. 
 
 Assuming that Mr. W. Phillips (Grevillea ix., p. 5) is 
 correct in the presence of globose basal spores, this will have 
 to find a place in Rivularia, and not in Chcetophora. 
 
 Genus 74. COLEOCHJETE. .Br^J. (1844.) 
 Articulated filaments branched, either united in a pulvinule, 
 or little cushion, or expanded in a flat, somewhat disc-shaped 
 parenchymatous thallus ; cells oblong, more or less dilated in 
 front, sometimes bearing from the back or upper surface a 
 hyaline bristle, which is sheathed at its base. 
 
 Propagation by oospores resulting from sexual fertilization, 
 and by zoogonidia. Zoogonidia single in the fructiferous cells, 
 either globose or broadly oval, furnished with two vibratile cilia. 
 
 The Coleochaetese are small discoid Algse, from 1 to 2 mm. in diam., 
 bright green colour, constructed of branched rows of cells. They are 
 found attached to submerged plants in stagnant or slow-moving streams, 
 and form circular, closely-pressed discs. The chlorophyll is in parietal 
 plates or large granules. Some of the cells bear colourless erect bristles 
 fixed at the base in narrow sheaths. 
 
 2 E 
 
1 96 NEMATOPHYCBiB. 
 
 Reproduction takes place by means of asexual zoogonidia, and sexu- 
 ally produced oospores. The latter do not at once produce new plants, 
 but several zoospores. The zoospores, which are developed in the early 
 part of the year from resting-spores of the previous year, produce only 
 asexual plants which only form zoogonidia. After a series of asexual 
 generations, of variable length, a sexual generation arises, which accord- 
 ing to the species is moucecious or dioecious. Fertilization produces 
 one oospore in the oogonium, which developes into a reproductive body, 
 from the cells of which zoospores proceed in the next period of vegeta- 
 tion. Zoogonidia may originate in all the vegetative cells of the Coleo- 
 chaetea3, and are always formed from the entire contents of the mother- 
 cell, escaping through a round hole in the cell wall. 
 
 " In C. pvlvinata the terminal cell of a branch swells up, and at the 
 same time elongates into a narrow sac, which then opens, and exudes a 
 colourless mucilage. The protoplasm of the swollen part, which con- 
 tains chlorophyll, forms the oospore, in which a nucleus is visible. The 
 antheridia are formed at the same time in adjoining cells, two or three 
 protuberances growing out, which become separated by septa ; each of 
 the cells thus formed, which have somewhat the shape of a flask, is an 
 antheridinm ; its entire contents form an antherozoid of oval shape 
 with 2 cilia, which is endowed with motion like a zoogonidium ; its 
 entrance into the oogonium has not yet been observed. The effect of a 
 fertilization is seen in that the contents of the carpogonium become 
 surrounded with a proper membrane and form the oospore." 
 
 Coleochsete soluta. Prings. Jahrb. t. 1, /. 2. 
 
 Threads radiating from a common centre, furcately branched, 
 of equal length, closely packed side by side, prostrate, but not 
 connate, forming an orbicular disc. Cells one and a-half to 
 three times as long as broad, oogonia placed before the terminal 
 cells, globose, corticate. 
 
 Size. Cells -025 mm. 
 
 Eabh. Alg. Eur. iii., 389. Kirch. Alg. Schles. p. 50. 
 
 Attached to aquatic plants. 
 
 Plate LXXVIII. fig. 3. Plant of Goleochmte soluta X 400. a, Oogo- 
 nium X 250 diam. 
 
 Coleocheete scutata. B7-eb. Ann. Soi. Nat, 1844, p. 29, t. 2. 
 
 Filaments and their branches radiating from the centre, very 
 densely connate in one stratum, forming a kind of parenchy- 
 matous orbicular disc ; cells quadrangular, nearly equal or twice 
 as long, oogonia subglobose, peripherical, corticate above, naked 
 below. 
 
 Size. Cells •02--022 mm. 
 
 Eabh. Alg. Eur. iii., 390. Hass. Alg. 217, t. 77, f. 6. 
 Prings. Jahrb. t. i., f. 4 ; t iii., f. 3, 4. 
 
 Phyllactidium setigerum, Kutz. Tab. Phyc. iv. 
 
 On aquatic plants. 
 
 Plate LXXIX. Coleochwte scutata. a, plant X 200. b, portion with 
 oogonia. «, portion with antheridia cells. A, zoospore, active and at 
 rest, e, development of young plants. 
 
CHiETOPHORACB^. 197 
 
 Coleochaete oxbiculaxis. Prings. Jahrb. t. 1, /. 5. 
 
 Disc orbicular, parenchymatous, formed from one stratum of 
 ■cells, bright green, cells oblong-quadrangular when old, by 
 pressure becoming often polygonal, usually twice as long as 
 liroad. Oogonia oval, peripherical, mostly naked. 
 
 Size. Cells •012--017 mm. 
 
 Eabh. Alg. Eur. iii., 390. Kirch. Alg. Schles. p. 50. 
 
 Phyllactidium pulchellum, Kutz. Tab. Phyc. iv. 
 
 On aquatic plants; 
 
 Plate LXXX. jig. 1. a, plant X 200. 6, portion with oogonia, after 
 Pringsheim X 250. 
 
 Genus 76. AFHANOCKJETE. Braun. (1847.) 
 
 Articulate threads prostrate, somewhat creeping, sometimes 
 more or less united in an irregular stratum. Branches decum- 
 bent or ascending, cells bearing on their apax or back, often a 
 long bristle which has no sheath at the base. Propagation by 
 zoogonidia. Oogonia at present unknown. 
 
 Aphanochaete zepens. Sraun JRejuv. p. 184. 
 
 Filaments and branches procumbent, adpressed ; cells slightly 
 swollen, of equal diameter in both directions, supporting an 
 indistinctly articulated bristle. 
 
 Size. Cells •005--01 mm. 
 
 Kabh. Alg. Eur. iii., 391. Kirch. Alg. Schles. p. 71. 
 
 On Cladophora flavescens, and other Algse. 
 Plate LXXX. fig. 3. Plant of Aphanochcete repens X 400. 
 
 Aphanocheete hystzix. (Thw.) Mdbh. Alg. Eur. in. 391. 
 
 Filaments and their branches radiating, procumbent, ad- 
 pressed ; more or less connate, in a pale green irregular discoid 
 thallus. Cells somewhat cylindrical, produced at the apex into 
 a long bristle, which is not articulated. 
 
 Size. Cells '01 mm. diam. 
 
 Ochlochcete hystrix, Thwaites in Harv. Phyc. Britt. t. 226. 
 
 On aquatic plants in brackish ditches. 
 
 Perhaps scarcely deserving a place here, as it is almost, if not quite, 
 a marine species. 
 
 Plate LXXX. fig. 2. a, plant of Aphanochcete hysirix, slightly 
 .magnified, b, portion more highly magnified, after Harvey. 
 
198 
 
 APPENDIX 
 
 TO OHLOEOPHYLLOPHYOE^. 
 
 In the form of an Appendix we shall here enumerate a few 
 species, of doubtful position, which are not known with suflfioient 
 exactitude to be recorded in systematic order, although their 
 aflfinities appear to be with the Algae. The SaprolegniecB are 
 not included, because they are now generally acknowledged as 
 Fungi. The genus Syncliitrium also appears to be more nearly 
 related to Protomyces, amongst Fungi, than to Algae. 
 
 Family. OHYTRIDIE^. 
 
 Plants for the most part aquatic, parasitic, epiphytal or endo- 
 phytal, occasionally epizoic, very rarely terrestrial, one or two- 
 celled. Cells vesiculose, single or gregarious, either innate in 
 the fostering plant, or penetrating its membrane ; furnished 
 with radicles at the base, or destitute of them ; now and then 
 numerous and densely aggregated, involved in a common mem- 
 brane, nestling in the parenchyma of terrestrial plants, and form- 
 ing pustules. Protoplasm mucilaginous, usually colourless, 
 sometimes coloured. Antheridia not yet observed. Propaga- 
 tion by oospores or zoogonidia. 
 
 Some authors have united the majority of the species under the one 
 genus Chytridium, whilst others have distributed them over several 
 genera, as Chytridium, Plilyctidium, Rhywphidiwm,, Olpidiwm, and 
 Rhizidium, but apparently without good reason. 
 
 Genus 76. CHYTRIDIUM. Brmm. (1851). 
 
 Cells globose or somewhat pear-shaped, operculate above, the 
 root-like base usually innate in various algae, penetrating the 
 membrane of their cells. 
 
 Zoogonidia very numerous, globose, with a nucleus, bearing a 
 single very long cilium, escaping through the orifice of the cell 
 caused by the falling away of the operculum. 
 
0HYTR1DIB.S;. 199 
 
 " The Chytridia form a genus of unicellular, parasitical Algse, or, if it 
 be preferred, of aquatic Fungi, related to Saprolegnia about as much as 
 Ascidium is to Bryopsis. The entire plant is composed of a single balloon- 
 shaped cell, which penetrates into the Algae upon which it grows, by a 
 more or less developed root-lilie base. The inflated portion of the cell is 
 filled with colourless mucilage, from which are formed, not through suc- 
 cessive division, but by a simultaneous process, very numerous small 
 globular germ-cells, which exhibit a sharply-defined darker nucleus in the 
 interior, and possess a single very long cilium. From their want of 
 colour and the activity of their motion these gonidia resemble the most 
 minute monads. Their extrusion occurs either through the casting off of 
 a lid or through mere tearing of a nipple-shaped point. Of fifteen different 
 species which I have observed in the vicinity of Freiburg, Chytridium 
 olla is the largest, and at the same time exhibits the lid-like dehiscence 
 most beautifully. It grows on the anterior wrinkled end of the bulging 
 parent-cells of the spores of (Edogoaium Landsboroughii, the root pene- 
 trating into the folds and attaching itself to the spore. The free Inflated 
 portion of the cell is ovate, with the lid somewhat thrown up at the 
 edges, and apiculated like a short nipple in the middle. The germ-cells 
 are about '003 mm. diam." — Brawn, Sejuvenescence, pp. 1 86 note. 
 
 See also Braun, " Ueber Chytridium " (Berlin, 1856} ; Cohn in " Hed- 
 wigia," 1865, p. 170 ; Nowakowski " Beitrag zur Kenntniss der Chytri. 
 diaceen ' (Breslau, 1876). 
 
 Chytzidium acuminatum. Braun Chytr. p. 28, t. 1, /. 11. 
 
 Cells mucli smaller than in Chytridium olla, ovate-pyriform ; 
 operculum acuminate. 
 
 Size. Cells -016 mm. long. 
 Eabh. Alg. Eur. iii., p. 277. 
 
 Parasitic on species of CEdogonium, 
 
 Plate LXXXI. fig. 1. Chytridium acuminatum parasitic upon (Edo- 
 gomum SotMi X 400 diam. 
 
 Genus 77. RHIZOPKYDIUIffi. Schenh. (1858.) 
 
 Cells globose, ovate, or broadly clavate, -with 2, 3, or more 
 scattered orifices, more or less elongated into a neck, furnished 
 ■with, or destitute of, distinct radicles at the base. 
 
 Rhizophydium Bazkexianum. (Archer.) Sabh. Alg. Eur. in. 281. 
 
 Cells much depressed, 3 or 4 lobed,the lobes broadly rounded ; 
 upper surface of the cell concave, bearing at the centre a ver- 
 tical hyaline, very slender, terete, minutely capitate process ; 
 cell contents mainly confined to the centre, leaving the ends of 
 the lobes empty ; zoospores making their exit through the 
 opened apices of the lobes. 
 
 Chytridium Barkerianum, Archer in Quart. Journ. Micr. Sci. 
 1867, p. 89. 
 
 Parasitic on Zygnema. Callery Bog (Ireland). 
 
 We have seen no specimens, and are not aware of any figure extant, or 
 of any dimensions having been recorded. 
 
 2 F 
 
200 CHYTEIDIE^. 
 
 Gbnus 78. OLFIDIUia. Braun. (1856.) 
 
 Cells globose or subglobose, parasitic, epiphytal, or endo- 
 phytal, not operculate, nor rooting ; mouth Tertical, elongated 
 into a cylindrical tube. 
 
 Olpidium endogenum. BroAin Chytrid. No. 20, t. Y., f. 21. 
 
 Parasitic in the interior of plants, usually gregarious, de- 
 pressedly globose, extended at the apex into a tubular neck, 
 which is globosely dilated in the middle ; perforating the mem- 
 brane of its host, is extended beyond with a funnel-shaped 
 mouth. 
 
 Size. Cells about -024 mm. diam. 
 
 Olpidium intestinum (Braun), Rabh. Alg. Eur. iii., 283. 
 
 Parasitic in Closterium, Vancheria, &c. 
 
 This appears to be the species figured by Henfrey as occurring within 
 the cells of EremospJusra viridis in " Quart. Jonrn. Micr. Sci." vii. (1859), 
 t. 3, figs. 11, 12. Also by Garter in Spirogyra, in " Annals of Natural 
 History," Znd Series, Vol, xvii. (1856), t. 9, figs. 9 and 10. 
 
 Plate LXX.X1. Jig. 2. Olpidium endogenum parasitic in Closterium 
 lunula X 4:00. 
 
 Olpidium ampullaceum, {Braun.) Babh. Alg. Eur. ill., 282. 
 
 Epiphytal, gregarious, globose, small, sessile, rarely pedicel- 
 late, tubular, mouth erect, cylindrical, about as long as the cell, 
 terminating in a conical apiculus. 
 
 Size. Cells "0065 mm. diam. 
 
 Chytridium ampullaceum, Braun Chytrid., p. 66, t. 5, f. 24-27. 
 
 Parasitic on various algsB. 
 
 It was probably this, or a closely-allied species, which was figured by 
 Henfrey as parasitic on Eremosphcera viridis in " Quart. Joutn. Micr. 
 Sci." vii. (1859), t. 3, f. 13, 14. 
 
 Plate LXXXI. Jig. 3. Olpidium ampvMaceum parasitic on Mougeotia 
 X 400 ; 3a, individual further magnified. Fig. 4, allied species x 400. 
 
 Genus 79. SYNCHITRIUK. D.By. 4- Wor. (1863.) 
 
 Thallns multiform. Cells (sporangia of some authors) often 
 numerous and aggregated, closely involved in a common mem- 
 brane, forming sori, filled with delicately granular orange con- 
 tents. Zoogonidia globose, rarely oval or oblong, with a lateral 
 orange-red nucleus, bearing a single (rarely 2) very long cilium. 
 
 Inhabiting the substance of plants, with the habit of Ure- 
 dines, but without mycelium. 
 
0HYTRIDIEJ5. 201 
 
 Synchitrium Tarazaci. B. By. ^ War. BericM. der Naturf. Oes. 
 Freilurg iii., t. 2, /. 1-7. 
 
 Orange warts, about -5 mm. diam., prominent on both sur- 
 faces of the leaf, scattered or crowded. During summer each 
 wart contains a mass of crowded cells, polygonal or rounded, 
 variable in form and size, filled with granular orange proto- 
 plasm, which break up into globose, ciliated zoogonidia. 
 
 Size. Zoogonidia -003 mm. ; cellules •02-'06 mm. diara. 
 
 Parasitic beneath the cuticle of living leaves of dandelion 
 (Taraxacum officinale). 
 
 Professor Trail adds to the above description that "in the autumn 
 thioker-walled resting spores are formed singly in the cells of the food 
 plant." 
 
 Plate LXXXI. Jig. 5. Sorus of Synchitrium Taraxaei X 200. Figs. 6, 
 7, cells with contents converted into zoogonidia, X 400. Fig. 8, free 
 zoogonidia, X 400 ; after Woronin. 
 
 Syuchitzium anemones. Woron. Bat, Zeit. xxvi., p. 100, t 2, 
 f. 8-10. 
 
 Forming dark violet, or almost black, hemispherical warts, 
 the size of a pin's head, which are gregarious, and sometimes 
 confluent. In the centre of each is a sphserical cellule, the wall 
 of which is dark brown and warted. 
 
 Dothidea anemones, DC. Fl. Fr. vi., 143. 
 
 Sphceronenia anemones, Libert. Crypt. Ard., No. 167. 
 
 Septoria anemones, Fuckel Fung. Ehen., No. 518. 
 
 Chytridium ? anemones, D.By. & Wor. Beitr. p. 29. 
 
 Parasitic on the leaves of Anemone nemorosa, 
 
 Plate LXXXII. Jig. 7. Portion of leaf with Synchitrium nat. size. 
 Fig. 8, persistent spore-eell in situ X 200. Fig. 9, persistent spore-cell 
 free X 320 ; after Woronin. 
 
 Synchitrium mexcutialis. Pchl. Fungi Rhen., No. 1067. 
 
 Tubercles confluent on the nerves of the leaves, hemispheri- 
 cal, greenish, depressed above ; umbilicated ; sori oblong, grey, 
 zoogonidia globose, uninucleate, hyaline. 
 
 Size. Sporangia ecbinulate •03-'04 mm. 
 
 Schroet. in Cohn's Beitr. p. 40. Grevillea ii., p. 162. 
 
 Parasitic on leaves oi Mercurialis perennis. April. 
 
 Plate LXXXII. Jig. 1. Section of wart with persistent spore-cell. 
 Fig. 2, persistent cell. Fig. 3, same with contents polygonally divided. 
 Fig. 4, sporangia escaping X 160. Fig. 5, sporangia X 320. Pig, 6, free 
 zoospores X 320 ; after Woronin. 
 
202 CHYTRIDIB2E. 
 
 GSSVS 80. CHIiOROCHYTRIVM. Cohn. 
 
 Plant endophytic ; green, nnicellnlar ; cells globose, or some- 
 what irregularly bi-, tri-, or multi-lobed ; densely filled with 
 chlorophyll, first dividing into large segments, and then these 
 giving origin to innumerable pyriform zoospores, which escape 
 through a tubular process. 
 
 CUorochjrtzium Iiemns. Cohn. Beitr. I., 87. 
 
 The zoospores, impinging on the epidermis of the duckweed 
 at the junction of two cells, after germination commences a tube 
 is produced, which, entering between the walls of the dissepi- 
 ments, proceeds as far as the mesophyllic parenchyma, growing 
 into the intercellular spaces, and forms either a globose, 
 elongated, or irregular-shaped cell. 
 
 Size. Adult cell O-'l mm. diam. 
 
 "Wright in Trans. Roy. Irish Acad. xxvi. (1877), p. 13. 
 Archer in Quart. Journ. Micr. Sci. xv. (1875), p. 104. 
 
 Living in the thallus of Lemna trisulca. Westmeath (Ire- 
 land). 
 
 Cohn says of this species : " Its zoospores attach themselves to the 
 thallus of the duckweed often in hundreds. They force tbeir way 
 through between the epidermal cells, assuming, as the foremost portion 
 gets into the hypodermal tissues, a more or less figure of eight-shaped 
 form : the foremost portion, getting into an intercellular space, dilates ; 
 the portion that has not entered remains unexpanded, and forms a 
 colourless nipple-like projection ; the portion within the thallus expands 
 to many times its original diameter, sometimes dilating and filling up an 
 intercellular space, at others distorting the subadjacent cellular tissue, 
 and frequently itself becoming variously distorted. The cell wall becomes 
 thicker, even laminated ; the chlorophyll contents get dark and dense, 
 and the cell becomes of a dark, nearly opaque green ; sometimes starch 
 granules are seen. The cell contents become segmented, breaking up into 
 a number of pear-shaped zoospores, which escape through the nipple-like 
 projection ; their actual exit was not seen, nor was the number or position 
 of the cilia observed. Of the zoospores, many never succeeded in pene- 
 trating the epidermis of the duckweed upon which they alighted, and 
 such would remain as minute colourless pin's heads on the surface of the 
 Lemna. Some would linger within the mother cell, and might pos,slbly 
 be resting spores." — Abstract by Prof. Perceval W7-ight, loc. cit. 
 
 Plate LXXXI. fig. 9. Chlorochytrium LemniE parasitic on duckweed. 
 Zoospores located in intercellular spaces X 600. Fig. 10, in a more 
 advanced stage x 600. Fig. 11, free zoospores x 600. After Cohn. 
 
OHRoococcAOBa;. - 203 
 
 Class II. PHYCOCHEOMOPHYCE^. 
 
 Plants one or many celled, living in water, or enclosed in a 
 maternal jelly when out of it, mostly in families formed from 
 successive generations of cells. Cell membrane (Cytioderni) 
 not siliceous, combustible. Cell contents (Cytioplasni) a brown, 
 olivaceous, or fuscous endoctrome, destitute of nucleus, and 
 usually without starch granules. 
 
 Propagation by division, and by immovable gonidia, or 
 quiescent spores. 
 
 Order I. G7STIPH0RM. 
 
 Unicellular plants. Cells sphaerical, oblong, or cylindrical 
 enclosed in a tegument, associated in families surrounded by a 
 universal tegument, immersed in a more or less liquid or firm 
 mucilage, variable in colour, for the most part irregularly dis- 
 posed. Division of the cells taking place in one, two, or 
 three directions alternately. Propagation by quiescent gonidia. 
 
 Foecundation unknown. 
 
 Family I. CHROOCOOCACEiE. 
 
 Thallus mucous or gelatinous, amorphous, enclosing cells and 
 families irregularly disposed. 
 
 It may be urged that, as many of the species Included in this family, 
 as well as in the analogous PalmellaceiB, are only conditions of higher 
 forms, they should not have been inserted. In the preparation of a Flora 
 of this kind, however, we are of opinion that whilst the life history of 
 these forms is so imperfectly known, we should not have been justified in 
 excluding them. 
 
 Genus 81. CHROOCOCCUS. MgeU. (1849.) 
 
 Cells globose, or more or less angular from mutual pressure, 
 solitary, or associated in globose cubical or amorphous families, 
 free (not involved in a mother-cell). Cell membrane inmost 
 cases thin, homogenous, achromatic, often confluent in a more 
 or less firm jelly ; cell contents verdigris, or pallid blue green, 
 not rarely yellow or orange. Propagation by division alter- 
 nately in three directions. 
 
204 CYSTIPHOB^. 
 
 Chzoococcus cohaezens. Nag. fide Halh. 
 
 Cells oblong, twin, or in fours, with a distinct hyaline ellipsoid 
 tegument ; cell-membrane thin, achromatic ; cell-contents 
 homogenous, or slightly turbid, blue-green. 
 
 Size. Cells -OOS-'OOe mm. diam. Families of 2-4 indivi- 
 duals. 
 
 Eabh. Alg. Eur. ii., 30. Kirch. Alg. Schles. 261. 
 
 Frotococcus coharens, Kutz. Spec. 197. Tab. Phyc. 1 t. 5. 
 
 Pleurococcus cohcerens, Breb. in Meneg. Nost. Ital. 35, t. iv., 
 I. o* 
 
 On damp walls and flower pots. 
 
 Plate LXXXIII. fig. 1. Cells magnified 400 diam. 
 
 Chzoococcus tnzgidns. Sag. Einz. Alg. p. 46. 
 
 Cells sphserical, oblong-ellipsoid, or more or less angular from 
 compression, single, twin, ternate, or quaternate (rarely 8), 
 associated in families, tegument thick, usually evidently lamel- 
 lose, colourless. Cell-membrane thin ; cell contents bright 
 verdigris green and homogenous, at length becoming brownish 
 and granulated. 
 
 Size. Cells •013--025 mm. diam. Families of 2-4. 
 
 Eabh. Alg. Eur. ii., 32. Kirch. Alg. Schles. p. 262. 
 
 Frotococcus turgidus, Kutz. Tab. i., t. 6, f. 1. 
 
 Hcematococcus binalis, Hass. Alg. p. 331, t. 82, f. 2. 
 
 In swampy places and on moist rocks. 
 
 Not at all UDCommon; often mixed with other algse. Easily dis- 
 tiogaished by its size. 
 
 Plate LXXXIII. fig. 2. Cells magnified 400 diam. 
 
 GENT7S 82. GLOBOCAPSA. Xuti. (1843.) 
 
 Cells sphserical, either single or numbers, associated in 
 families, the single cell included in a vesiculiform tegument, 
 this cell undergoing division into two daughter cells. Each 
 has a distinct tegument, the whole being surrounded by the 
 tegument of the mother cell. This process is repeated' again 
 and again, the original tegument remaining and surrounding 
 the family thus formed. Cell membrane thick, often very thick, 
 equalling or exceeding in diameter the cavity of the cell; 
 colourless or coloured, mostly lamellated, strata not un- 
 frequently separating. Cell contents of various colours, 
 
CHEOOCOOOACB^. 205 
 
 SBruginous, bluisli green, steel-blue, reddish, yellowish, fuscous, 
 &c. Division of the cells in three directions, the last genera- 
 tion of the cells smaller than the early ones. — Babh. Alg. Eur. 
 ii., 34. 
 
 GIseocapsa coracina. Kuta. Phyo. Gen. 174, t. 6, /. 1. 
 
 Thallus crustaceous, very black, lubricous ; single cells 
 spherical, small, tegument very pale violet, distinctly lamel- 
 lose, cell contents homogenous blue-green. 
 
 Size. Cells •0033--004; with envelope ■006--014 mm. 
 Families •009--075 mm. diam. 
 
 Eabh. Alg. Eur. ii., 35. Kirch. Alg. Schles. p. 258. 
 
 Microcystis airovirens, Meneg. Nost. Ital. 76, t. 10, f. 1. 
 
 On rocks, and on boggy ground amongst moss. 
 Plate LXXXUI. fig. 3. Cells magnified 400 diam. 
 
 Gl«ocapsa atzata. {Autz^ Mabh. Alg. Eur. it., 35. 
 
 Thallus crustaceous, mucous, black ; cells ^hserical small, 
 tegument very thick, hyaline, homogenous, two or three times 
 broader than the central cell, cell-contents pale verdigris green, 
 rather granulated. 
 
 Size. Cells •0035--0045 mm., with envelope ■009--014 mm. 
 Families •01--08 mm. 
 
 Nag. Einz. Alg. t. 1, f. 1. Kirch. Alg. Schles. p. 258. 
 
 Microcystis atra, Kutz. in Linn, viii., 375. 
 
 On rocks in mountain regions. 
 Plate LXXXIII. fig. 4. Cells magnified 400 diam. 
 
 Glaeocapsa livida. (Carm.) Kuiz. Tab. I,, t. 21,/. 5. 
 
 Thallus mucous, rounded lobate, broadly expanded hyaline 
 dingy green, or olive brownish, cells very minute, tegument 
 pale bluish, hyaline, cell contents solid dark blue-green. 
 
 Size. Cells •003--006 mm.; with envelope •006--0078 mm. 
 Families •016--05 mm. 
 
 Eabh.Alg. Eur. ii., 36. Kirch. Alg. Schles. 258. 
 
 Palmella livida, Carm. in Grev. Fl. Edin. ; Eng. PL v., 397. 
 Harv. Man. 178. 
 
 Hcematococeus lividus, Hass. Alg. 332, t. 82, f. 5. 
 
 Microcystis livida, Meneg. Nost. 74, t. 9, f. 2. 
 
 On naked ground, or amongst moss and lichens, rarely on 
 rocks, on mountainous moors. 
 
 " Covers the overhanging limestone rooks to a great extent, sometimes 
 as much as several hundred yards together. When fresh it looks like a 
 blackish brown, gelatinous substance, giving the rocks on which it grows 
 
206 CYSTIPHOE^. 
 
 the appearance of being covered with pitch ; on places where it becomes 
 dry by exposure to the sun it is very friable, and on being touched 
 crumbles down to a powder." — Moore, in Sass. loo. cit. 
 
 Plate LXXJLIII.fig. 5. GUBocapsa, livida, drawn from Camuchael's 
 original specimen X 400. 
 
 Glseocapsa caldazioram. Babh. Alg. Eur. 37. 
 
 Thallus irregular thick gelatinous, pale yellowish, cells soli- 
 tary, globose or rather elliptical, tegument sphserical or elliptic, 
 colourless lamellose, lamella often diffuse, the externally one 
 manifestly diffluent; cell-contents homogenous, or rather 
 granulose, pale blue-green. 
 
 Size. Cells -OOS-'OOG mm. with envelope •019--04 mm. 
 
 GlcBocapsa montana var. caldarii, Suringar Obs. 54, t. 4, f. 
 E. Kirch. Alg. Schles. 257. 
 
 On walls, flower-pots, glass, &c., in conservatories and green- 
 houses. 
 
 PMe LXXIII. fig. 6. Cells magnified 400 diam. 
 
 Glsocapsa polydexmatica. Kutz. Tab. 1, t. 20. 
 
 Thallus gelatinous, more or less compact, dirty green, or olive 
 becoming brownish ; cells small sphaerical, tegument very thick, 
 hyaline lamellose, lamellse numerous, concentric, firm ; cell- 
 contents verdigris green, almost homogenous. 
 
 Size. Cells •003--004:5 mm. ; with envelope -023 mm. 
 Families "05 mm. 
 
 Eabh. Alg. Eur. ii., 37. Kirch Alg. Schles. 257. 
 
 Microcystis rupestris, Meneg. Nost. 72, t. 9, f. 1. 
 
 Ecematococcus rupestris, Hass. Alg. 326, t. 82, f. 1. 
 
 On moist rocks. 
 
 " Frond hyaline, gelatinous, yellowish green, easily broken up, about 
 an inch in diameter, shapeless, rough, pellucid, more or less dense in the 
 centre and elevated; when dried collapsed, blackish, cartilaginous, 
 fragile. Subjected to the microscope it appears constituted of hyaline 
 subsphserical vesicles, enclosing yellowish green, spherical or slightly 
 oblong globules usually undivided. Solitary globules, magnified with 
 glasses less powerful are seen free and naked ; by means of a more 
 powerful microscope, almost all are perceived to be clothed with a proper 
 cyst, larger vesicles enclose smaller, and the whole frond appears areo- 
 lated, the hollow areolae containing solitary or binate globules. The 
 vesicles general as well as partial, duplex, triplex, or multiplex, and that 
 without any perceptible order, commonly present concentric circles, 
 generally approximated, evident to the light." — Meneghini. 
 
 Plate LXXXin.fig. 7. Cells magnified 400 diam. 
 
 Glaeocapsa quateznata. Autz. Tai.i., t.20,f. 1. 
 
 Thallus mucous, effused, dirty green, becoming reddish 
 brown ; cells usually spherical, single or twin or quatemate 
 
CHROOOOOOAOEJL. 207 
 
 (rarely 6-8) in families, tegument narrow, lamellose, achromatic, 
 rounded or oblong ; cell-contents rerdigris green, homogenous, 
 or delicately granulated. 
 
 Size. Cells •0032--0045 mm. ; with envelope •007--011 mm. 
 Families •011--022 mm. 
 
 Eabh. Alg. Eur. ii., 37. Kirch. Alg. Schles. 257. 
 
 Coccochloris quaternata, Breb. MS8. 
 
 On rocks or moist ground (Scotland). 
 Plate LXXXIII. fig. 8. Cells magnified 400diam. 
 
 Gleeocapsa axenaxia. {Eass.') Rabh, Alg. Eur. i., 39. 
 
 Thallus mucous, cohaerent, somewhat olive-coloured ; cells 
 large sphserical, tegument thick oblong or almost sphaerical, 
 colourless, lamellose ; lamellse diffluent, cell-contents verdigris 
 green then brownish, distinctly granulated. 
 
 Size. Cells -OOSS-'OOS mm., with envelope •006--014 mm. 
 Families '04 mm. 
 
 Eabh. Alg. Eur. ii., 39. 
 
 Hcematococcus arenanus, Hass. Alg. 830, t. 76, f. 10. 
 
 In springs and thermal waters. 
 Flate LXXXIV. fig. \. Cells "magnified 400 diam. 
 
 Glseocapsa sexuginosa. {Carm.) EuU. Tab. I., t. 21, /. 2. 
 
 Thallus crustaceous, grumous, or cartilaginous, glaucous 
 green ; cells small spheerical, tegument thick colourless, indis- 
 tinctly lamellose, externally not rarely angular, cell-contents 
 verdigris green, homogenous. 
 
 Size. Cells •0022--003 mm. with envelope ■0044--0088 mm. 
 Families -Oie-'OS mm. 
 
 Eabh. Alg Eur. ii., 39. Kirch. Alg. Schles. 258. 
 
 Palmella (sruginosa, Carm. MSS. 
 
 Hcematococcus wruginosus, Hass. Alg. 333, t. 82, f. 3. 
 
 On limestone and other rocks. 
 Plate LXXXIV. fi,g. 2. Cells and families magnified 400 diam. 
 
 Glaeocapsa magma. {Breb.) Kutz. Tab. I., t. 22, f. 1. 
 
 Thallus grumous, rather crustaceous, purple brown, blackish 
 when dry ; cells for the most part sphserical, tegument lamel- 
 lose intense purple or coppery- brown, usually not pellucid, 
 external stratum very broad, globose, paler or colourless, soon 
 diffluent ; cell-contents verdigris green, granulose, often becom- 
 ing brownish. 
 
 Size. Cells •0045--007 mm., with envelope ■006--012 mm, 
 
 2 G 
 
208 CYSTIPHOR^. 
 
 Eabh. Alg. Enr. ii., 42. Kirch. Alg. Schl 259. 
 
 Sorospora montana. Mass. Alg. 309, t. 79, f. 1. 
 
 Palmella montana. Kg. Syst., p. 18. Eng. Fl. v., 396. Eng. 
 Bot. ii., t. 2554. Harv. Man. 179. 
 
 Protococcus magma, Meneg.' Xost. p. 43. 
 
 Viva montana, Lightf. Fl. Scot. 973. Hull. Br. Fl. 314. 
 Eng. Bot. i., t. 2193. Hook Scot, ii., 91. With. An: iv., 
 122. 
 
 Merreitia alpicola, Gray Arr. i., 349. 
 
 " Monntain dulse," of the Scotch. 
 
 On moist rocks. 
 
 " On the mountains of Arran, this lies unattached among loose wet 
 stones, covering them in a straggling manner to a considerable extent. 
 Each frond is 1-1^ inch, in diameter, flattish, somewhat orbicular, 
 between coriaceous and gelatinous, when dry almost horny, of a deep but 
 dull purple colour, much lobed and curled like some (ryrophorte, filled 
 with crowded clusters of granules, which, if minutely examined are found 
 to he mostly arranged in fours " — Hooker. 
 
 In Scotland it is called Mountain Dulse, and, according to Lightfoot, 
 " the Highlanders wash it and rub it between their hands into some 
 water, so as to make a thin pulpy mixture, with which they purge their 
 calves." 
 
 Plate LXXXir. fig. 3. Cells and families magnified 400 diam. 
 
 Glsocapsa rapicola. K'o.tz. Spec. p. ^1. 
 
 Thallus black, then fuscons or brown, crustaceous, thin, rather 
 grnmou.s, cells small, sphaeiical, tegument narrow, not lamellose, 
 fuscous then rusty-brown, for the most part associated in fours, 
 rarely in twos ; outer tegument broad, very pale, globose, enclos- 
 ing numerous smaller families, soon diffluent ; cell-contents pale 
 verdigris green, or rusty brown. 
 
 Size. Cells ■0033--005 mm. Families -07 mm. 
 
 Eabh. Alg. Eur. ii., 43. 
 
 On rocks nmongst moss (Scotland). 
 Plate LXXXIV. fig. 4. Cells and families magnified 400 diam. 
 
 Glaeocapsa sangninea. (Ag.) E7itz. Tal. I., t. 22. 
 
 Thallus effused, gelatinous, thin, blood red or thicker and 
 somewhat; crustaceous, then becoming blackish brown; cells of 
 medium size, sphsrical, tegument intense blood red, not lamel- 
 lose, in the middle pale red, the extreme outer colourless or 
 nearly so, very broad, globose or angular ; cell-contents pale ver- 
 digris green, gvaiiulose. 
 
 Size. Cells with envelope ■0037-'009 mm. Families to 
 •14 mm. 
 
CIlEOOCOCCACEiE. 209 
 
 Eabb. Alg. Ear. ii., 43. Kirch. Alg. Schles 259. 
 Palmella sanguinea, Ag. Syst. p. 15. 
 
 Hmmatococcus sanguineus. Ag. Icon. t. 24. Harv. Man. p. 
 181. Hass. Alg. 329, t. 79, f. 2. Eng. Fl. t., p. 395. 
 
 On rocks. 
 
 Plate LXXXF. fig. 1. Cells and families magnified 400 diam. 
 
 Glseocapsa Ralfsiana. (JSarv.) Eutz. Tat. l., t. 23. 
 
 Thallus gelatinous, compact, dark purple brown ; cells of 
 medium size, sphserical, tegument very thick, opaque, and in- 
 tense purple, the outer very broad, usually angular from mutual 
 compression, almost colourless, rarely diffluent, enclosing 
 smaller families of 2, 4, 6, 8 ; cell-contents granulated, pale ver- 
 digris green. 
 
 Size. Cells with envelope •01--017 mm. Small families 
 •022-'04 mm. Large families, to "17 mm. 
 
 Kabh. Alg. Eur. ii., 44. 
 
 Sorospora Ralfsii, Hass. Alg. 310, t. 79, f. 3. 
 
 Palmella Ralfsii, Harv. Man. 179. 
 
 Amongst moss and lichens. 
 
 " Thallus a few lines in diameter, gelatinous, somewhat areolate, or as 
 if composed of numerous small vesicles massed together, each of which 
 contains 2-4 or 8 large blood red granules, which are much larger and of 
 a far deeper colour than those of Cr. magma." — Harvey. 
 
 Plate LXXXF. Jig. 2. Cells and families magnified 400 diam. 
 Glseocapsa Shuttlewoithiana. KuH. Tab. I., t. 2S,f. 1. 
 
 Thallus gelatinous, rather hard, compact, dark rufous brown ; 
 cells small sphaerical, tegument very thick, many times broader 
 than the central cell, globose, intense orange red, the outer glo- 
 bose or angular, homogenous, pale orange, or (rarely) colour- 
 less, all, except the inner, soon diffluent ; cell-contents pale 
 verdigris green. 
 
 Size. Cells with envelope •0075-013 mm. Families -035 
 mm. 
 
 Eabh. Alg. Eur. ii., 44, Kirch. Alg. Schles. 259. 
 
 On moist rocks, and amongst moss. 
 Plate LXXXK fig. 3. Cells and families magnified 400 diam. 
 
 GIseocapsa lupestzis. Kviss. Tab. PJtyo. I., t. 22, f. 11 
 
 Thallus dark brown, crustaceous, rather hard ; cells rather 
 large, spheerical ; tegument very thick, lamelluse, yellow or 
 
210 CYSTIPHOR^. 
 
 golden brown, the outer permanent, yellowish or becoming pale ; 
 cell-contents verdigris green, granulose. 
 
 Size. Cells •006--009 mm. with envelope. Families 
 •015--075 mm. 
 
 Eabh. Alg. Eur. ii., 47. Kirch. Alg. Sehles. p. 260, 
 
 On rocks. 
 Hate LXXXIF. fig. 5. Cells and families magnified 400 diam. 
 
 Genus 83. APH&NOCAPSA, Nag. (1849.) 
 
 Cells spherical, with a thick, soft, colourless tegument, con- 
 fluent in a homogenous mucous stratum. Cell division as in 
 Gleoeocapsa. — Rdbh. Alg. Eur. ii., 48. 
 
 Aphanocapsa vizescens. {Sass.') Salli. Alg. Eur. n., 248. 
 
 Thallus gelatinous, more or less expanded, dirty green, or 
 olive, becoming brownish, cells of medium size, pale bluish- 
 green, solitary or in pairs, tegument scarcely visible. Cell 
 contents homogenous, sometimes with a central vacuole. 
 
 Size. Cells about -0055 mm. diam. 
 
 Sorosporium virescens, Hass. Alg. 310, t. 78, f. 8 a. 
 
 Aphanocapsa parietina, Nag. Einz. Alg. t. Ii, f. 1, 
 
 On stones, rocks, &c. 
 
 Flate ZXXXVI. fig. 1. Cells magnified 400 diam. 
 
 Aphanocapsa zivulaiis. {flarm^ Babh. Alg. Bur. rt., 49. 
 
 Thallus hemispherical, gelatinous, tuberculose, often confluent, 
 sernginous-green, becoming brownish when dry ; cells spherical, 
 scattered, single or in pairs, tegument very thick, not lamellose, 
 colourless, soon diffluent. Cell-contents bluish-green, deUcately 
 granular. 
 
 Size. Cells about 'OOo-'OOB mm. diam. 
 
 Palmella rivularis, Carm. MSS. Harv. in Hook. Eng. Fl. 
 v., p. 397. Harv. Man. 177. 
 
 Coccochloris rivularis, Hass. Alg. 317, t. 78, f. 6 o, 6. 
 
 On rocks and stones inundated, in mountain streams. 
 
 " Fronds one-fourth or half an inch in diamecer, hemispherical, tnber- 
 cnlar, firmly adhering, sometimes cohering into a broad cmst. Colour 
 vivid green." — Carmichael. 
 
 Plate LXXXFI.fig. 2. Cells of A. rivularis, X -400. 
 
 Aphanocapsa Gzevillei. {Hass.) Babh. Alg. Eur. n., 50. 
 
 Thallus gelatinous, globose, densely aggregated, more or less 
 confluent, dirty gieeu, from olive to brownish when dry ; cells 
 
CHHOOCOCCACE^. 211 
 
 sphasrical or elliptic, rather crowded, single or in pairs, nestling 
 in a homogenous jelly, tegument quickly diffluent, cell-contents 
 blue-green, delicately granulose. 
 
 Size. Cells -OOSS-'OOe mm. diam. 
 
 Kirch. Alg. ScMes. 261. 
 
 Coecochloris Grevillei, Hass. Alg. 318, t. 78, f. 7 a, b, 8. 
 
 Palmella botryoides, Grev. Crypt. PI. t. 243, f. 2. Eng. 
 Fl. v., 396. Eng. Bot. ii., p. 207. Grev. Fl. Ed. 323. Mack. 
 Hib. 244. 
 
 Palmella Grevillei, Berkl. Glean, p. 16, t. t., f. 1. Harv. 
 Man. 177. 
 
 Botrydina Grevillei, Meneg. Nost. p. 47. 
 
 Byssus botryoides, Huds. Ang. 608. Lightf. Fl. Scot. p. 
 1006. Rehl. Cant. 447. 
 
 Cocochloris radicata, Johnst. Fl. Berw. ii., 262. 
 
 Olivia botryoides, Gray Arr. i., 349. 
 
 Byssus pulverulenta viridis, Dillen. Muse. 3, t. 1, f. 5. 
 
 Byssus botryoides saturate virens, Ray. Syn. 56, No. 5. 
 
 On damp heaths and moors. 
 Plate LXXXFl.fig, 3. a, natural size j b, cells magnified 400 diam. 
 
 Aphanocapsa depzessa. (Hass.) Baih. Alg. Eur, ii., 51. 
 
 Thallus somewhat hemispherical, depressed, gelatinous, green. 
 Cells sphaerical or irregular, variable in size. 
 
 Size. Cells •0025--003 mm. 
 
 Palmella depressa, Berk. Glean. 19, t. 5, f. 4. Harv. Man. 
 178. 
 
 Coecochloris depressa, Meneg. Nost. 68. Hass. Alg. p. 316, 
 t. 78, f. 4 a, b. 
 
 Growing on an old pump, at Cotterstock, Northamptonshire, 
 constantly moistened with the drippings from the spout. 
 
 " Fronds bright yellow-green, gelatinous, subhemispherioal, depressed, 
 crowded together, filled with more or less globose or angular very minute 
 granules." — JBerheley. 
 
 Plate LXXXfl. fig, 4. a, plant natural size ; 6, cells magnified 400. 
 
 Genus 84. MICROCYSTIS, ^'itiz. (1833.) 
 
 Cells spherical, numerous, densely aggregated, enclosed in a 
 very thin globose mother vesicle, forming solid families, singly, 
 or several, surrounded by a universal tegument. Cell division 
 in three directions alternately. 
 
 This genus as defined by Eabenhorst {Alg. Em: II., 51) not appearing 
 to differ essentially from AnacysUs, both are united in this work. 
 
212 CYSTIPHOR^. 
 
 BSiczocystis protogenita. (Stos.) Babh. Alg. Eur. ii., 51. 
 
 Thallus membranaceous, thin, green; families small, angular 
 from mutual pressure ; cells small, sphserical ; cell-contents 
 granular, pale blue-green. 
 
 Size. Families, -02 mm. Cells, •0015-002 mm. 
 
 Micraloa protogenita. Bias. Alg. Micr, t. xix. Meneg. Nost. 
 t. xiv., fig. 1 (partly). 
 
 In water long standing, stagnant ditches, amongst other 
 Algee, &c. 
 Flate LXXXVI. fig. 5. Famflies magnified 400 diam. 
 
 Microcystis mazginata. {Meneg.) Kirch. Alg. Schl. 255. 
 
 Thallus sphserical, flattened, or orbicular and lens-shaped, 
 sometimes confluent, pale-green, colourless at the margin ; cells 
 minute ; cell contents blae-green, at length granular. 
 
 Size. Cells -OOS-'OO^ mm. Families -S-'OS mm. 
 
 Anacystismarginata, Meneg. Nost. 93, t, 13, f. 1, Babh. Alg. 
 Eur. ii., 52. 
 
 In ditches, free swimming. 
 
 Plate LXXXVI, fig. 6. Families magnified 400 diam. 
 
 Gekcs85. CLATHROCYSTIS. Henfrey. (1856.) 
 
 Frond, a microscopic gelatinous body, at first soKd, then 
 saccate, ultimately clathrate (fragments of the broken fronds 
 occurring in irregularly lobed forms) composed of a colourless 
 matrix, in which are imbedded innumerable m.inute cells, which 
 multiply by division within the frond as it increases in size. — 
 Quart. Joum. Micr. Sei,, 1856, p. 53. 
 
 Clathzocystis aznginosa. Senf. Micr. Jov/m. 1856, p. 53, t. 4, , 
 /. 28-36. 
 
 Fronds floating in vast strata on freshwater pools, forming a 
 bright green scum, presenting to the naked eye a finely granular 
 appearance ; when dried, appearing like a crust of verdigris ; 
 cells minute. 
 
 Size. Fronds ■03--13 mm. ; cells •0025--0035 mm. 
 
 Eabh. Alg. Eur. ii., 54. Kirch. Alg. Schles. 254. 
 
 Microcystis (Bi-uginosa, Kutz. Tab. i., t. 8. 
 
 Polycystis wrtigiTwsa, Kutz. Spec. 210. 
 
 On fresh water lakes. 
 
 "The smallest fronds met with are usually roundish or ellipsoidal. 
 When quite young they appear to be solid, but as they grow by the multi- 
 plication of the internal cells and the secretion of gelatinous matter, the 
 expansion takes place chiefly near the periphery, so that the frond becomes 
 a hollow body. The walls of the sac then give way, and, as the expan- 
 
CHROOCOCCAOB^. 213 
 
 sion proceeds, orifices are formed in different parts, until the whole 
 becomes a coarsely latticed sac or clumsy net of irregularly lohed form. 
 Then this becomes broken up into irregnlar fragments of all shapes and 
 sizes (giving the stratum a granular appearance to the naked eye), each 
 of which recommences the expanding growth, and becomes a latticed 
 fnind. The internal cells are very minute, but have a distinct margin 
 with internal granules. They multiply by dividing into two and four. 
 The gelatinous frond always presents a transparent border or peripheral 
 stratum, destitute of green cells ; but no boundary membrane exists, the 
 surface exhibiting a softened or half-dissolved aspect. On the approach of 
 winter the fronds ceased to increase, and by degrees most of the gelati- 
 nous masses faded to a light brownish tint, swelled up and settled to the 
 bottom of the water in light flooculent clouds. They appear to become 
 half-dissolved, and to allow the green cells to become free, as many of the 
 latter were found free, adhering to the sides of the vessel. Perhaps these 
 '•eproduce the fronds in the next season. No zoospores were ever de- 
 tected." — Henfrey. 
 
 ClathrocysUs roseo-persicina, Cohn., is already included in this work, as 
 Pleurococcus roseo-fersicinus, pi. 2, fig. 6. 
 
 Plate LXXXVI. fig. 7. a, Thalli magnified 200 diam. ; b, cells mag- 
 nified 400 diam. 
 
 Genus 86. CCELOSPH.a:RIUAI. Nag. (18+9.) 
 
 Thallus globose, small, vesicular, hollow, composed of small 
 cells, which are associated in families at the periphery, im- 
 mersed in a mucous stratum, formed from the speedily confluent 
 teguments. Increase by division of the cells in all directions. 
 
 Coelospheexium Kutzingianum. Nag. Eini. Alg. p. 54, t. 1 c. 
 
 Families sphserical. Cells subglobose, geminate, or quater- 
 nate, loosely disposed ; cell-contents blue-green, delicately 
 granulose. 
 
 Size. Cells ■002--005 mm. ; families -06 mm. and more. 
 
 Rabh. Alg. Eur. ii., 55. Quart. Journ. Micr. Sci; 1869, p. 
 197. Kirch. Alg. Schles. 254. 
 
 In ponds, meres, &c. 
 
 Plate hXXXVII. fig. 1. Families magnified 400 diam. 
 
 Gjsnus 87. GOMPHOSPHiERIA. Kuta. (1836.) 
 Cells wedge-shaped, peripherical, 2-4-8 associated in radiating 
 families nestling in jelly, covered with a tegument, and forming 
 a solid globose free-swimming thallus. Cells dividing alter- 
 nately in three directions. 
 
 Gomphosphsexia aponina. Kuta, Tab. i., t, 31,/. 8, 
 
 Thallus microscopical, blue-green, often becoming pale, tegu- 
 ment colourless, rather thick and somewhat lamellose, central 
 cells smaller, cell-contents verdigiis or pale blue-green. 
 
214 CYSTIPHOE^. 
 
 Size, Cells '004: mm. diam. to -Ol mm. long ; families "05 mm. 
 Eabh. Alg; Eur. ii., 56. Kirch. Alg. Sohles. 255. 
 
 In ditches. 
 
 Plate LXXXVII. fig. 2. Families magnified 400 diam. ; a,l>, c, d, 
 cells in various stages of subdivision, further magnified — after Beinsch. 
 
 Gekus 88. UBRISIHOPEDIA. Meyen. (1839.) 
 
 Cells globose, at the time of division oblong, rather thick, 
 teguments confluent, 4-8-16-32-64-128 associated in tabular 
 families of a single stratum, forming a quadrate, plane, free- 
 swimming thallus. 
 
 Goebel has observed the formation of zoospores in this genus. See 
 " Botanisohe Zeitung," 1880, p. 490. 
 
 Blezismopedia violacea. Kute. Spec. 472. 
 
 Thallus mucous, colourless, or nearly so, indefinite, families 
 small, composed of 4-32 remote very minute cells ; cell-contents 
 homogenous, violet. 
 
 Size. Cells •001--0015 mm.; families -015 mm. 
 
 Rabh. Alg. Eur. ii., 57. Kirch. Alg. Schles. 254. 
 
 In ponds, ditches, &c., amongst other Algas. " 
 Plate LXXXVII. fig. 3. Families magnified 400 diam. 
 
 Meiismopedia glauca. Nag. Eins. Alg. t. 1, D. 1. 
 
 Thallus more or less limited, glaucous green, margin slightly 
 sinuately crenate ; families composed of 16-48-6-1 (rarely more) 
 oval or globose cells ; cell-contents pale blue-green. 
 
 Size. Cells -OOS-'OOS mm. ; families •04--05 mm. 
 
 Rabh. Alg. Eur. ii., 56. Kirch. Alg. Schles. 253. 
 
 Oonium glaucum, Ehrb. Infus. 56, t. 3, f. 5. 
 
 In stagnant water. 
 PMe LXXXVII. Jig. 4. Families magnified 400 diam. 
 
 Meiismopedia punctata. Meyen in Wirgm. Arch. 1839, p. 67. 
 
 Thallus less limited, almost colourless, for the most part com- 
 posed of 4-64 remote cells ; cell-contents pale blue-green. 
 
 Size. Cells '033 mm. ; families '06 mm. 
 
 Kutz. Tab. i., t. 38, f. 3. Rabh. Alg. Eur. ii., 57. Kirch. 
 Alg. Schles. 254. 
 
 In stagnant water. 
 
 Plate LXXXVII. Jig. 5. Families magnified 400 diam. 
 
CHROOCOCCACE^. 215 
 
 Meiismopedia ventziculi. Bobin Veg. Par, t. 1,/. 8. 
 
 Thallus miicons-membranaceous, firm, ■whitis'h or yellowish ; 
 families composed of numerous cells (8-4096) ; cell-contents 
 pale bluish. 
 
 Size. Cells '008 mm. diam. ; families -OS-'OS X ■016--02 mm. 
 
 Rabh. Alg. Eur. ii., 58. Kuchenm. Par. p. 13, t. 1. 
 
 Merismopcsdia Goodsiri, Husem. de Anim. p. 13. 
 
 Sarcina ventriculi, Goodsir in Edin. Med. and Surg. Journ. 
 1842, p. 430, t. 57. Welcker in Quart. Journ. Micr. Sci. viii., 
 p. 163. 
 
 Ill the human stomach, &c. 
 
 Doubtfully included here. Recently authors have classed it with 
 Schizomycetes in preference to Algee. 
 
 Plate LXXXVII. fig. 6. a, cells magnified 400 , 6, cells very 
 highly ntiagnified. After Eohin. 
 
 MCerismopedia reuis. {Repw.) Rabh. Alg. Bur. Ii., 59. 
 
 Families composed -of from 8 to 64 cells. 
 Size. No dimensions given, 
 
 Sarcina renis, Hepworth in Micr. Journ. v. 1857, p. 1, 
 with woodcut. 
 
 In the human kidneys. 
 
 This very obscure - organism, like the last, is included here with con- 
 siderable doubt. It may be said that nothing more is known of it than 
 the meagre diagnosis above given. Sarcina ossium, Stephens, Ann. Nat. 
 Hist. ser. 2, vol. xx., p. 514, is equally uncertain. 
 
 Plate LXXXVII. Jig. 7. Cells very considerably but indefinitely mag- 
 nified. After Hepworth. 
 
 Genus 89. TETRAFEDIA. Reinsdi. (1867.) 
 
 Cells compressed, quadrangular or triangular, equilateral, 
 becoming subdivided into quadrate or cuneate segments, or 
 rounded lobes, either by deep vertical or oblique incisions, or 
 by wide angular or rounded sinuses. 
 
 " Amongst unicellular Algse falling under the class CMorophyllacece, 
 forms with specially figured cells — that is, otherwise than globular, ellip- 
 soidal, or cylindrical, with more or less abruptly or broadly rounded ends 
 —are, as is well known, numerous ; but amongst such plants belonging 
 to the class PhycoohromaceiB , so frequently found in the same situations 
 associated with the foregoing, so far as I am aware, not until recently has 
 attention been drawn to any examples of a specially figured outline. 
 
 " It does not appear, until the genus Tetrapedia was founded by Professor 
 Keinsoh for two new and singular exceedingly minute chroococcaceous 
 forms, that examples of specially figured forms were known in this family 
 of Algae. 
 
 2 H 
 
216 CYSTIPHOK^. 
 
 " So far as our acquaintance with these little Algsa reaches, there appear 
 to exist four (if not five) distinct, yet kindred forms of figured, ' Chroo- 
 coccacese ' — their remarkable shapes preclude their being regarded as 
 ' Lichen-gonidia,' but whether mature plants or stages in the growth of 
 any more complicated structure remains a problem. Ours are at least 
 forms which here and there recur, and one can at once recognise them as 
 always offering the same charactersitics and as maintaining their apparent 
 individuality. Whether they are ' species ' or^ not, it may be a matter 
 of convenience, should observers meet them elsewhere, and be able to 
 throw a light upon them, to have at least a means of their recognition ; 
 for these reasons it occurs to me as desirable to record them under 
 Reinsch's genus." — W. Arch&r in GreviUea i., p. 44. 
 
 Tetrapedia Crax-Michaeli. Beinsch Alg. Mitt. Sraiik. 
 
 Cells quadrate, lateral margins entire, with two shallow con- 
 cavities, each extending half the length of the side, thus pro- 
 ducing an obtuse-angled central prominence, deeply incised at 
 the angles, incisions diagonal, rectilineal, deep, acute below, 
 slightly expanding upwards, thus bisecting the angles, and 
 dividing the cell into four broadly cuneate segments, the upper 
 angles of which are subacute (the incisions ultimately com- 
 pleted, and the cell breaking up ?) ; in side view lanceolate, 
 ends acute. 
 
 Size. Cells •008--012 mm. diam. 
 
 Archer in Grevillea i., p. 45. Keinsch Algenflora, t. i., fig. 6. 
 
 In running water (very scantily) near MuUingar,. Co. West- 
 meath, Ireland. 
 
 Plate LXXXriI. jig. 8. Cells magnified 600 diam. 
 
 Tetrapedia Reinschiana. Archer in Gremllea I., p. 46, i. 3, /. 
 
 11-13. 
 
 Cells quadrangular, two opposite margins excavated by a 
 wide triangular sinus, thus subdividing the cell into two broadly 
 cuneate segments connected by a wide isthmus, and somewhat 
 convex on their lower margins ; the other two opposite margins 
 of the cell, that is the upper margins of the segments, very 
 slightly concave at the middle, somewhat raised towards the 
 acute outer angles ; in side view oblong, constricted at the 
 middle, ends rounded. 
 
 Size. Largest cell •0075-"01 mm. diam. 
 
 In moor pools, Co. Dublin and Wicklow. 
 Plaie LXXXFII. fig. 9. Cells magnified 600 diam. 
 
 Tetrapedia setigera. Archer in Grevillea I., p. 46, i. 3, fig. 14-17. 
 
 Cells triangular, the lateral margins somewhat deeply ex- 
 cavated by a broad rounded sinus dividing the cell into three 
 
CHROOCOCOACEJi;. 217 
 
 lobes, rounded at the ends, and each terminated by a vory 
 delicate straight bristle, in length about equal to the diameter 
 of the cell ; in side view oblong, somewhat inflated at the 
 middle at each side, ends round, and each seen tipped by the 
 bristle. 
 
 Size. Cells without bristles •0062-*0075 mm., including the 
 bristles ■016--02 mm., from end to end. 
 
 In moor pools, Co. Dublin and Wicklov*^. 
 
 PUte LXXXVII. fig. 10. Cells magnified about 600 diam. After 
 Archer. 
 
 Genus 90. SYNECHOCOCCVS. Nag. (1849.) 
 
 Cells oblong, usually single, sometimes 2-4 connected in a 
 series constituting a family. Cell membrane thin, cell-contents 
 blue green ; now and then yellow or pale orange. Tegument 
 absent. Division in one direction only. 
 
 Synechococcus crassus. Ai'cher Micr.Jauvn. 1867, p. &T. 
 
 Cells broadly elliptic, about one half longer than broad ; cell 
 wall Tery thin. 
 
 In shallow pools. Bray's Head, Ireland. 
 
 Larger than the largest of Nageli's species (S. cerugtnosus), from ■which 
 it is also distinguished by its elliptic or egg-shaped cells, somewhat 
 narrowing towards the gradually rounded ends, and not cylindrical, with 
 rounded truncate ends. 
 
 No figures or measurements of this species hare been published, and 
 only the bare description reproduced above. 
 
 Genus 91. GI.(EOTHECE. Mff. (1849.) 
 
 Cells cylindrical-oblong, rounded at the ends ; division trans- 
 versal in one direction. Other characters as in Glceocapsa. 
 Tegument very thick, lamellose. 
 
 Gloeothece cystifeza. (ffoss.) Eahh. Alg. Eut'. II., 61. 
 
 Cells oblong-cylindrical, 2-4 associated in families ; involved 
 in a special universal tegument which is globose or oval, l|-3 
 times as long as bread. Cell-contents verdigris green. 
 
218 CYSTIPHOR^. 
 
 Size. Cells -004-005 mm., with tegument •008--012 mm. 
 Families -O^S-'OiS mm. 
 Kirch. Alg. Schles., 251. 
 Coccochloris ci/stifera, Hass. Alg. 441, t. 103. 
 GlcEothece devia, Xag. Eiiiz. Alg., t. 1, f. G. 3. 
 
 On rocks. 
 
 Plate LXXXrill. fig. 1. Cell? and families magnified 400 diam. 
 
 Gloeothece granosa. Stbh. Alg. Eur. u., 61. 
 
 Thallus compact-gelatinous, somewhat cartilaginons, granu- 
 lose, blue-green; cells oblong, twice as long as broad, usually 
 2-4 associated in families ; tegument very broad, jnany tinie.s 
 exceeding the central cell, distinctly lamellose, colourless or 
 nearly so, lamellse scarcely diffluent ; cell contents homogenous 
 or granose, pallid blue-green. 
 
 Size. Colls •014--018 mm. diam. 
 
 Palmella granosa. Berk. Glean, ii., p. 19, t. 5, t. 5. 
 
 JSLicrocystts granulosa, Mfneg. Nost. 85. 
 
 Hcematococcus granosus, Hass. Alg. 327, t. 81, f. 6. Jeuner 
 Tnnb. Wells, 90. Harv. Man. 181. 
 
 On mosses in swamps. 
 Plate LXXXVIIl. fig. 2. Cells and families magnified 400 diam. 
 
 Genus 92. AFHANOTHECE. Nag. (1840.) 
 
 Differing from Glceothece in all the teguments being usually 
 confluent. Cells oblong or subcylindrical. Cell-contents now 
 and then green, and then with difficulty distinguished from 
 Palmella. 
 
 Aphanothece pzasina. Br. in Bdbh. Alg. No. 1572. 
 
 Thallus gelatinous, more or less globose, tuberculose, the 
 size of a cheiTy, intense bright leek-green, sometimes confluent, 
 and then lobed, internally now and then interwoven with hyaline 
 threads ; cells oblong or ovoid, 1-2 times longer than broad, 
 after division sphserieal, tegument none, cell-contents verdigris 
 green. 
 
 Size. Cells •005--006 x ■008--011 mm. 
 
 Eabh. Alg. Eur. ii., 65. Kirch Alg. Schlos. 252. 
 
 CoccocMoiis stagnina. West and Wall. Herb. Belg. 1099. 
 
 Aphanothece Mooreana, Lager. Sver. Algflora p. 44. 
 
 Palmella Mooreana, of this work p. 12, t. 5, f. 4. 
 
 In ditches and stagnant ponds. 
 
chroooocoaobjE. 219 
 
 We are of opinion that this and the next species, as well as the 
 Talmella Mooreana figuied on the 5th plate of this woii%, are all one 
 species. 
 
 Plate LXXXVIll. fig- 3. a, natural size ; b, cells magnified 400 
 diam, 
 
 Aphanothece stagnina. (^Spr.) Rabh. Jig. Eur. Ii., 66. 
 
 Thallns gelatinous, oblong or elliptical, or nearly globose, 
 from the size of a pea to that of a cherry, pale hyaline verdi- 
 gris green ; cells oblong-oval, always smaller than in A.prasina, 
 ■^-1 times longer than broad, tegument none, cell-conteuts pallid 
 verdigris green. 
 
 Size. Cells •003--005 x -OOS-'OOS mm. 
 
 Kirch. Alg. Schles. 252. 
 
 Coecochloiis stagnina. Spreng, Linn. Syst. iv,, p. 372. 
 
 In stagnant water. 
 
 It is very doubtful whether any definite specific character can be found 
 to separate this fiom A. prasina. As we have taken hoth from the 
 same pond, the difference in colour, and in the size of the cells, may be 
 assumed to he attributable only to difference in age. 
 
 Plate LXXXVIll. fig. 4. u, natural size ; J, cells magnified 400 
 diam. 
 
 Genus 93. HOKALOCOCCVS. Kutz. (1863.) 
 
 Thallus globose, gelatinous ; internal cells irregularly united 
 in a plane, oblong body, immersed in the gelatinous thallus. 
 
 Homalococcus Hassallii. Ktttx. Osterprog. 1863, p. 6. 
 
 Thallus globose, soft, green, of the size of a pea or a hazel- 
 nut ; cells rounded or somewhat angular. 
 Size. Cells about -006 --007 mm. diam. 
 Eabh. Alg. Eur. ii., 69. 
 Coccochloris hyalina, Hass. Alg. 315, t. 78, f. 2, a, I. 
 
 In stagnant water. 
 
 Plate LXXXVIll. fig. 5. u, natural size; b, cells magnified 400 
 diam. After Hassall. 
 
220 Nematogen^. 
 
 Order II. KEMATOGEN^. 
 
 Plants multicellular, or pseudo-multicellular. Cells forming 
 a filament {Trichome), usually included in a tubular homogenous 
 or lamellate sheath {vagina). Filaments {Trichomes) either 
 simple or branched. — Rabh. Alg. Eur. ii., 70. 
 
 Thnret nnites Cystiphorcs and Nematogence in one order under the 
 name of CryptophycetB, representing the OyUiphorte by a Tribe called 
 Chroococcacece and Nematogence by another Tribe termed Nostoehinete, so 
 that really the difference is only one of name. 
 
 TsiBE 1. nostochinea:. 
 
 Trichomes simple or branched, with an obtuse, or acute and 
 setiform apex, either naked or enclosed in a sheath. Repro- 
 duction by fragments of the trichome {hormogonia) which are 
 endowed with motion after separating from the mother plant 
 =IIormogonece. Thuret. 
 
 The Nostoehinete, as interpreted by Messrs. Bomet and Thnret, are 
 subdivided into two gronps, or snb-tribea. 
 
 Snb-Tribe 1. PsiLONKMiE with the filaments not attenuated at one ex- 
 tremity to a hair-like thread. 
 
 Snb-Tribe 2. Teichgphoee^ with the apex of the filament attenuated 
 to a hair-like extremity. 
 
 Whilst the Chroococcaceas reproduce themselves by means of isolated 
 cells, the Nostochineae reproduce themselves by the fragments of fila- 
 ments (called hormogones), which are endowed with mobility after 
 separating themselves from the mother plant. 
 
 The filaments of IfostocMnete are composed essentially of colonred 
 cells disposed in a row. This assemblage of cells islspecially designated 
 a trichome. The trichome is either naked, or immersed in mucilage, or 
 enclosed in a sheath. 
 
 The presence or absence of heterocysts, their number, their situation 
 in the filament, are characters important to note, but which hitherto 
 have been much neglected. Easily recognized in the living plant by 
 their yellow colour from the other cells of the trichome, but sometimes 
 difficult to distinguish in dried specimens. In doubtful cases it is to be 
 remembered that the heterocysts are united always with the sheath, and 
 if that envelope is defective in the other cells it will suffice to apply an 
 appropriate re-agent, such as potass, solution of iodine, &o., to obtain 
 evidence of their nature. 
 
 Sometimes the terminal cells of the trichome resemble the others (as 
 in Lyngiya and Scytonema), sometimes the filaments are terminated by a 
 hyaline hair, elongated and deprived of its coloured contents, with a 
 diameter much less than the ordinary joints of the trichome (as Calo- 
 thrvn, Sivularia, &c.). This distinction, which corresponds in another 
 Instance to the principal growing point of extension of the filaments, is 
 very marked in the living state, and especially in individuals in full 
 vegetation. When, on the contrary, the plants are old, and the summit 
 broken and their hormogones dispersed, the complete filaments are 
 sometimes very rare, and must be sought with some perseverance. 
 
KOSTOCB^. 
 
 221 
 
 Certain genera of NostocMneae have the filaments constantly simple 
 (^Nostoc, Anabaena), others have the filaments frequently provided with 
 lateral branches (Scytonemece, OalotrichecB). Sometimes these rami- 
 fications are normal, and result from the regular division of the 
 trichome {Eimilaria, &c.), sometimes accidental and irregular. These 
 produce themselves v? hen the trichome has broken, they grow and issue 
 laterally from the sheath, when it is not rare to observe the base of the 
 filaments of certain lAjnghya, or, again, when the hormogones are not able 
 to escape freely, they germinate in the interior of the sheath. Indeed, 
 it is very frequent that the germinations develope themselves in fila- 
 ments of all ages, but in that case the young filaments are not at all 
 enveloped by the general sheath of the filament that bears them. 
 
 Nostocs should be dried as quickly as possible after they are collected, 
 otherwise the triohomes escape and the sheaths are left empty. — Thwet, 
 in Ann. des Soi. Nat. 6 ser., Vol. i.,pp. 372-382 (1875). 
 
 The following is a dichotomous key to the classification as proposed by 
 M. Thuret:— 
 
 ("Filaments tapering at the top into a hyaline 
 
 1 J. hair 12 
 
 ( Filaments always destitute of an apical hair .... 2 
 
 rFilaments in which some of the cells change 
 
 2 <. into heterocysts ........ .3 
 
 (.Filaments without heterocysts 7 
 
 (■Filaments with lateral ramifications 10 
 
 \ Filaments without ramifications ...... 4 
 
 /Filaments immersed in a gela- 
 \ tinous mucilage of a determi- 
 
 4 NosTOCEjE < nate shape Nostoc. 
 
 y Filaments free or immersed in an 
 
 V. amorphous diffluent mucilage .... 5 
 
 (Filaments consisting of a coloured trichome 
 enclosed in a hyaline sheath 6 
 Filaments without a sheath distinct from the 
 trichome A. B. C. 
 
 1. Heterocysts scattered in the irichome. 
 
 A. Spores originating in cells not adjoin- 
 
 ing the heterocysts Anaiaena. 
 
 /3 Triohomes united in small fioat- 
 
 ing bundles .... Aphanitomenon. 
 
 B. Spores originating in cells placed on 
 
 each side of the heterocysts . . . SpJtwrozyga. 
 
 2. Heterocysts terminal (at both ends of the triclwme). 
 
 C. Spores originating in cells placed just 
 
 below the heterocysts . . . Oglmdros;perMum. 
 
 r Cells disc-like. Spores very prominent. He- 
 6 < terooysts placed at regular intervals . . . Nodularia. 
 ICells longer than broad. Spores none . . . Microohate. 
 
 ( Filaments spirally twisted . . . SpiruUna. 
 
 I i-i;N<3ByB.E I filaments not spirally twisted .... 8 
 
222 
 
 sematogen'js. 
 
 ^Filaments without a sheath distinct from 
 the triohome 
 
 /3 Filaments agglutinated in small float- 
 ing bundles ..... 
 Filaments formed of one or several coloured 
 trichomes enclosed in a transparent sheath, 
 from which the trichomes emerge to repro- 
 duce new filaments ..... 
 
 B. 
 
 ' Sheath containing several trichomes, at least 
 in the larger filaments .... 
 
 A. Filaments growing in scattered 
 
 creeping, erect, or floating wick- 
 like bundles .... 
 
 B. Filaments bundled, erect, growing 
 
 in small rounded tufts, or in felt- 
 like tnrf of indefinite extent. 
 Trichomes very slender 
 
 Sheath enclosing only a single triohome 
 
 A. Filaments simple, or only excep- 
 tionally exhibiting the beginning 
 of ramification where the tri- 
 ohome issues from the side of 
 
 the sheath 
 
 13 Filaments agglutinated in 
 wick-like bundles . 
 Filaments branched. Ramifications 
 produced by the branching of the 
 triohome outside the sheath, very 
 irregular, and often geminate, as 
 in Scytonema .... 
 
 Trichomes of which the cells 
 only multiply in the direotiou 
 of the length of the filament 
 
 Trichomes of which the cells 
 multiply as well in the direc- 
 tion of the breadth of the 
 filament, at least where the 
 branches, which are always 
 produced by lateral multipli- 
 cation, originate 
 
 Cells of the triohome often gemi- 
 nate or ternate in consequence 
 of their lateral multiplication, or 
 even forming transverse several 
 celled bands. Sheath large. Cells 
 surrounded with a, thick mem- 
 brane very prominent in the old 
 filaments. Hormogones origina- 
 ting ia lateral branchlets formed 
 of a single row of cells 
 
 i8 Filaments of the hormogones 
 much slenderer than the 
 principal filament, and origi- 
 nating in unilateral tufts . 
 
 10 SCTTONEMEJE 
 
 Oscillaria. 
 Trichodesmium . 
 
 A. B. 
 
 Microcoleu!. 
 
 Inactis. 
 A. B. 
 
 Lyngbya. 
 SympToca. 
 
 Plectonema. 
 . 11 
 
 A. B. 
 
 Stigonema. 
 
 . FKschera. 
 
NOSTOCRiE. 
 
 223 
 
 11 
 
 B. Triohomes formed mostly of a 
 single row of cells. Sheath slen- 
 der. Aquatic plants looking like 
 Tolypothrix . . . , . Haplosiphon. 
 
 ^Sheaths enclosing several triohomes . . . Cijstocoleus. 
 I Sheaths enclosing only a single trichome. 
 ■j Kamifications produced by the deviation of 
 the trichome, which emerges from the side 
 V. of the sheath A. B. 
 
 A. Ramifications usually geminate, pro- 
 
 duced by a fold of the trichome 
 which ruptures outside of the 
 sheath, and gives birth to two 
 filaments given off at a right 
 angle. Heterooysts scattered 
 here and there ' in the trichome 
 without any evident relation to 
 the ramifications 
 
 j3 Sheath very broad, forming 
 a transparent layer around 
 the trichome , 
 
 y Filaments agglutinated in 
 erect wick-like bundles 
 
 B. Eamifications rarely geminate, often- 
 
 times solitary, and originating at 
 a point where the continuity of 
 the trichome is interrupted by 
 heterooysts. One or several he- 
 terooysts placed directly above 
 each brauohlet .... 
 
 'Filaments agglutinated by a 
 more or [less firm mucilage. 
 Frond usually with a well de- 
 fined outline . . ' . 
 
 Scytonema. 
 
 Petalonema. 
 ymphyosiplwn. 
 
 Tolypothriai. 
 
 12 Caloteichej} 
 
 13 
 
 Filaments free, growing in small 
 tufts, or forming a turf of 
 considerable extent 
 
 "Heterooysts scattered. Eamifications very 
 irregular, arising from a fold in the tri- 
 chome, in the form of a T, where originate 
 two geminate filaments, distinct at the base, 
 but at a certain height transformed, for the 
 greater part, into a single filament, composed 
 of a single row of cells. Frond hollow, but 
 hard, folded and looking like a little Rivu- 
 laria, ........ 
 
 Heterooysts basal (placed at the base of the 
 principal filaments and branchlets). Ramifi- 
 cations produced by the transverse division 
 of the trichomes, the upper part of which 
 detaches itself and becomes a lateral branch- 
 let, while the lower part extending itself by 
 the side of its old tip makes a new extremity 
 similar to the first ..... 
 
 . 13 
 
 Calothrix. 
 
 SormacHs. 
 
 14 
 
 2 1 
 
224 NEilATOGEN^. 
 
 f Spores originatiug in the lower part of the 
 
 14 < trichome Glceotricha. 
 
 t Trichomes never prodnoing any spores . . . . .A. 
 
 A. Frond having a tendency to an 
 hemispherical or bladdery form. 
 Filaments exhibiting a disposition 
 to radiate from the base of the 
 frond RiMularia. 
 
 P Frond flat. Filaments erect, 
 
 parallel Isaetis. 
 
 Sab-tribe I. Psiloneme^. Filaments not attenuated into a 
 hair-lihe extremity. 
 
 Family I. NOSTOCB^. 
 
 Trichomes furnished with heterocysts, involved in a very 
 copious gelatin, more or less firm or diffluent, which is collected 
 into a variously expanded, or very often indefinite thallus, or 
 rarely with the mucilage quickly dissolved, subsolitary. — Borzi 
 Alg. Fico. p. 279. 
 
 Genus 94. NOSTOC. Faueh. (1803.) 
 
 Thallus gelatinous or membranaceous, girt by a more or less 
 firm periderm, definite, globose, or variously expanded. Tri- 
 chomes flexuously curved, irregularly interlaced, now and then 
 vaginate, joints globose or elliptical, distinct, or more or less 
 closely connected. Heterocysts terminal or intercalated, larger 
 or equal to the other cells. Spores equal to the heterocysts, or 
 a little larger, green, becoming bluish, olivaceous, or yellowish 
 brown. 
 
 The Nostocs consist of a more or less firm jelly, in which beaded fila. 
 ments are imbedded, consisting of chains of small, somewhat globose 
 simple cells. These filaments or trichomes are usually surrounded by a 
 sheath, which is often so delicate as scarcely to be visible, or it is almost 
 obsolete. The frond or thallus may be globose, discoid, lobed, or 
 irregular, with a more or less distinct outer layer forming a kind of 
 epidermis. 
 
 At irregular distances in the trichomes are larger cells, or heterocysts, 
 formerly regarded as spermatia, which differ In colour from the other 
 cells of the trichome. Individual cells become heterocysts uninfluenced 
 by any definite law at present demonstrated. 
 
 Increase in the filaments is caused by division of the cells in the longi- 
 tudinal direction, whereby the trichome is constantly being lengthened, 
 and new cells added, which lie in the mucilage. 
 
 Thuret hag explained the process by which new plants originate from 
 
NOSTOOBJi. 225 
 
 fragments of the triohome which he terms hormogones. The mucilage of 
 old plants being softened, portions of the threads which lie between tho 
 heterooysta are detached and escape from the mucilage, whilst the hetero- 
 oysts remain behind. These escaped fragments become endowed with 
 motion, similar to that observed in Osciltaria. The cells of the hormo- 
 gone increase by division at right angles to the filament, and ultimately 
 separate longitudinally, becoming the centres of new plants. 
 
 Besides the reproduction by hormogones, certain special cells of the 
 trichome enlarge and become converted into spores, which germinate and 
 produce new plants, but no evidence of sexual reproduction has yet been 
 adduced. 
 
 Messrs Bornet and Thuret have subdivided the genus Nostoc into 
 eight groups, of which two are not represented in Britain. The 
 following is their synopsis, with the British species printed in small 
 capitals. 
 
 I. INTKICATA. Aquatic species. Fronds soft, gelatinous without deter- 
 
 minate form, often floating. 
 
 A. Trichomes forming irregular masses, de- 
 
 prived of the general mucilage. 
 Circumvolutions of trichome compact and 
 
 indistinct 1. hederid^. 
 
 Circumvolutions of triohome distinct . . 2. tenuisdmum. 
 
 B. Trichomes involved in mucilage more or 
 less abundant. 
 
 u Trichomes flexuous, aggregated ; joints 
 
 short and close together ; sheaths ub. 
 
 coloured, very refractive . . .3. linckia. 
 /3 Trichomes loosely interwoven, joints 
 
 of equal diameter, rather distant. 
 
 1. Spores subglobose, . . .4. piscinalb. 
 
 2. Spores oval. 
 
 * Mucilage soft ; sheath none, 
 indistinct, or uncoloured . 5. CARNEUM. 
 ** Mucilage firm ; sheaths and 
 mucilage tinged with yellow at 
 the periphery . . . .6. nvulare. 
 
 II. Gblatinosa. Fronds soft and gelatinous ; adherent ; joints of 
 trichomes cylindrioally elongated in the young filaments. Spores 
 oblong, large. 
 
 A. Growing in watery or inundated places; 
 fronds thick, deformed. 
 
 a Trichomes heterogenous, composed of 
 two sorts of joints, one cylindrical, the 
 other cask-shaped or compressed spheri- 
 
 cal 7. SPONGIiBFOB,MB. 
 
 ^ Trichomes homogenous . . .8. gelatinoswm. 
 
 B. Plant terrestrial. Frond plane, applied to 
 
 the ground by the inferior surface . . 9. ellipsospoeum. 
 
 III. HtTMiPUSA. Terrestrial species. Fronds at first globose, then con- 
 fluent, and forming gelatinous cushions adhering to the substratum by 
 their lower face. Spores smooth. 
 
 A. Fronds in orbicular discs, or indefinite and 
 continuous. 
 
226 KEMATOGEN^. 
 
 a Spores measuring 'OOi x -008 mm. or more. 
 
 1. Sheaths confluent, trichomes scat- 
 tered, irregularly interlaced. 
 
 * Spores rounded oval . . 10. coUinum. 
 ** Spores oval . ... .11. muscobum:. 
 
 2. Sheaths well defined, and separable 
 by pressure, trichomes folded ver- 
 tically and parallel . . .12. Passmnianum. 
 
 p. Spores measuring -004 x -OOO mm. or more. 
 
 * Mucilage tolerably firm ; tri- 
 chomes olive. Spores oval . 13. HUIUpijsum:. 
 
 ** Mucilage soft, easily diffluent, 
 trichomes seruginous green. 
 Spores subglobose . . .14. ealcieola. 
 B. Fronds deformed, hollow ; joints spherical 
 compressed 15. foliaceum. 
 
 IV. CoinitTNiA. Terrestrial species Csometimes inundated). Fronds at 
 first globose, then becoming tongue-shaped, plane, or irregular, not 
 adherent. 
 
 Adalt frond suborbicular, folded, undulate, 
 entire or lobed, often perforated ; joints 
 spherical-compressed, uniform . . .16. coiniUNB. 
 
 V. Sph.«;eica. Fronds globose or subglobose (often becoming irregular 
 when they grow large), limited by a firm and resisting peridermic 
 coating. 
 
 A. Terrestrial species, or sometimes inundated. 
 
 a Trichomes not fusiformly swollen be- 
 tween the heterooysts. 
 
 1. Fronds attaining 1 m. and more. 
 Trichomes torulose. 
 
 * Frond firm, trichomes com- 
 pact, joints cask-shaped, or 
 compressed sphaerical close to- 
 gether, uniform ; spores oval, 
 
 smooth 17. sph:.s)bicum. 
 
 ** Fronds soft, trichomes much 
 spaced out, of unequal size, 
 joints nearly sphaarical, sheaths 
 often coloured, contrasting 
 with the generally uncoloured 
 mucilage ; spores oval, smooth 18. bupestee. 
 2 Fronds very small, punctiform, not 
 attaining 1 mm. 
 
 Trichomes large; joints cylin- 
 drical, a little constricted at the 
 point of junction ; spores glo- 
 bose, smooth . . . .19. STACBOSPOBUir. 
 $ Trichomes fusiformly swollen between 
 the heterooysts ; joints dissimilar, the 
 one kind straight and elongated, the 
 other larger and sphaerical ; spores 
 sphaerical, rough 20. spTueroides. 
 
 B . Aquatic species (colour blue, or approach- 
 ing to blue). 
 
 a Trichomes dissimilar, unequal ; joints 
 of two forms, the one (young) elon- 
 gated, the other large, sphaerical, often 
 filled witti opaque granules . . .21. ccebulbfm- 
 
NOSTOCB^. 227 
 
 ;8 Triohomes homogenous, regular. 
 
 1. Frond very small ; triohomes very 
 
 compact 22. minvtissimum. 
 
 2. Frond attaining 2.10 mm. 
 
 * Joints sphEerioal, compressed . 23. gregarium, 
 ** Joints discoid, very compact . 24. edvle. 
 
 3. Fronds attaining the size of a nut 25. petjnifoemb. 
 
 VI. Veerucosa. Aquatic species. Fronds rounded or discoid, at first 
 full, then hollow, limited at the circumference by a firm and tough 
 periderm. Trichomes thin, very regular, spaced out and a little 
 flexuous at the centre, more compact, and very distorted at the peri- 
 phery. 
 
 a. Fronds subglohose or warted. Mucilage 
 tolerably soft. Trichomes medium com- 
 pact, and often deprived of sheaths at 
 
 the periphery 26. VEEEUCOSrar. 
 
 b. Fronds at first discoid or tongue-shaped, 
 a little ovoid, hard ; trichomes radiating 
 regularly from the centre to the circum- 
 ference and there forming a very dense 
 
 layer 27. parmelioides. 
 
 VII. Zbtteestedtiana. Aquatic species. Fronds sphserical, hard, 
 tuberculose, divided into radiating separable 
 
 lobes . . 28. Zetterstedtii. 
 
 VIII. Flagellifoemia. Terrestrial species. Fronds forming thongs, 
 linear straight, and very long. 
 
 Frond linear or setaceous, subdichotomous 
 trichomes longitudinally parallel . . 29. fiagdliforme. 
 
 I. Inteicata. Species aquatic, fronds soft, gelatinous without 
 determinate form, often floating. 
 
 Nostoc Iiinckia. (Roth.) Born S; Thw. Notes Alg. p. 86, t. 28, 
 
 /. 1-12. 
 
 Fronds lobed, multipartite, free swimming, as large as a 
 walnut, lobes elongated and anastomosing, seruginous green, at 
 length becoming brownish. 
 
 Trichomes flexuous, aggregated, joints short and close, 
 sphserical, or sphKiical compressed, sheaths uncoloured, very 
 refractive. Heterocysts slightly oblong. Spores subglohose or 
 oval. 
 
 Size. Joints '0035 mm., heterocysts "OOS-'OOe mm. diam., 
 spores (in form intricatum) subglohose '0065 x -009 mm. 
 
 Rivularia Linkia, Eoth. Neue Beitr. p. 263. 
 
 Nostoc confusum, Ag. Syst. Alg. p. 22. 
 
 Monormia intricata. Berk. Glean, t. 18. Hass. Alg. 286, t. 
 75, f. 11. Kalfs. Ann. Nat. Hist. 1850, p. 326, t. 8, f. 1. 
 
 Anahaena intricata, Kutz. Phyc. Germ. 171. Rabh. Alg. 
 Eur. ii., 183. 
 
 Anabaena flos-aqvcB, Rabh. Alg. Sachs. No. 27. 
 
228 NEMATOGENJ5. 
 
 Nostoc piscinale, Wittr. & Nord. Alg. Exs. No. 195. 
 Nostoc inlricatum, Meneg. Nost. Ital. p. 122. Borzi Alghe 
 Fico. p. 2Sd. 
 
 In ditches (slightly brackish). 
 
 " Forming small roundish gelatinous masses, floating amongst different 
 species of Lemna in fresh water, but probably within the influence of the 
 tide, and also amongst Enteromoi'p'lui intestinalis, and even within the 
 frond in brackish water. The plant is at first of an olive yellow gradually 
 assuming a greener tint, and when dried of a deep verdigris. Very 
 gelatinous, delicately branched, the branches very flaccid. Under a high 
 magnifier the whole plant is evidently composed of gelatine, in the centre of 
 which runs a single moniliform filament, following the ramifications, and 
 in its progress curling to and fro repeatedly across the thread, the joints 
 beinj nearly globular. The specimens from the interior of Enteromorpha 
 are paler, and have longer joints amongst the globular ones." — Berlceley. 
 
 Plate LXXXIX. Jig. 1. Nostoc lAnkia (intricata) nat. size, after 
 Berkeley. 
 
 Fig. 2. Nostoc completely developed, composed of the interlacings of 
 a single trichome X 350. 
 
 Fig. 3. Portion of trichome, spores arrived at complete maturity X 650. 
 
 Fig. 4. a, spore commencing to germinate ; b, e, d, e, spores in 
 germination more or lass advanced x 660. 
 
 Fig. 5. Germinating filament changed into a hormogone X 650. 
 
 Fig. 6. Free hormogone X (JoO. 
 
 Fig. 7. Motile trichomes segmenting in fragments, of which each 
 constitutes a hormogone. 
 
 Fig. 8. Immovable hormogone commencing to develope X 640. 
 
 Fig. 9. Development of hormogones X 650. 
 
 Fig. 10. Group of spores germinating X 350. 
 
 Fig. 11. Chaplets of spores obtained by cultivation in germination X 
 650. Figs 2 to 11. After Bomet. 
 
 Nostoc piscinale. Kutz. Tab. Phyc. n., t. 11, /. 3. 
 
 Fronds attached or free swimming, bullate and tuberculate, 
 verdigris green, rarely rufescent, becoming olivaceous by age. 
 
 Trichomes loosely interwoven, joints equal in diameter, rather 
 distant. Spores subglobose. 
 
 Size. — Joints •0037-'004 mm., heterocysts '006 mm., spores 
 •007 X -008 mm. 
 
 Born. & Thuret Notes Alg. ii., 90. 
 
 Nostoc lacustre, Eutz. Tab. Phyc. ii., t. 11, f. 2. Eabh. Alg. 
 Eur. ii., 179. Borzi Alghe Fico. p. 281. 
 
 Nostoc aggluiinans, Kutz. Tab. Phyc. ii., t. 10, f. 1. Babh. 
 Alg. Eur. ii., 178. 
 
 In ditches. 
 
 Plate LXXXIX. fig. 12. Trichomes of N. piscinale X 400 ; fig. 13, 
 portion of trichome with heterocyst x 600 ; fig. 14, spores in course of 
 development, with mature spores X 600 ; fig. 15, spores in the early 
 stages of germination X 600, 
 
NOSTO0E.E. 229 
 
 'Nostoc caxneum. Aq. Syst. Alg. p. 22. 
 
 Frond indefinitely expanded, bullate and undulate, flesh 
 coloured, rufescent or pui'plish. 
 
 Trichomes loosely interwoven, joints equal, sheath none, in- 
 distinct, or uacoloured, spores oval. 
 
 Size. Joints -OOST-'OOi mm., heterocysts '006 mm. diam., 
 spores -006 X -009 mm. 
 
 Rabh. Alg. Eur. ii., p. 180. Born, and Thuret, Notes Alg. p. 
 91. 
 
 Nostoc variegaium, Harv. Man. 183. Kutz. Sp. Alg. 301. 
 Hass. Alg. p. 287, t. 74, f. 3. 
 
 Nostoc purpurascens, Kutz. Tab. Phyc. ii., t. 11, f. 4. 
 
 Nostoc rufescens, Ag. Syst. 22. Rabh. Alg. Eur. ii., 179. 
 
 On rocks. 
 
 "First collected in Iceland in 1836, growing on the face of a moist 
 bank over which water trickled. When recent it formed a soft gelatinous 
 mass, of a livid colour, bearing the closest resemblance, both in substance 
 and colour, to those gelatinous medusae which are cast ashore along the 
 coast." — Moore. 
 
 Plate XC. Jiff. 1. Nostoc carneum, natural size ; fig. 2, trichomes 
 X 400 ; fig. 3, development of spores X 600. 
 
 II. Gelatinosa. Fronds soft and gelatinous, adherent, joints of 
 
 triclwme cylindrically elongated in the young filaments. Spores 
 
 oblong, large. 
 
 Nostoc spongisefoirine. Ag. Syst. Alg. p_ 22. 
 
 Frond at first subglobose, then indefinitely expanded, be- 
 coming rather firm, pale seruginous or olive green, surface 
 tuberculated. 
 
 Trichomes heterogenous, composed of two sorts of joints, one 
 cylindrical the other cask-shaped, or compressed spherical. 
 Heterocysts globose. Spores smooth, oblong. 
 
 Size. Joints -004 mm., heterocysts ■007-'008 mm., spores 
 •006--007 X ■01--012 mm. 
 
 Born. & Thuret Notes Alg. p. 92. Rabh. Alg. Eur. ii. 1 78. 
 Kutz. Tab. Phyc. ii., t, 9, f. 4. 
 
 Nostoc inundatum, Kutz. Spec. Alg. 299. Rabh. Alg. Eur. 
 ii., 171. 
 
 Hormosiphon inundatum, Kutz. Tab. Phyc. ii., t. 27, f. 2. 
 
 Hormosiphon stagnalis, Kutz. Tab. Phyc. ii., t. 27, f. 3. * 
 
 Hormosiphon nutans, Kutz. Tab. Phyc. ii., t. 27, f. 4. 
 
 In wet or inundated places. 
 
 Plate XO. fig. 4. Nostoc spongioeforme, natural size; fig. 5) young 
 triohome ; fig. 6, mature trichome X 400 ; fig. 7, portion of mature 
 trichome X 600. 
 
230 NEMATOGEN^. 
 
 Nostoc ellipsospomm. (Desm.) MabK. Alg. Eur. n., 169. 
 
 Plant terrestrial. Frond plane, applied to the ground by the 
 lower surface, gelatinous, rufous brown. 
 
 Trichomes densely interwoven, pale seruginous green, joints 
 cylindrically elongated, loosely connected, sheaths broad, homo- 
 genous. Heterocysts elongated, elliptical, spores oblong, 
 smooth. 
 
 Size. Joints -004 mm., heterocysts -OOG-'OO? mm., spores 
 •006 X ■006--008 X -019 mm. 
 
 Bom. & Thuret Notes Alg. ii., 94, t. xxvii., fig. 7-11. 
 
 Hormosiphon ellipsosporum, Desm. PL Crypt. No. 133. 
 
 On the ground amongst moss. 
 
 Plate XC. Jig. 8. Trlchome of Nostoc eUipsosporum producing spores 
 X 400 ; fig. 9, portion of tiioliome which at one extremity exhibits the 
 sheath ; fig. 1 0, trichome with the greater part of the joints transformed 
 into spores ; fig. 1 1, young trichome from germinating spore. Figs. 9, 
 10, 11, X 600 diam. after Bornet. 
 
 III. HuMiFusA. Species terrestrial. Fronds at first globose, 
 
 then confluent, and forming gelatinous patches adhering by their 
 
 lower face. Spores smooth. 
 
 Nostoc muscoram. Ag. Disp. Alg. p. 55. 
 
 Frond dark green, foliaceous, tuberculate, opaque. 
 
 Trichomes diffused, irregularly interwoven, pale seruginous 
 green. Sheaths confluent. Heterocysts sphserical, usually 
 intercalated. Spores oval. 
 
 Size. Joints -0035 mm., heterocysts "005 mm., spores "006 
 X '01 mm. 
 
 Bom. & Thuret Notes Alg. p. 96, t. 27. Rabh. Alg. Eur. ii., 
 173. Eng. Fl. v., 399. Hass. Alg. 292, t. 74, f. 4. Gray 
 Arr. i., 351. 
 
 On calcareous rocks, and the mosses that cover them. 
 
 Plate XC. fig. 12, Nostoc mu^cm-um nat. size; fig. 13, trichome X 
 400; fig. 14, sterile trichome; fig, 13, fructifying trichome; fig. 17, 
 trichome with spores involved in sheath ; figs. 17, 18, spores germinating; 
 figs. 14-18, X 600, after Bornet. 
 
 Nostoc hnmifnsum. Cam. Eng. Fl. ii., 399. 
 
 Frond small, at first globose or subglobose, from the size of 
 a peppercorn, olive, then brownish, shining opaque when dry. 
 
 Trichomes olive, slender, vertically folded, sheaths well de- 
 fined. Heterocysts globose. Spores oval. 
 
 Size. Joints -0022 mm., heterocysts -003 mm., spores -004 
 X-006 mm. 
 
NOSTOCEiE. 231 
 
 Harv. Man. p. 184. Born. & Thuret Notes Alg. p. 99. 
 
 NostOG panetinum, Rabh. Alg. Eur. ii., 178. 
 
 Anabaena granulans, Kutz. Tab. Phyc. i., t. 94, f. 6. 
 
 Nostoc granulare, Rabh. Alg. Eur. ii., 163. 
 
 Nostoc tepidariorum, Braun. in Rabh. Alg. No. 2461, 2462. 
 
 On mosses and on walls in greenhouses, &c. 
 
 Plate XCl. fig. 1. Nostoc Tiumifusum, nat, sizej fig. 2, triohomex 
 400; fig. 3, portion of triohome x 600. 
 
 IV. CoMMUNiA. Species terrestrial. Fronds at first globose, 
 
 then tongue-shaped, plane or irregular. 
 
 Nostoc commune. Vauch. Conf. p, 222, t. 16, f. 1. 
 
 Adult frond sub-orbicular, folded, undulating, entire or lobed, 
 often perforated, olive, yellowish-brown, or becoming brownish. 
 
 Trichomes flexuous, loosely interwoven, pale blue-green. 
 Joints sphserical, compressed, uniform. Heterocysts globose. 
 
 Size. Joints, •0045--006 (usually -005) mm., heterocysts 
 ■007 mm. 
 
 Rabh. Alg. Eur. ii., 175. Hass. Alg. t. 74, f. 2. Borzi. 
 Alghe Fico. p. 284. Eng. Bot. i., t. 2556, pi. p. 1625. Eng. 
 Bot. i., t. 461. Relh. Cant. 441. Lightf. PI. Scot. 898. Purt. 
 Midi. Fl. ii., 612. Abbot. Bedf. 271. With. Arr. iv., 80. 
 Jenner Fl. Tunb. Wells, 190. Harv. Man. 183. Johnst. 
 Fl. Berw. ii., 262. Grev. Fl. Edin. 822. Mack. Hib. 245. 
 Plor. Dev. ii., 49. Eng. Fl. v., 398. Dickie Bot. Guide, 310. 
 
 Tremella nostoc, Linn. sp. 
 
 Nostoc ciniflonum. Born. & Thuret Notes Alg. ii., 102. 
 
 Nostoc foliaceum, Ag. Syst. Alg. p. 19. Hass. Alg. t. 76, 
 f. 2. Rabh. Alg. Eur. ii., 173. Eng. Fl. v., 399. Harv. Man. 
 183. Mac. Hib. 245. Dickie Bot. Guide, 310. 
 
 Nostoc arctum, Kutz. Tab. Phyc. ii., t. 7, f. 1. 
 
 Nostoc littorale, Kutz. Tab. Phyc. ii., t. 8, f. 1. 
 
 Nostoc prismaticum, C6s. in Rabh. Alg. Eur. ii., 169. 
 
 Nostoc rugosum, Kutz. Tab. Phyc. ii., t. 11, f. 1. 
 
 Nostoc salsum, Kutz. Tab. Phyc. ii., t. 8, f. 3. 
 
 On wet ground. 
 
 Plate XCI. fig. 4. Nostoc commune, nat. size ; fig. 5 triohome x 400 ; 
 fig. 6, portions of triohome x 600, fig. 7, portion of triohome. 
 
 V. SPH.aBBlcA. Fronds globose or subglobose (becoming irregular 
 when they grow large), limited by a firm and resisting peridermic 
 
 coating. 
 
 Nostoc sphsezicum. Vauch. Conf. 223, t. 16, /. 2. 
 
 Fronds firm, sphserieal, about the size of a pea, gregarious, 
 olive or bluish-green, or brownish, with a firm brownish or 
 colourless periderm. 
 
 2 K 
 
232 SEMATOGBK^. 
 
 Trichomes compact, densely interwoven at the periphery, 
 joints cask-shaped, or compressed sphaerical, close together, 
 uniform. Heterocysts subglobose. Spores oval, with a thick 
 tegument, smooth. 
 
 Size. Joints •004-"005 mm., heterocysts "006 mm., spores 
 •005 X -007 mm. 
 
 Born. & Thuret Notes Alg. p. 108. Eabh. Alg. Eur. No. 
 746. Harv. Man. 184. Gray Arr. i., 352. Eng. El. v., 400. 
 Hass. Alg. 289, t. 76, f. 5 (?). Dickie Bot. Guide, 310. 
 
 Nostoc vesicarium, Menegh. Nost. Ital. p. 108 (not Harvey). 
 
 Ulra pisifoi-mis, Huds. El. Ang. ii., 572. 
 
 In springs and mountain rivulets. 
 
 " Fronds from half a line to two lines in diameter, globular, firm, 
 smooth, solid, heaped on each other like a parcel of small shells. In- 
 ternal filaments rather thinly scattered through the mass." — CarmicTiael. 
 
 Plate XCJ. Jig. 8. Nostoc spJttericum nat. size ; fig. 9, trichome x 400 ; 
 fig. 10, portion of trichome x 600; fig. 11, spores x 600. 
 
 Nostoc xupestre. Kutz. Spec. Alg. p. 296. 
 
 Eronds soft, globose, olive, becoming brownish, often forming 
 an irregular crust. 
 
 Trichomes much spaced out, of unequal size, joints nearly 
 spherical, sheaths often coloured, contrasting with the generally 
 uncoloured jelly. Spores oval with a smooth tegument. 
 
 Size. Joints •005--008 mm., heterocysts "007 mm. 
 
 Eabh. Alg. Eiir. ii., 163. Thuret Notes Alg. p. 112. Borzi 
 Alghe Fico. p. 283. 
 
 Nostoc microscopicum, Carm. Harv. Eng. El. ii., 399. Harv. 
 Man. 184. Mack. Hib. 245. 
 
 On rocks, overrunning mosses, &c. 
 
 This species is mixed up by Hassall with Nostoc muscorum, if it be not 
 in reality the whole of that species, for there is some doubt whether N. 
 muscorum, as defined by Bomet and Thuret was known to him. 
 
 Tlate XCI. Jig. 12. Involved trichomes of ff. rupestre x 400 ; figs. 13, 
 14, 15, young plants in course of development x 400, after Borzi. 
 
 Nostoc maczospozum. Meneg . Mon, Nost. \W, t. Xi, f. 2. 
 
 Eronds very small, punctiform, aeruginous-green, or brownish- 
 olive. 
 
 Trichomes large, bluish-green, or brownish, joints cylindrical, 
 a little constricted at their junction. Sheaths broad, brownish 
 or yellowish-brown. Heterocysts globose. Spores globose with 
 a smooth tegument. 
 
 Size. Joints •008-'009 mm., heterocysts -OOg-'Ol mm. 
 
 Born & Thuret Notes Alg. p. 112. Eabh. Alg. Eur. ii., 163. 
 Hass. Alg. 293, t. 73, f. 1, 2. Borzi Alghe Fico. p. 283. 
 
NOSTOCE^ 
 
 233 
 
 Hormosiphon macrosporus, Kutz. Tab. Phyc. ii., t. 13, f. 1. 
 Diplocolon Heppii, Itzig. Phyc. Stud. t. 11, f. 8-12. 
 J^ostoe pi/reniacum,^iipa.rt. Bull. Soc. Bot. Fr. (1868.) 
 Nostoc ichthyon, Eabh. Alg. Eur. ii., 164. 
 
 On rocks among moss. 
 
 Plate XCU.figs. 1, 2. Involved trioliomes of N. macrosporum x 400 i 
 fig. 3, developmeat of hormogoue, x 400, after Borzi. 
 
 Nostoc cxzuleum. I/yngb. Uydr. Dan. t. 68, /. B. 
 
 Fronds, small, globose or subglobose (i to 4 lines) , fixed or 
 free swimming, usually gregarious, blue or greenisll-blue. 
 
 Tricbomes dissimilar, unequal, joints of two forms, the one 
 (young) elongated, the other larger, nearly sphserical, some- 
 times filled with opaque granules. 
 
 Size. Joints ■004--007 mm., heterocysts -008 mm. 
 
 Born. & Thuret Notes Alg. p. 114. Eabh. Alg. Eur. ii., 167. 
 Nord. & Wittr. Alg. Exs. No. 98. Grey. So. Crypt. Fl. 1. 131. 
 Hass. Alg. 293, t. 76, f. 11, t. 75, f. 10, t. 74, f. 1. Eug. Fl. 
 v., 400. HarF. Man. 183. Gray Arr. i., 352. 
 
 Nostoc ccBTulescens, Eabh. Alg. Eur. ii., 168. 
 
 Nostoc Itzigsohnii, Eabh. Alg. Eur. ii., 168. 
 
 On mosses and submerged plants. 
 
 Plate XCII. fig. 4. Plants of Nostoc cesrulmim natural size ; fig. 5. 
 trichomes x 400 ; fig. 6, portion of triohome x 600. 
 
 Nostoc pxunifozme. Ag. Bisp. Alg. p. 45. 
 
 Frond from the size of a pea to that of a damson, or larger, 
 olive or dark seruginous-green, when old becoming blackish- 
 brown, with a coriaceous periderm, and watery within. 
 
 Trichomes loosely interwoven, joints subglobose, compressed, 
 closely connected. Heterocysts globose, usually terminal. 
 
 Size. Joints ■004-'005 mm., heterocysts ■006-'007 mm. 
 
 Born. & Thuret Notes Alg. p. 116. Eabh. Alg. Eur. ii. 
 Kutz. Tab. Phy. ii., t. 4, f. 4. Witt. & Nord. Alg. Exs. 97, 
 276. (?) Berk. Glean, t. 19, f. 2. Hass. Alg. i!91, t. 76, f. 
 3,4. Eng. Fl. v., 399. Harv. Man. 183. Gray Arr. i,, 352. 
 
 Ulva pruniformis, Huds. Ang. ii., 572. Abbot. Bedf. 274. 
 With. Arr. iv., 120. Hull. Br. Fl. 310. 
 
 Nostoc coccymelon, Kutz. Tab. Phyc. ii., t. 4, f. 3. 
 
 In freshwater pools, rivulets, &c. 
 
 Plate XCII. fig. 7. Nostoc pnmiforme, natural size ; fig. 8, triohome 
 X 400 ; fig. 9, portion of triohome, with spores in course of formation 
 x600. 
 
234 NEMATOGEN^. 
 
 VI. Verrucosa. Species aquatic. Fronds rounded or discoid, 
 filled, then hollow, ivith a tough periderm. 
 
 Nostoc venacosnin. Vaiich. Caitf. 225, t. xti., /. 3. 
 
 Fronds subglobose or nodulose, warted, brownish-green, jelly 
 tolerably soft, limited at the circumference by a firm and tough 
 periderm. 
 
 Trichomes slender, somewhat compact, spaced out, and a 
 little flexuous at the centre, more compact and distorted at the 
 periphery, where they are often deprived of sheaths. Joints 
 subglobose, closely connected. Heterocysts spherical. 
 
 Size. Joints 'OOS-'OOSS mm., heterocysts -006 mm., spores 
 •005--007 mm. 
 
 Bom. & Thuret Notes Alg. p. 117. Thur. Ann. Sci. Nat. 
 1844, ii., t. 9, f . 1-5. Rabh. Alg. Eur. ii., 176. Borzi Alghe 
 Fico. p. 284- Hass. Alg. 291, t. 76, f. 1. Grev. Fl. Ed. 323. 
 Hook. Fl. Scot, ii., 74. Mack. Hib. 245. Fl. Dev. ii., 49. 
 Gray Arr. i., 351. Kutz. Tab. Phyc. ii., t. 9, f. 11. Eng. Fl. 
 v., 400. Har7. Man. 183. Dickie Hot. Guide, 310. 
 
 Nostoc irregulare, Wartm. in Rabh. Alg. Eur. ii., 167. 
 
 Nostoc nivale, Kutz. Tab. Phyc. ii., t. 8, f. 4. 
 
 Nostoc Peloponnesiacum, Kutz. Tab. Phyc. ii., t. 9, f. 3. 
 
 Nostoc sphmricum, Meneg. Nost. Ital. 110. Kutz. Tab. Phyc. 
 ii., t. 3, f. 2. 
 
 Tremella verrucosa, Huds. Fl. Ang. Lightf. Fl. Scot. 898, 
 With. Arr. iv., 81. 
 
 In streams, attached to stones. 
 
 Plate XCII. Jig. 10. Nostoc verrticosvm, natural Bize; fig. 11, tri- 
 chomes X 400 ; figs. 12-13, portions of trichome ; fig. 14, honnogones 
 nndergoing division ; figs. 12 to 14 x 600, after Thuret ; fig. 16, spores; 
 fig. 17, spore in germination x 600. 
 
 Gencts 95. ANAB&ENA. £ory. (1823.) 
 
 Trichomes moniliform, without sheaths (or rarely vaginate), 
 composed of sub-globose cells, some of which become changed 
 into globose or elongated spores, usually yellowish brown or 
 golden brown. Heterocysts intercalated in the trichomes. 
 Spores originating in ceUs not adjoining the heterocysts. — 
 Bom. and Thur, Notes Alg. 
 
 Eecent authors have modified this genus in different directions. Borzi 
 does not adopt the same limitations as Thuret, neither does Kirchner or 
 Professors Nordstedt and Wittrook. 
 
NORTOCB^. 235 
 
 Professor Wittrook suggests that the geuns Anabaena should be 
 divided iato four sab-genera, under the following designations : — 
 
 Sub-Gen. 1. Tzichozmus. Spores globose, or subglobose, hetero- 
 oysts intercalated, distant from the spores. 
 
 Sub-Gen. 2. Dolichospezmum. Spores subellipsoid or sub- 
 cyliudrioal, heterooysts as in Tric/wrmus. 
 
 Sue-Gen. 3. Sphszozyga. Spores subellipsoid or subcylindrioal, 
 heterooysts intercalated, proximate to the spores. 
 
 Sub-Gen. 4. Cylindzospezmum. Spores subellipsoid or cylindrical, 
 heterooysts for the most part terminal and proximate to the spores. 
 
 Anabaena flos-aquee. Kutz. Tab. Phyc. i., t. 94. 
 
 Free swimming, membranaceous, blue-green. Trichomes more 
 or less curbed, often circinate, joints sphserical, or from mutual 
 pressure elliptic or quadrate. Heterooysts intercalated, elliptical. 
 Spores globose. 
 
 Size. Cells -OOiS-'OOG mm; heterocysts •012--014 mm. 
 long ; spores -OOS-'Ol mm. 
 
 Eabh. Alg. Eur. ii., 182. Kirch. Alg. ScU. 235. 
 
 Nostoc flos aquce, Lyngb. Hydro, t. 68, f. D. 
 
 Trichormus incurvus, Allm. Ann. Nat. Hist, xi., 163. 
 
 vwr. cizcinalis. Kirch. Alg. Selil. 23S. 
 
 Tricliomes more circinate, and joints rather larger. 
 Size. Cells •007-'01 mm. ; spores ■012-014 mm. diam. 
 Anabaena circinalis, Eabh. Alg. Eur. ii., 183. 
 Anabaena spiralis, Thompson Ann. Nat. Hist. (1846) v., 
 p. 81. 
 
 Trichormus spiralis, Ealfs Ann Nat. Hist. (1850) p. 328. 
 
 In ponds, moor pools, &c. ^ 
 
 Plate XOni. fig. 1. Trichomes X 40o diam. ; i Trichormus spiraUs 
 after Balfs ; c var. circinalis, trichomes x ^00. 
 
 Prom the description and figure given by Ralfs, under the name of 
 Trichormus spiralis, we have no doubt that Thompson's Alga, which 
 himself termed Anaiaena spiralis, was the variety circinalis of this 
 species, although Hassall's figure and interpretation is entirely different. 
 The account •which Thompson gives of his " Alga which colonrs Bally- 
 drain Lake," is as follows : — 
 
 " On visiting the lake (July 15) to-day I found that the whole body of 
 water was tinged with a dull faintly glaucous hue. On going out in a 
 boat to ascertain the cause of this appearance, I saw that the water was 
 everywhere filled with extremely minute particles, which might be com- 
 pared to the motes in a sunbeam. To the unassisted eye they seemed 
 as delicate as the finest human hair, and of a spiral form. On enquiry 
 I learned that the appearance had been observed only for the last four 
 or five years, and for about three mouths in each year. One of my 
 friends had looked upon its approach with dread, as it interfered so 
 much with his angling, that during the period of its continuance this 
 spot had to be abandoned." Subsequently the plant was observed as 
 
 2 L 
 
236 NEMATOGEN^. 
 
 late as the 27th September, but on October 7th all had disappeared. In 
 the following year the Alga was seen first on the 3rd of July, and last 
 on the 23rd of September. 
 
 "The specimens obtained were invariably of similar breadth, and 
 rarely presented more than fonr spiral tnrns, and when of this size were 
 l-50th of an inch in length. The species at first, when mingling with 
 the water, is of a dark green colonr, when in calm weather it ascends to 
 the surface in separate particles it appears pale green ; when it does so 
 era masse (the earliest symptoms of decay) it is of a pale blue, and in the 
 last stage of decomposition ferraginons. When two of the spiral 
 portions come in contact they have an elastic power, by which they can, 
 though slowly, disentangle themselves, and separate foom each other." 
 
 Anabaena Tatiabilis. Kutz. Phyc. 6en. 
 
 Gelatinous, submembranaceous, deep blue-green. Trichomes 
 slightly flexuously curved, almost parallel, verdigris green, joints 
 globose or elliptic, compressed or depressedly subcylindrical, 
 1-1^ time.s longei' than broad ; heterocysts intercalated, paler ; 
 spores numerous, seriate, ellipsoid, golden tawny, with a rather 
 thick membrane. 
 
 Size. Cells -OOSS-'OOi mm. ; heterocysts -007 mm. ; spores 
 •00801 X •012 mm. 
 
 Sphwrozyga Thwaitesii, Harv. Phyc. Britt. t. 113, B. 
 
 Sphmrozyga variabilis, Kutz. Tab. Phyc. i., t. 96, Babh. Alg. 
 Eur. ii., 193. 
 
 Triehormus rectus, Ralfs Ann. Nat. Hist. (1850) t. 8,f. 6. 
 
 Anabaena licheniformis, Hass. Alg. 82, t. 75, f . 4 ? 
 
 Triehormus Thwaitesii, Ralfs Ann. Nat. Hist. (1850) p. 
 329, t. 8, f. 4. 
 
 In ditches. 
 
 It forms thin gelatinous dark green patches either on the damp soil 
 covered at springtides, or at the bottom of brackish ditches and pools. 
 
 Plate XCJII. Jiff. 2. Trichomes X 400, with heterocysts and spores. 
 Anabaena Hassallii. Nord. and Wittr. Alga JSxs. 
 
 Trichomes equal, curved, often circinate, interwoven in a thin 
 blue-green stratum, joints globose or more or less compressed, 
 delicately granular ; heterocysts sphajiical, colourless, interca- 
 lated without order ; spores oblong cylindrical, single or in pairs, 
 distinctly curved, dark blue green, densely granulated, 1^-2|^ 
 times as long as broad. 
 
 Size. Cells -008 mm. ; heterocysts •009-'01 mm. ; spores 
 •012 X 025 mm. 
 
 Sphcerozyga Hassallii, Rabh. Alg. Eur. ii., 195. 
 
 Anabaena Jlos-aquce, Hass. Alg. 282, t. 75, f. 2, Harv. Man. 
 p. 186. 
 
 Dolichospermum Thompsoni, Ann. Nat. Hist. (1850), t. 9, 
 f. 3. 
 
NOSTOOEJ!. 237 
 
 Anabaena circinalis, Phillips iu Grevillea ix,, p. 4, t. 134, 
 figs. «,/, 5-. 
 
 In ditctes with Confervce, and floating on lakes. 
 
 " Floating like powdered verdigris on mountain IooIls." This species 
 seems to be variable in the form and size of the spores, and in the number 
 of vegetative cells which oocnr between the heterooysts and spores. 
 Wittrook has figured varieties in which two, or even sometimes one, 
 cell intervenes between the heterocyst and spore, alluding to the fact 
 that in English specimens they are sometimes in juxtaposition. Al- 
 though technically the Shropshire specimens "would seem to belong to 
 SphcBrozyga, yet in all other features they agree so well with this species 
 that we have cited them here as abnormal forms of the present species. 
 
 Plate XO III. Jig. 3. Portions of trichomes with heterooysts and 
 spores X 400 ; b, after Ealfs ; c, after Phillips. 
 
 Anabaena Kalfsii, (Eutz.') 
 
 Forming extensive strata of a velvety rich dark green colour, 
 sometimes verging towards verdigris green. 
 
 Trichomes moniliform, joints sphserical. Heterooysts ellip- 
 tical, spores elliptic or cylindrical, one or two in each series 
 not contiguous to the heterocysts. 
 
 Size. Cells -004 mm. diam. Heterocysts -OOS-'OOe X 008 
 mm. Spores -OOS-'Ol x •022--08 mm. 
 
 Sphmrozyga Balfsii (Thw.) Eabh. Alg. Eur. ii., 193. Kirch. 
 Alg. Schl. 237. 
 
 Dolichospermum Raljsii, Ann. Nat. His. 1850, t. 9, f. 2. 
 
 Cylindrospermum Balfsii, Kutz. Tab. Phyc. t. 98, f. 7. 
 
 In bogs and rivulets. 
 
 " Distinguished from A . irusqualis by its elliptical heterocysts (which 
 are comparatively less broad), by its more orbicular ordinary joints, and 
 by having fewer spores." — Salfs. 
 
 Plate XCIV. fig. 1. Trichomes with heterocysts and spores X 400 
 diam, 
 
 Anabaena Smithii. (7/jk).) Noo'd. ^ Wittr. Alg. Etes. No. 197. 
 
 Trichomes straight, each included in a definite gelatinous 
 sheath ; joints subsphserical, compressed, about as long as wide ; 
 heterocysts subsphserical somewhat barrel shaped, half as wide 
 again as the joints, puncta very distinct ; spores cylindrical, very 
 unequal in length, with the ends rounded and somewhat trun- 
 cate. 
 
 Size. Cells •004--006 mm. diam. Heterocysts -OOS-'OOg x 
 •009--013 mm. Spores ■009--012 x •02--04 mm. {Wittrock.) 
 
 Dolichospervium Smithii, Thwaites Ann. Nat. Hist. 1850, t. 9, 
 f. 4. 
 
 In boggy pools with other Algse. 
 
238 NEMAT0GENJ3. 
 
 " Immediately diatinguisliable from its congeners on account of its 
 possessing a definite gelatinous sheath to each of its filaments, which 
 are of smaller diameter than those of any other species of DoUchosper- 
 mum. The ordinary cells are subspherical, somewhat compressed, and 
 of less diameter than the heterocysts, which are barrel-shaped, and 
 with very distinct puncta. The numerous spores, which are about twice 
 the diameter of the ordinary cells, are elongated and cylindrical, very 
 variable in length and in the number which occur together, and their 
 ends are slightly truncate." — Ralfs. 
 
 Plate X.C1I1. fig. 1. Portions of trichomea with heterocysts and 
 spores X 400 ; fig. a, from Scandinavian specimens ; fig. 6 from British 
 specimens. 
 
 Anabaena oscillaiioides. Bmy. Dict.Bist. Nat. 
 
 Forming a bluisL green stratum. 
 
 Tricliomes elongated flexuous, joints subquadrate, distinct ; 
 heterocysts barrel-shaped or elliptic. Spores oval, catenate, 
 somewhat larger than the vegetative cells. 
 
 Size. Cells •004--005 x •004--006 mm. Heterocysts -006- 
 •008 X •007--009 mm. Spores •007--008 X •008-'012 mm. 
 (Wittrock.) 
 
 Nord. & Wittr. Alg. Ex. No. 196. 
 
 Sphcerozyga oscillarioides, Kutz. Sp. Alg., p. 291. Borzi. 
 Alg. Fico. 286. 
 
 Trichormus oscillarioides, Ralfs in Ann. Nat. Hist. 1850, p. 
 329, t, 8, f. 5. 
 
 In brackish ditches. 
 
 " It differs from A. Thrvaifesii by its more quadrate ordinary cells, and 
 by its smooth and elliptical heterocysts." — Ralfs. 
 
 Plate XOIII. fig. 6. Portions of triohomes with spores and hetero- 
 cysts X 400. 
 
 Anabaena Thwaitesii. (Ralfs.) 
 
 Trichomes moniliform, straight or nearly so, joints quadrate. 
 Heterocysts oblong sub-quadrate, hardly exceeding the joints 
 in diameter. Spores numerous, cylindrical with truncate ends, 
 very variable in length. 
 
 Size. Cells ■006--007 mm. Heterocysts -008 x '01 mm. 
 Spores •01--012 X ■025--03 mm. 
 
 Dolichospermum Thwaitesii, Ealfs Ann. Nat. Hist. 1850, 
 837, t. 9, f. 5. 
 
 In freshwater pools, and brackish ditches. 
 
 Allied to A. Smithii, but its filaments are not included in a definite 
 gelatinous sheath. Its filaments are also stouter, and there is a differ- 
 ence in the form of its cells. The heterocysts are quadrangular, and 
 hardly exceed in diameter the ordinary cells. The cylindrical truncated 
 spores are numerous, many in a chain, and variable in length, about 
 twice the diameter of ordinary cells. 
 
 Plate XCIII. fig. 5. Portiong of trichomes with heterocysts and 
 spores X 400. 
 
NosTocE^. 239 
 
 Uncertain Species. 
 Anabaena insequalis. (fialfs.) Brawn,., in Uii. 
 
 Forming extensive strata consisting of thick gelatinous masses 
 of a deep green colour. 
 
 Trichoraes stout, moniliform, elongated, joints distinct, at first 
 quadrate, finally orbicular, with granular contents. Heterocysts 
 globose, broader than the ordinary joints, occurring at short 
 intervals. Spores 3-4 times longer than broad, with truncate 
 ends, in chains of two to five. 
 
 Size. Not determined. 
 
 Dolichospermum inmguale, Ralfs Ann. Nat. Hist. 1850, 335, 
 t. 9, fig. 1. 
 
 Sphoerozyga incequalis, Kutz. Tab. Phyc. i., t. 96. Rabh. 
 Alg. Eur. ii., 194 ? 
 
 In boggy pools. 
 
 We have seen no specimens of this, or of Kutzing's Sphisrozyga 
 intsqualis, and therefore cannot pronounce on their identity. Mr. Salfs 
 sajs that " this plant forms extensive strata, composed of thick 
 gelatinous masses of a deep green colonr. Filaments elongated, con- 
 sisting of from 100 to 200 cells, and, being stouter than in most species 
 belonging to this genus, visible to the naked eye. Ordinary cells dis- 
 tinct, quadrate in immature specimens, but at length nearly spherical, 
 appearing punctate on account of the scattered granular matter which 
 they contain. Vesicular cells (Heterocysts) spherical broader than the 
 ordinary joints and occurring at short intervals. Spores 3 to 4 times 
 longer than broad, with triincate ends ; in chains of from two to five 
 members." May be known from A. Ral/sii by its spherical heterocysts 
 and catenate spores. 
 
 Plate XCIII. Jig. 4. Trichomes with heterocysts and spores X 400 ; 
 after Balfs. 
 
 Genus 96. APHANIZOmENON. Morren. (1839.) 
 
 Thallus membranaceous, free swimming, bright blue, blue 
 green, or becoming olive. Trichomes medium size, a little 
 attenuated towards the apex, agglutinated parallelly and very 
 densely in fascicles, joints cylindrical, very closely connected, 
 pale blue, nearly colourless and delicately granular. Spores 
 elortgated, cylindrical, rounded at the ends, pale blue, or some- 
 what olive, exospore thin, quite smooth. Borzi Alg.Ficochrom. 
 p. 279. 
 
 Thuret places this genus next to Anahaena, but, in the absence of 
 heterocysts, it seems that its proper place would be in Lynghya, allied to 
 Oscillaria. We have retained it here, in preference to altering the " key 
 to the genera," which is given ou page 221. 
 
240 NEUATOGENJS. 
 
 Aphanizomenon flos-aquae. Ralfs Ann. Sai. Hist. t. 9,/. 6. 
 
 Floating, forming a pale or dark blue green stratum on the 
 surface of the water. Trichomes very thin, nearly straight, 
 aggregated in membranaceous flakes which readily separate, 
 either distinctly or indistinctly articulated, very pale blue or 
 colourless. Joints cylindrical, about as long as broad, slightly 
 granular. Spores more or less elongated cylindrical, 6-12 times 
 as long as broad, granular. 
 
 Size. Cells •003--004 mm. diam. Spores -005 x -OS-Oi 
 mm. 
 
 Allman, Quart. Journ. Micr. Sci. 1855, p. 21, t. 3. 
 
 Byssus flos-aqum , Linn. Spec. Plant. (1753) No. 1168. 
 
 Limnochlide flos-aquoB, Kutz. Tab. Pliyc; i., t. 91, f. 2, a. 
 
 Aphanizomenon incurvum, Morr. Bull. Brux., 1839, Harv. 
 Man. 145, Hass. Alg. 280, t. 76, f. 6. 
 
 Sphwrozyga Jlos-aquce, Rabh. Alg. Eur. ii., 195. 
 
 In ditches, ponds, and meres. 
 
 One of the species of Algae which contribute to the phenomena cha- 
 racterized as " breaking of the meres," Professor Allman thinks that he 
 has observed heterocysts (see Micr. Journ. p. 22), but this is not con- 
 firmed. 
 
 Plate XCIY. fig. 1. o, Trichomes in bundles, X 200 ; J, Trichomes, 
 with spores X 400. 
 
 Genus 97. SPB2:R0ZTGA. {Ag) Ralfs. (1850.) 
 
 Trichomes involved in an amorphous, often very quickly 
 diffluent, mucilage, rarely vaginate, agglutinated in an inde- 
 finite gelatinous stratum ; joints sphserical, elliptical or oblong, 
 transversely compressed and often quadrangular. Heterocysts 
 intercalated, binary, or soKtary. Spores originating in cells 
 placed on each side of the heterocysts. 
 
 Spheeiozyga Cazmichaeli. Earv. Phyc. Pritt. t. 113, 
 
 Stratum thin, of a dark or bluish green colour when recent, 
 but opaque and glaucous when dry. Trichomes moniliform, 
 with tapering extremities ; joints distinct, somewhat quadrate. 
 Heterocysts sphaerical. Spores oblong. 
 
 Size. Cells •0035--0045 mm. Heterocysts -006 mm. diam. 
 Spores -OOS-'Ol x •018--025 mm. 
 
 Kutz; Tab. Phyc. i.,t. 99, f. 4. Ralfs Ann. Nat. Hist. 1850, 
 t. 8, f. 7. Rabh. Alg. Eur. ii., 191. 
 
 Belonia tondosa, Carm. Eng. Fl. v., 379. Harv. Man. 167. 
 
 On damp soil in salt marshes flooded at spring tides, in 
 brackish ditches, &c. 
 
NOSTOCB^. 241 
 
 " The best distinctive mark of this species is the subacute extremities, 
 combined with the short filament and littoral habitat. There are rarely 
 more than one or two groups of enlarged cells, when only one is present 
 it is situated near the centre of the filament. I believe that the attenuated 
 extremities are constant, at least in the young plant, unless the filament 
 has been broken." — Ualfs. 
 
 Plate XOIV. fig. 3. Portions of tricliomes with heterooysts and 
 spores X 400. 
 
 Sphsezozyga Bxoomei. Thwaites in Harv. Phyc. Britt. 
 
 Stratum bluisli or yellowish green. Trichomes moniliform, 
 joints subsphgerical. Heterocysts smooth, subquadrate, rather 
 longer than wide. Spores numerous, elliptical, twice as long as 
 wide, not much exceeding in width the joints, commencing to be 
 formed on either side next to the heterocysts. 
 
 Size. Cells -004 mm. Heterocysts "005 X '006 mm. 
 Spores -008 X -016 mm. 
 
 Thwaites in Harv. Phyc. Britt. t. 173, fig. A. Ralfs Ann. 
 Nat. Hist. (1850) t. 8, fig. 10. 
 
 On dead leaves of Myriophyllum in brackish ditch. 
 
 " The gelatinous matrix is firmer than in many species of this genus. 
 The numerous spores in each series distinguish it from every other species 
 I am acquainted with." — Balfs. 
 
 Plate XCIV. fig. 4. Portions of trichomes, with heterooysts and 
 spores X 400. 
 
 Species imperfectly Icnown. 
 Sphaerozyga Berkeleyana. Thwaites in Earv. Phyc. Britt. 
 
 Young trichomes included, one or several together in a de- 
 fined mucous sheath. Joints sphrerical, compressed. Hetero- 
 cysts sphaeroidal, slightly compressed. Spores usually two on 
 each side of the heterocysts, large, twice the width of the joints, 
 oblong, half as long again as wide, becoming brown when 
 mature. 
 
 Size. Cells about ■006-'007 mm. Spores about -012 x 
 ■015 mm. 
 
 Thwaites in Harv. Phyc. Britt. t. 173, fig. B. Ealfs Ann. 
 Nat. Hist. 1850, 334, t. 8, fig. 11. 
 
 Amongst Cladophora fracta, in brackish ditch. 
 
 Mr. Ralfs says : " The turgid spores and large compressed heterocysts 
 characterise this species," of which we have no knowledge. 
 
 Plate XOVI. fig. 9. Portions of trichomes, with heterocysts and 
 spores X about 400. After Ilarvey. 
 
242 NBMATOGEN^. 
 
 Sphaezozyga Jacobi. Mcdfs Ann. Nat. Hist. 1850, 332, t. 8, fg. 8. 
 
 Forming thick bhiish green gelatinous masses, from which 
 the filaments issue in long rays. 
 
 Trichomes elongated, ends attenuated, joints quadrate, then 
 globose, the terminal one longer than broad, and usually conical. 
 Heterocysts spherical, larger than the joints. Spores oblong 
 or cylindrical, one or two on each side of the heterocysts. 
 
 Size. Cells about -005 mm. Spores -008 x •02--025 mm. 
 
 Berkeley in Eng. Bot. ii., t. 2,826, fig. 2. 
 
 Cylindrosporium licheniforme, Kutz. Spec. 292 ? 
 
 Jn streams, pools, &c. 
 
 We have seen no specimen of this, and cannot say whether it is 
 Agardh's species or not. Although ignored by Continental botanists, it 
 would seem from the figure, which we have reproduced, to be a distinot 
 species. 
 
 Plate XCiy. fig. 5. Portions of trichomes with heterocysts and 
 spores X about 400, after Ralfs. 
 
 Sphaerozyga Bloozeana. Salfs Ann. Nat. Hist. 1850, t. 8, f. 12. 
 
 Trichomes scattered, joints minute, somewhat orbicular. 
 Heterocysts minute, barrel-shaped, much narrower than the 
 spores. Spores very turgid, often nearly orbicular or broadly 
 elliptical, much larger than the joints or heterocysts. 
 
 Size. Cells about •0035--004: mm. Spores about -008 X 
 •012--015 mm. 
 
 Mixed with other algae. 
 
 " I have only seen imperfect and dried filaments of this species inter- 
 mixed with Nostoc va/riegatum, Moore ; in a recent state therefore the 
 form of the joints may not agree with the above description, still the 
 large turgid spores must distinguish it from every species but S. 
 Berlceleyana, and from that it differs in its heterocysts, which are com- 
 paratively much smaller and also longer than broad." — Ralfs. 
 
 Plate XQW. fig. 6. Portion of trichome with heterooyst and spores 
 X about 4flO after Ealfs. 
 
 Sphszozyga leptospezma. Rcdfs. Ann, Nat. Hist. 1850, 334, t. 8, 
 
 /. 13. 
 
 Forming large shapeless gelatinous masses, varying from deep 
 green to pale yellowish green. 
 
 Trichomes elongated, not constricted at the dissepiments, 
 joints longer than broad, separated only by transverse dissepi- 
 ments, which are not contracted, and indeed are often so obscure 
 that they can hardly be detected. Heterocysts at first ban-el- 
 shaped, finally elliptic, broad at the spores. 'Spores cylindrical, 
 4-6 times longer than broad truncate, slightly broader than the 
 ordinary joints. 
 
NOSTOCBJE. 243 
 
 Size. Cells -004 mm. diam. Spores about -007 x •02--03 
 mm. 
 
 Gylindrospermiim leptospermum, Kutz. Tab. Pbyc. i., t. 99. 
 f. 11. Bot. Leit. p. 198. 
 
 In ditches and pools. 
 
 " The confluent vegetative cells, with their obaoure dissepiments, dia- 
 tingniah this from every other British speoiea." — Ralfs. 
 Of this also we have no personal knowledge. 
 
 Plate XCIV. fig. 8. Portion of triohome with heterooyst and spores 
 X aboQt 400. After Ealfs. 
 
 Sphserozyga eUstica. Malfs Ann. Nat. Hist. 1850, 333, t. 8,Jig.9. 
 
 Stratum deep bluisb green, tender. 
 
 Trichomes elongated, constricted at the dissepiments, joints 
 about equal in length and breadth, but when dividing they 
 lengthen, and though quadrate in the recent plant they acquire 
 slightly rounded angles when dry. Heterocysts at first barrel- 
 shaped, then elliptic. Spores cylindrical, 4-8 times longer 
 than broad, ends at first truncate, but rounded after separation. 
 
 Size. Cells about '005 mm. Spores '008 X "025 mm. 
 
 Sphcerozyga elastica, Agardh Icon. Alg. ? 
 
 Cylindrospermum elongatum, Kutz. Tab. Phyc. i., t. 99, f. 
 111. 
 
 In bogs. 
 
 " The moniliform filaments and shorter jointa distinguish this species 
 from S. leptosperma, and its elliptic heterocyats from S. Jacoii and iS. 
 Carmichaeli." — Ealfs . 
 
 Plate XCIV. fig. 7. Portions of trichomes with heterooysta and 
 spores X about 400, after Ealfs. 
 
 Genus 98. CYLINDROSPERiaUin. {Kutz) Balfs 1860. 
 
 Heterocysts terminal, single. Other characters the same as 
 in Sphcerozyga, Spores originating in cells placed just below 
 the heterocysts. 
 
 Cylindirospezmum maczoBpezmum. Kvtz. Tab. Phyc. i., t. 98, 
 
 f. i. 
 
 Trichomes curved or nearly straight, pale blue green, more 
 or less interwoven ; joints globose or elliptic, often mixed with 
 others somewhat cylindrical, either homogenous or granular. 
 Heterocysts terminal, elliptical. Spores elliptic oblong, or 
 oblong cylindrical, green or yellowish brown, darker brown 
 when mature, granular, twice as long as broad. 
 
 2 M 
 
244 NKMATOGEN^. 
 
 Size. Cells ■003--004 mm., heterocysts rather longer. 
 Spores -014 X -OSS'-OS mm. 
 
 Kirch. Alg. Sehl. 237. Eahh. Alg. Enr. ii., 186. 
 Anabaina impalpebralis, Hass. Alg. 283, t. 75, f. 3. 
 
 In ditches and ponds. 
 
 Plate XCV. fig. 1. Trioliomes with heteroeyats and spores X 400. 
 
 Cylindrospexmam cateaatum. Rcdfs Ann. Nat. Hist. t. 8,/. 14. 
 
 Stratum bluish green. Trichomes very fine elongated 
 straight, or slightly flexuous, generally parallel, monilifoTm. 
 Joints sphserical minute. Heterocysts oval. Spores 2-8 in 
 each series, at first sphaerical, then more or less oval, but little 
 broader than the heterocysts. 
 
 Size. Cells about -003 mm., heterocysts a little longer, 
 spores about -006 x "008 mm. 
 
 Eabh. Alg. Exs. No. 1358. 
 
 In fresh water. 
 
 Clearly distinguished from the preceding species by its nu- 
 merous spores. 
 
 Plate XCV. Jiff. 2. Trichomes with heterocysts and spores X 400. 
 
 GEJfus 99. NODULA&IA. Mertms. (1822.) 
 
 Trichomes distinctly vaginate, with very closely compressed 
 disc-shaped joints, collected in a gelatinous or membranaceous 
 irregularly diffused stratum. Heterocysts intercalated at re- 
 gular intervals, vegetative joints nearly equal, transversely 
 compressed. Spores fuscous, or golden yellow, becoming tawny, 
 globose, slightly compressed. 
 
 Nodnlaxia litoiea. (TAw.) Thur. Ann. Sci. Nat. 1875, 378. 
 
 Scarcely gelatinous, forming a deep green fleecy covering to 
 floating plants on which it occurs. Trichomes of considerable 
 diameter, nearly straight. Joints of a beautiful blue green 
 colour, very short and compressed, giving the filaments the ap- 
 pearance of an Oscillaria. Heterocysts pale reddish. Spores 
 elliptical, at length acquiring a deep brown colour. 
 
 Size. Trichome, without sheath, -012 mm. 
 
 Born, and Thur. Notes Algol, ii., 121, t. 29, f. 1-9. 
 
 Spermosira litorea, Kutz. Phy. Gen. 213. Babh. Alg. Eur. 
 ii., 186. Harv. Phy. Britt. t. 113, f. c. 
 
 In muddy, brackish ditches. 
 
NosTooEji:, 245 
 
 Plate XOV. fig. 3. a, portion of triohome, with heterooysts X 400 ; 
 b, portion X 600 ; c, fertile portion, with spores X 600 ; d, spores X 600 ; 
 
 e, spore germinating, after Thuret. 
 
 Nodulaxia Kaxveyana,. Thur. in Ann. Sci. Nat. 1875, 378. 
 
 Trichomes much curTed, composed of cells nearly as long as 
 broad. Heterocysts subquadrate, rather longer than wide, and 
 of the same width as the joints. Spores sphserical, almost 
 twice the diameter of the joints. 
 
 Size. Trichomes "0065 mm. diam. y 
 
 Born, and Thur. Notes Alg. ii., t. 29, f. 14-16. y 
 Spermosira Harveyana, Thw. in Harv. Phyc. Britt. t. 173, 
 
 f. c. Rabh. Alg. Eur. ii., 295. 
 
 In brackish ditches. 
 
 Plate XOV. fig. 4. as, portion of triohome with heterooysts x 400 ; i, 
 the same X 600 ; e, portion of triohome with spores X 600 ; d, germi- 
 nating spores, after Thnret. 
 
 Pamilt II. LYNGBY^. 
 
 Filaments without heterocysts, and destitute of a terminal 
 hyaline hair, single, and scattered, or numbers associated in 
 bundles and enclosed in a common sheath, often radiating. 
 Joints shortly cylindrical, disc-shaped in section. 
 
 Genus 100. SFIRULINA. Link. (1834.) 
 
 Trichomes articulated, spirally twisted, motile, nestling in a 
 more or less liquid colourless matrical mucilage. Propagation 
 unknown. 
 
 Consult Cohn in Nova Acta Car. leop. vol. xxiii. Braun in Botanische 
 Zeitung 1852, p. 396. Keinicke Beitr. zur neuern Mikrosk ii., pp. 
 1-56. 
 
 Spizulina Jemnexi. K%U. Tah. Phyc. i., t. 37, /. 11. 
 
 Trichomes more or less elongated, distinctly articulated, 
 spirals lax, distant, joints equal in length to their diameter, or 
 a little shorter. Cell-contents pale or bright blue green. 
 
 Size. Trichomes -OOT-'OOS mm. diam. 
 
 Eabh. Alg.Eur. i., 90. Kirch. Alg. Schl. 250. 
 
 Spirillum Jenneri, Hass. Alg. 277, t. 75, f. 5. 
 
 Arthrospira Jenneri, Hedwigia i., p. 32, t. 5. 
 
 In stagnant water. 
 FUte XCVI. fig. 1. Portions of trichomes X 400, 
 
246 NEMATOGENJi. 
 
 Spimlina oscillaxioides. Tiirp, 
 
 Solitary, or forming little green tufts, sometimes almost 
 radiating. Trichomes more or less elongated, nearly erect, pale 
 blue green, twisted in lax or dense spirals, endowed with active 
 motion. 
 
 Size. — Trichomes •0015-'002 mm. diam. 
 
 Kutz. Tab. Phyc. i., t. 37, f. 8. Eabh. Alg. Eur. ii., 91. 
 Kirch. Alg. Schl. p. 250. Cohn Nova Acta xxiv., t. 15, f. 
 15. 
 
 var. b. minutissima. Sabh. Alg. Mir. ii., 91. 
 
 Trichomes abbreviated, more loosely spiral. 
 Spirillum minutissimum, Hass. Alg. 278, t. 75, f^ 8. 
 Spimlina hrevis, Kutz. Tab. Phyc. i., t. 37, f. 9. 
 
 In fresh, brackish, or thermal waters. 
 
 Plate XCVI. fig. 3. Portions of trichomes X 400. Fragment 
 further magnified. 
 
 SpinUiiia tenuissima. Kutz. Spec. Alg. 236. 
 
 Forming a membranaceous, lubricous, dark blue green floating 
 stratum, trichomes very thin, flexuous, very densely spiral, en- 
 dowed with active motion ; joints very indistinct. 
 
 Size. — Trichomes very thin. Spirals '005 mm. diam. 
 
 Eabh. Alg. Eur. ii., 92. Harv. Phyc. Britt. t. 105, f. c. 
 
 In brackish ditches. 
 
 Floating in large blue green masses on the surface of brackish ditches. 
 The threads are too delicate for measurement, and appear only as lines 
 under a magnifying power of 400 diameters. 
 
 Plate XOFI. fig. 2. Portions of trichomes X 400. 
 
 Genus 101. OSCILLARIA. Base. (1800.) 
 
 Trichomes simple, usually distinctly articulate, rigid, straight, 
 or a little curved, rarely circinate or spirally convolute, for the 
 most part brightly coloured (blue-green, steel-blue, violet, 
 oeruginous, &c.), motile, nestling in a matrical mucilage; joints 
 disc-shaped in the front view, without a sheath distinct from 
 the trichome. 
 
 Consult Dr. d'Alquen in Quart. Journ. Mior. Sci. iv. (1856), p. 245. 
 
 The species are at present distinguished by very artificial characters, 
 whigh are by no means permanent, in which respect the genus is not in a 
 much better condition than it was forty years ago. 
 
LYNGBV^. 247 
 
 Oscillaria tenexzima. Kvt^. Tab. Phyc. i., t. 38, /. 8. 
 
 Solitary and scattered, or associated in fascicles. Trichomas 
 straight, indistinctly articulate, joints equal in length to their 
 diameter, or a little longer or shorter, ends somewhat acute, 
 slightly inclined ; cell-contents pale blue green, or oliye, homo- 
 genous or Tery finely granular. 
 
 Size. Threads •0018--0025 mm. diam. 
 
 Eabh. Alg. Eur. ii., 96. 
 
 In ditches, amongst decaying vegetable matter, 
 Plate XCVI. fig. i. Trichomea X 400. 
 
 Oscillazia leptotzicha. Xutz. Tab. Phyc. i., t. 38, /. 9. 
 
 Solitary, scattered, or collected in a very thin blue green 
 stratum, trichomes very slender, slightly curved, indistinctly 
 articulate, joints twice as long as broad, or after division equal, 
 very minutely punctate at the periphery, attenuated at the ends, 
 which are straight, curved, or deflexed, cell-contents pale blue, 
 green, homogenous or finely granular. 
 
 Size. Threads -003 mm. diam. 
 
 Eabh. Alg. Eur. ii., 97. 
 
 In fresh or brackish ditches. 
 Plate XCFI. fig. 5. Triohomes X 400. 
 
 var. splendida. CGrev. Fl. Edin. 3040 
 
 Size. Trichomes not exceeding -002 mm. diam. 
 Oscillatoria splendida, Eng. Fl. v., 375. Harv. Man. 164. 
 Hass. Alg. 251, t. 72, f. 8. 
 
 In tubs of water in a stove. Edinburgh Botanic Gardens. 
 
 Plate XCFI. fig. 6. Trichomes X 400. 
 
 Oscillazia spizalis. Vai'm,. Harv. Phyc, Britt. t. IOSb. 
 
 Efifused in a firm coriaceous glossy black stratum. Trichomes 
 radiating, slender, long, flexuous, regularly twisted in spirals. 
 Size. Threads •0035--004 mm. diam. 
 Spirillum rupestre, Hass. A]g. 277, t. 75, f. 6. 
 Spirulina i-upestre, Eabh. Alg. Eur. ii., 93. 
 
 On rocks by the seaside. 
 
 " It spreads over the dry naked earth. Stratum eeveral feet in extent, 
 firm, coriaceoua, of a glossy black colour, void of lubricity. Filaments 
 about half a line in length, twisted like a corkscrew, radiating in all di- 
 reotions." — C 
 
 Plate XCVIII. Jig- 7. Trichomes X 400, from the original specimens. 
 
248 NEMATOGEN^. 
 
 Oscillaria rubiginosa. Cmynichael Alg. App. ined. 
 
 Stratum gelatinous, dark purple; trichomes very thin, straight, 
 indistinctly articulated, laid on a thin, compact, greenish sub- 
 stratum. 
 
 Size. Threads •004--0045 mm. diam. 
 
 Oscillaria violacea, Rabh. Alg. Eur. ii., 113. Eng. Fl. v. 
 377. 
 
 OseilJatona violacea, Hass. Alg. 254, t. 72, f. 10. Harv. 
 Man. 166. Johnst. Fl. Berw. ii., 264. 
 
 Conferva mucosa confragosa rivulis innascens, Dillen (?) 
 
 Rapid streams, and on stones at the bottom of rivers. 
 
 When dry the filaments of this species assume a blackish green oast, 
 with an evident gloss. Striae when dried almost invisible, at a distance 
 of about two diameters from each other. — JSassall, 
 
 As another species is called Oscillaria violacea (Wallr), which has 
 priority, the name proposed by Garmiohael must be adopted. 
 
 Plate XCFIIl. fig. 6. Portions of trichomes X 400, from the original 
 specimens. 
 
 Oscillaria subfnsca. Vauch. Conf. 193, t. 15, f. 5. 
 
 Forming a very thin, greenish brown, then blackish stratum, 
 shortly radiating. Trichomes equal, straight, curved at the 
 apex (curvature of 4 to 6 joints), joints about equal in length to 
 their breadth (after division shorter), dissepiments very dis- 
 tinctly granulate, extreme apical point fimbriate, or bearded. 
 Cell-contents pale greenish steel-blue, granular. 
 
 Size. Threads •0045--006 mm. diam. 
 
 Rabh. Alg. Eur. i., 100. Kirch. Alg. Schl. p. 246. Mack. 
 Hib. p. 240. Eng. Fl. v., 377. Harv. Man. 166. 
 
 Oscillatoria suhfusca, Hass. Alg. 253, t. 72, f. 9. 
 
 Attached to wood, rocks, stones, &c,, in streams. 
 
 "Stratum extensive, soft, slimy, void of tenacity, wrinkled, of a 
 dnsky grey colour, when dry greyish-brown, streaked with green to- 
 wards the edges ; filaments very slender, strise invisible." — Ha/rvey. 
 
 Tlate XCVI. fig. 7. Portions of trichomes X 400. 
 
 Oscillaria serugescens. Drvmm. Ann. Nat. Eist. (1838) i,p. 1. 
 
 Stratum of a fine deep green, highly gelatinous, when dried 
 Eeruginous blue, and glossy ; trichomes very slender, opaque 
 green, conglomerated in large masses, rarely floating, or broken 
 into fragments and suspended like cloudy flocculi in the water, 
 joints about half their diameter long. 
 
 Size. Trichomes -005 mm. diam. 
 
 Oscillatoria cervgescens, Hass. Alg. 249, t. 72, f. 2. Harv. 
 Man. 163. 
 
LYNGBY^. 249 
 
 In lakes and pools. 
 
 This is the species which Dr. Drummond described as the "colouring 
 substance of Glasslough Lake, Ireland." He commences by stating that 
 " Glas-lough " signifies " green lake," an appellation given to it from 
 time immemorial on account of the hue of its waters, which exhibit a 
 green tinge, equal to, or exceeding in intensity, that of the sea, though 
 itis not at all times equally striking. " From the accounts I received, 
 the green colour is evident in the lough throughout the year, and if I 
 may judge from my own observations, every drop of it is impregnated 
 with the oscillatory filaments." " When a little of the water is lifted in 
 the hand it seems perfectly transparent, and it appears equally clear at 
 the edges of the lake, but at a depth of two feet the bottom is indis- 
 tinguishable, and the water presents a sort of feculent opacity, accom- 
 panied by a dull, dirty, greenish hue. On lifting some of this in a glass 
 it seems at first sight quite transparent, but on holding it up to the light 
 innumerable minute flocouli are seen floating through every part of it, 
 and producing a mottled cloudiness throughout the whole." "At first I 
 could only find the plant diffused through the water, but at length I dis- 
 covered a wet ditch extending from the lake into an adjoining field, and 
 there it appeared swimming on the surface in large masses several inches 
 in thickness, and above a foot and a half in length. These seemed evi. 
 dently to be produced by an agglomeration of the filaments floated in 
 from the lake, matted together at the surface, and increased in growth. 
 The surface of these masses, where dried by the contact of the air, was 
 of a bright bluish verdigris hue, while the parts immersed in the water 
 were of a dull opaque green. 
 
 "On examining specimens in the microscope, I sometimes observed 
 their motions to be very vivid, and in other instances little or no motion 
 could be perceived. They are extremely minute, their transverse striae 
 very numerous, and at distances of about half a diameter from each 
 other. The filaments in the conglomerated masses appeared to me to be 
 many inches long, and running parallel together ; the broken fragments 
 dispersed through the lake cross each other in all directions." 
 
 Plate XCVUI. fig, 5. Triohomes from specimen collected by Drum- 
 mond X 400 diam. 
 
 Oscillaria tenuis. Ag. Syst. Alg. p. 60. 
 
 Forming a bright green, or dark blue green stratum, shortly, 
 or elongated radiating. Triohomes straight, rather rigid, more 
 or less endowed with active motion ; joints equal or half as 
 long as broad, sometimes a little constricted at the dissepi- 
 ments, which are delicately granulated ; apex more or less 
 attenuated, obtuse, curved or straight ; cell-contents pale 
 watery blue. 
 
 Size. Threads •054:--006 mm. diam. 
 
 Eabh. Alg. Eur. i., 102. 
 
 Oscillatoria limosa. Hook Fl. Scot, ii., 79. 
 
 Oscillaria viridis, Kutz. Tab. Phyc. i., t. 41, f. 6, Eng. Bot. 
 t. 2523. Johnst. Fl. Berw. ii., 264. 
 
 Oscillatoria contexta, Carm. Hass. Alg. 256, t. 71, f. 7, 4, 
 6. Eng. Fl. T., 376. Harv. Man. 165. 
 
 Oscillatoria tenuis, Hass. Alg. 248, t. 72, f. 1. (?) Jenn. 
 Tunb. Wells 188. Harv. Man. 163. Grey. Fl. Edin. 303. 
 
250 HEMATOGBN^. 
 
 Mack. Hib. 239. Gray. Arr. i., 281. Eng. Fl. v., 374. Eng. 
 Bot. ii., 2525. 
 
 In ditches, swamps, inundated places, now and then free 
 swimming ; throughoat the year. 
 
 Very variable, passing into several moderately distinct varieties, of 
 which the bright green one called viridis is the most beantif ol, and by 
 no means rare. 
 
 The form which Carmichael called OsciUatoria contexta has thus been 
 described by \\\m : — " Stratum of indeiinite extent three feet and up- 
 wards, exceedingly thin, and peeling off in large flakes in dry weather, 
 of a deep but shining black colour, scored or striated in all directions. 
 These strise are caused by thick fasciculi of filaments, shooting out 
 either parallel to or across each other, changing their course from time 
 to time and sending o£E lateral fasciculi. The filaments are rather thick 
 about a line in length, straight, or variously curved, of a greyish green 
 colour, and they radiate with great rapidity. A portion of the stratum, 
 not more than a line in diameter, placed in a watch-glass filled with 
 water, overspread the whole area of the glass -with filaments in the 
 course of a night." Hassall says of it, " the filaments are in calibre not 
 less than those of O. tenuis, from which species it is distinguished 
 chiefly by its colour." 
 
 Plate XOVI. fig. 8. Portions of trichomes X 400. Plate XOTTI, 
 Jig. 1. Portions of trichomes of the variety viridis X 400. 
 
 Oscillazia antliaria. Jwgens Alg. Exs. iVb. 14. 
 
 Expanded in a gelatinous, sometimes very broad submem- 
 branaceous stratum, dark steel-blue. Trichomes rigid, straight, 
 sometimes tranquil, sometimes oscUlating, curved at the attenu- 
 ated apex (curvature of 3 to 4 joints) ; joints equal, or nearly 
 equaljin length and breadth (after division half as long), dissepi- 
 ments distinctly granular, extreme apex obtusely rounded. Cell- 
 contents pale steel-blue, or blue green, nearly homogenous. 
 
 Size. Threads •0045-"0055 mm. diam. 
 
 Kutz. Tab. Phyc. i., t. 40, f. 6. Rabh. Alg. Eur. ii., 100. 
 
 Oscillaria parietina, Vauch. Conf., t. 15, f. 8. 
 
 Around pumps, cisterns, &c. 
 plate XCVll- fig- 2. Portions of trichomes x 400. 
 Oscillaria muscoram. Carm. MSS. 
 
 Stratum 3-4 inches, of a dait bluish-green colour, slightly 
 luhricous, shortly radiating, creeping over mosses. Trichomes 
 variously curved, pale blue green, joints about equal in length 
 to their diameter. 
 
 Size. Trichomes •006--007 mm. diam. 
 
 Hook. Eng. Fl. v., 365. Harv. Man. 164. Hass. Alg. 
 252, t. 72, f. 12. 
 
 In rapid streams, on Hypnum ruscifolium, &c. 
 
 " Stratum 3 or 4 inches in extent, closely interwoven with the branches 
 and leaves of mosses, of a bluish green colour, and slightly lubricous 
 
LYNGBY^. 251 
 
 Filaments a line or two in length, variously curved and radiating ; 
 striae at. the distance of a diameter from each other." — Carmichael. 
 
 Plate XCYIIl. jig. 8. Portions of trichomes X 400, from the 
 original specimens. 
 
 Oscillaxia subuliforinis, Thw. in Earv. Phyc. Britt. 
 
 Stratum of an intense seruginous green. Trichomes bright 
 green, subuliform, gradually attenuated towards the apices, which 
 are subacute and much curved ; joints about three-fourths as 
 long as broad, homogenous. 
 
 Size. Trichomes -OOe-OO? mm. diam. 
 
 Harv. Phyc. Britt. t. 251 b. Eabh. Alg. Eur. ii., 292. 
 
 In brackish ditches. Summer and autumn. 
 Very bright emerald green, and certainly an attractive species. 
 
 Plate XCVIII. fig. 3. Trichomes from original specimen X iOO 
 diam. 
 
 Oscillazia limosa. Ag. Syst. Alg. 66. 
 
 Trichomes rigid, straight, actively oscillating, blue-green, 
 interwoven in a thin mucilaginous radiating green stratum, 
 distinctly articulate, joints nearly equal or a little longer than 
 broad (shorter after division, often half as long as the dia- 
 meter), dissepiments granulated, apex obtuse, straight or 
 cux'ved ; cell-contents pallid, homogenous or slightly granular. 
 
 Size. Threads 'OOS-'Ol mm. diam. 
 
 Eabh. Alg. Eur. i., 104. Hook. Br. Fl. ii., 374. 
 
 Conferva limosa, PL Dan. t. 1549. 
 
 Oscillatoria limosa, Hass. Alg. 246, t. 71, f. 2. (?) Eng. Fl. 
 v., 374. Gray. Arr. i., 280. Eng. Bot. ii., 186. Harv. Man. 
 162. Johnst. Fl. Berw. ii., 265. Mack. Hib. 239. Fl. Dev. 
 ii., 56. 
 
 Oscillaria tenuis d. limosa, Kirch. Alg. Schles. p. 247. 
 
 There are several varieties, differing chiefly in colour, of which Raben- 
 horst enumerates ten. 
 
 If Hassan's figure is magnified in proportion to the res!;, then his t. 71, 
 f . 2, can scarcely be the present species, for its diameter would be equal 
 to that of 0. FroUchii, whereas this scarcely ezceeds half that thickness. 
 All the figures of Oscillaria given in Hassall's work are acknowledged to 
 be very defective. 
 
 Plate XCVII. fig. d. Portions of trichomes X 400. Fig. 4, portions 
 of trichomes of the variety chalyhea X 400. 
 
 Oscillaria izzigua. Kvtz. P\yc. Oen. 189. 
 
 - Stratum thin, expanded, compact, dark steel-blue, by oblique 
 light purplish violet ; trichomes straight, flexile, pallid then 
 livid steel blue, a little attenuated at the apex, joints equal in 
 length to their diameter (after division half as long) dissepi- 
 
 2 N 
 
252 
 
 NEMATOGBN^. 
 
 ments beautifully granulated, extreme apex broadly rounded, or 
 somewhat beaked, cell-contents homogenous or delicately 
 granular. 
 
 Size. Threads •0076--01 mm. 
 
 Kutz. Tab. Phyc. i., t. 42, f. 4. Eabh. Alg. Eur. ii., 107. 
 
 On wet rocks, walls, or overrunning mosses. 
 
 The variety " subsalsa," bearded at the apex, was found on Greenwich 
 Pier in 1861. 
 
 Plate XCFII. fig 5. Portions of triohomes X 400. 
 
 Oscillazia nigza. Va^u:h. Qonf. 192, t. 15,/. 4. 
 
 Stratum more or less compact, somewhat membranaceous, 
 often floating, steel-blue, or dark olive nearly black, with radii 
 more or less elongated, of the same colour. Trichomes straight 
 or slightly flexuous, obtusely rounded at the apex, or attenuated, 
 and sometimes bearded ; joints equal in length to their diameter 
 (after division one half or one third as long) ; dissepiments very 
 distinctly granulated, apiculus often straight, somewhat rostel- 
 late and bearded, rarely slightly curved ; cell-contents pale olive , 
 finely granular. 
 
 Size. Threads 'OOO-'Ol mm. diam. 
 
 Rabh. Alg. Eur. i., 107. Kirch. Alg. Schl. 247. Hanr. 
 Man. 165. Eng. Fl. v., 376. Eng. Bot. t. 2527. 
 
 Oscillatoria nigra, Hass. Alg. 255, t. 71, f. 3. Hook. Fl. 
 Scot. 79. Jenn. Tunb. Wells 188. Mack. Hib. 239. Gray 
 Arr. i., 281. 
 
 Conferva fontinalis, Dillw. Conf. t. 64. Huds. Fl. Ang. 
 592. Lightf. Fl. Scot. 976. With. Arr. iv., I;i8. 
 
 In ditches and ponds. 
 
 " Stratum extensive, blackish, with a shade of green, when dry bine- 
 black, very rapid in its growth, and sending ont long, vividly oscillating 
 rays." — Harvey. 
 
 Plate XOYII.fig. 6. Portions of trichomes X 400. 
 
 Oscillazia nigzo-vizidis. Tkwaites in Sarv. Phyc. 
 
 Stratum thin, of a dark olive green, almost black, growing 
 upon the mud, and subsequently floating in large masses. 
 Trichomes pale dull green, with obtuse, distinctly curved, 
 scarcely attenuated apices ; joints indistinct, about half as long 
 as broad, cell-contents slightly granulose. 
 
 Size. Trichomes •012 mm. diam. 
 
 Harv. Phyc. Britt. t. 251 a. Eabh. Alg. Eur. ii.. 292. 
 
 In brackish ditches. August. 
 Plate XC7II1. fig. 2. Trichomes of O. nigro-mridis X 400 diam. 
 
LYNGBY^. 
 
 253 
 
 Oscillaiia chalybea. Mertens, in Jv/rgem Alga. 
 
 Floating. Stratum broadly expanded, with, long radii, dark 
 blue green or steel-blue, shining ; trichomes pale steel-blue, 
 slightly flexuous, a little attenuated at the apex, joints three or 
 four times shorter than their diameter, a little contracted at the 
 dissepiments, which are not granulated, apiculus slightly curved, 
 obtusely rounded, now and then rostellate, cell-contents pale 
 steel-blue, granular. 
 
 Size. Threads -OOSS-'Ol mm. diam. 
 
 Kutz. Tab. Phyc. i., t. 40, f. 8. Rabh. Alg. Eur. ii., 108. 
 
 In still and stagnant water. 
 
 The specimens figured were collected from ataiik in one of the stoves 
 of the Royal Botanic Gardens, Regent's Park. 
 
 Flate XOVIII. fig. 1. Trichomes of O. ohaVybea X 4O0 diam. 
 
 Oscillazia Fzolichii. Kutz. Phyc, Qen, 189. 
 
 Stratum dark steel-blue, or at first olive, then dark blue, 
 often elongated, radiating, opaque, shining ; trichomes nearly 
 equal, straight ; joints 2, 3, or 4 times shorter than their 
 diameter, with a double series of granular points more or less 
 dense at the junction, often confluent, so as to resemble a single 
 series ; apiculus broadly rounded, straight, or declined ; cell- 
 contents blue, becoming steel-blue, homogenous. 
 
 Size. Threads -OIS-'OIS mm. diam. 
 
 Kutz. Tab. Phyc. i., t. 43, f. 1. Rabh. Alg. Eur. ii., 109, 
 
 Osdllatoria mucosa, Hass. Alg. 247, t. 71, f. 1. 
 
 In ditches, pools, and boggy places, sometimes amongst 
 mosses. 
 
 The finest of the species yet detected in Britain. 
 
 Plate XCVII. f. 7. Portions of trichomes x 400. 
 
 Oscillazia insignis. Thwaites in phyc. Britt. 
 
 Stratum thin, covering decayed vegetable matter at the 
 bottom of a ditch, with a dark-brown coating, becoming some- 
 what greenish in drying ; trichomes very large, rather brittle, 
 their apices rounded, somewhat oblique, and furnished with 
 numerous motionless cilia : cell-contents distinctly granulose. 
 
 Size. Trichomes '018 mm. with sheath. 
 
 Rabh. Alg. Eur. ii., 293. Harv. Phyc. Brit, ii., t. 251, f. c. 
 
 In a brackish ditch. November. 
 
 A portion of the trichome from the original specimen has been 
 figured, but Professor Harvey was evidently of opinion that it was a 
 strictly marine species. There seems at least to be no doubt that it is 
 
254 NEMATOGEN^. 
 
 in reality a Lynghya, allied to L. cestuariij and not a true Osdllaria. 
 We are indebted to Professor Percival Wright for an examination of 
 anthentic specimens of this, and several other of Harvey's species. 
 
 Plate XCVllI. jig. 4. Portion of trichome X 400. 
 
 Douhiful Species. 
 Oscillaxia Dickiei (Sass.) Rabh. Alg. Eiir. ii., 113. 
 
 Stratum pale chesnut-brown, gelatinous, shining ; trichomes 
 of medium size, long, straight, fragile, with visible spaces 
 between the joints. 
 
 Size. Not determined. 
 
 Oscillatoria Dickiei, Hass. Alg. 258, t. 72, f. 13. 
 
 Pools of fresh water near the sea. 
 
 The colour of this species is so pecnliar as at once to distingnish it 
 from all others ivhich have been described. This colour is preserved in 
 drying; the filaments are of nearly the same diameter with those of 
 O. tenuis, but they preserve their c^bre when dried. — Bassall. 
 
 Oscillaxia thexmalis. {Bass.") Raih. Alg. Eur. il., 113. 
 
 Trichomes straight, rigid, fragile, green ; divisions of the 
 joints distinct, rather remote. 
 Size. Not determined. 
 Oscillatoria thennalis, Hass. Alg. 250, t. 72, f. 3. 
 
 In warm water. 
 
 The figures and descriptions in Hassall's work are wholly insufficient 
 for the proper identification of this and the following species. 
 
 Oscillaxia vixescens (Ha«s.) Rabh. Alg. Eur. ii., 113. 
 
 Stratum pale blue-green ; trichomes of medium size, pale 
 yellowish-green, with the joints rather distant, nearly equal in 
 length to their diameter. 
 
 Size. Not determined. 
 
 Oscillatoria virescens, Hass. Alg. .250, t. 71, f. 9. 
 
 On the ground. 
 
 Genus 102. MICROCOLEUS. Desm. (1823.) 
 
 Trichomes rigid, articulate, crowded together in bundles, 
 enclosed in a common mucous sheath, either closed or open at 
 the apex ; sheath ample, colourless, more or less lamellose, 
 rarely indistinct. = Chthonoblastus, Kutz. (1843.) 
 
LYNGBYiE. 255 
 
 " Triohomes enclosed in a transparent sheath from which they emerge to 
 reproduce new filaments, sheath containing several triohomes. Fila- 
 ments growing in scattered creeping erect or floating wick-like bundles." — 
 Thl(ret. 
 
 Sydrocole-wm thermale Kutz., mentioned in Quart. Journ. Micr. Sci. 
 (1867) p. 86, as having occurred in Ireland, we have never seen, and, 
 therefore, do not know whether it should be included in Miorocoleus. 
 
 Micxocoleus gracilis. Hass. Alg. 261, t. 70, /. 2. 
 
 Effused broadly in a thin dark green stratum. Triohomes 
 pale blue green, slightly curved, in fascicles densely contorted 
 about the apex, joints 2-3 times longer than their diameter, 
 either continuous or distinctly separated, granulated, divisions 
 paler, nearly hyaline, a little contracted about the apex, extreme 
 apiculus conical, now and then slightly curved, special sheath 
 narrow, very delicate, universal sheath very thick lamellose. 
 
 Size. Triohomes •0025--003 mm. ; fascicles ■09-"12 mm. 
 
 Kirch. Alg. Schl. 244. 
 
 Miorocoleus marinus, Harv. Man. 168. 
 
 Chthonoblastus salinus, Kutz. Tab. Phyc. i., t. 58, f. 2. Rabh. 
 Alg. Eur. i., 133. 
 
 Oscillatoria chtJionoplastes, var. a. Bng. Fl. v., 373. Eng, 
 Bot. ii., t. 2523. Mack. Hib. 239. 
 
 On salt marshes. 
 
 "Fronds fixed at the base, floating freely in the water, an inch long, 
 tufted, dichotomously branched, branches slender capillary widening up- 
 wards, with club-shaped tips ; colour olivaceous green or yellowish. 
 When ruptured the branches jiischarge innumerable needle-shaped fila- 
 ments, which, when the plant is growing, radiate and oscillate from the 
 tips of the branches." — JJarvey. 
 
 Plate XCIX. fig. 1. End of fascicle of trichomes with sheath x 400. 
 
 Miczocoleus chthonoplastes. Thur. in Ann. Sci. Nat. (1875) 
 
 p. 377. 
 
 Stratum thin, or thicker and rather compact, dingy seru- 
 ginous green ; trichomes slightly flexuous, equal, twisted, in 
 dense fascicles, joints nearly twice as long as their diameter, 
 rather remote from each other, leaving a hyaline space between 
 them, apiculus attenuated, rather elongated ; special sheath 
 very delicate, universal sheath narrow, scarcely lamellose. 
 
 Size. Trichomes •0035-'004 mm. ; fascicles •03--035 mm. 
 
 Chthonoblastus Lynghyei, Kutz. Tab. Phyc. i., t. 58, f. 1. 
 
 Miorocoleus anguiformis, Hass. Alg. 261, t. 70, f. 1. Kirch. 
 Alg. Scbl. 244. 
 
 Chthonoblastus anguifoiinis, Kutz. Tab. Phyc. i., t. 57. Rabh. 
 Alg. Eur. ii., 133. Harv. Phyc, Britt. t. 249. 
 
 On the naked ground, by roadsides, &c. 
 
 Plate C. fig. 1. Fascicle of trichomes with sheath X 400. 
 
256 NBMATOGEN^. 
 
 Microcolens terzestxis. Desm. PI. Crypt. Exs. i., No. 55. 
 
 Stratum more or less expanded, deep blue green or steel blue, 
 or olive, becoming brownisb, membranaceous, mucilaginous ; 
 tricbomes equal, collected in filiform fascicles, sometimes mucb 
 elongated, extruding from the opening of a common sheath in a 
 penicillate manner, joints equal in breadth and length, dissepi- 
 ments granulated, apiculus acute, straight. 
 
 Size. Trichomes •005--006 mm. ; fascicles -OTo-OS mm. 
 
 Kirch. Alg. Schl. p. 244. 
 
 Chihonohlaslus repens, Kutz. Tab. Phyc. i., t. 54. Eabh. Alg. 
 Eur. ii., 132. 
 
 Microcoleus repens, Hass. Alg. 260, t. 70, f. 3. Jeuner Tunb. 
 Wells 188. Harv. Man. 168. 
 
 Conferva vaginata, Eng. Bot. i., t. 1995. 
 
 Oscillaioria chthonoplastes, var. /5. Eng. Fl. v., 373. Mack. 
 Hib. 239. 
 
 Vaginaria vulgaris, Gray. Arr. i., 280. 
 
 Vaginaria chthonoplastes, Grev. Fl. Ed. 305. 
 
 On moist naked ground. 
 
 "The frond consists of numerous curled branches diverging from a 
 centre in a starry manner, and gradually tapering from a broad base ix) a 
 fine point, containing numerous deep green filaments, which radiate and 
 oscillate from the tips, and, on laceration, issue in bundles." — Harvey. 
 
 Plate XCIX. fig. 2. End of fascicle of trichomes with sheath x 400. 
 
 GEKtrs 103. INACTIS. Kvtz. (1843.) 
 
 Trichomes vaginate, indistinctly articulate, parallel and fasti- 
 giate, now and then dichotomous, very densely aggregated and 
 agglutinated in a pulvinate thallus. 
 
 " Filaments bundled, erect, growing in small rounded tufts, or in a 
 felt-like turf of indefinite extent. Trichomes very slender." — Thuret. 
 
 Inactis Czesswelli. Thur. in Ann. Sci. Nat. (1875) 377. 
 
 Forming convex roundish or oval patches, which become con- 
 fluent for several inches ; filaments hyaline, yellowish or greenish 
 olive, collected into dense rope-like branching bundles, which 
 are fastigiate ; trichomes exceedingly slender, once or twice di- 
 vided in a dichotomous manner. 
 
 Size. Trichomes -0025 mm. diam. 
 
 Schizothrix Cresswelli, Harv. Phyc. Britt. t. 160. Rabh. 
 Alg. Eur. ii., 268. 
 
 Spreading over the surface of soft sandstone rocks exposed to 
 the drip of fresh water. 
 
LYNGBY^. 257 
 
 " Mr. Cresswell states that it grows at the very top of high water mark, 
 in situations where it is exposed to the continual drip of fresh water 
 falling from high mural cliffs, and that it is most luxuriant where the 
 drip falls from the greatest height, which in the station observed is about 
 fifty feet." — Harvey. 
 
 Plate C. Jig. 2. a,, portion of fascicles of trichomes X 100 ; b, tri- 
 chomes X 400. 
 
 Inactis tinctoxia. Thur. Arm. Soi. Nat. (1875) 377. 
 
 Fasciculate csespitose, dingy brown becoming olive ; trichomes 
 single or many associated in one steath, joints eqnal in length 
 to their diameter or a little longer ; sheaths broad, colourless, 
 distinctly lamellose, even. 
 
 Size. Trichomes -002 mm. diam. 
 
 Hydrocoleum tinctorium, Br. Eabh. Alg. Eur. ii., 294. Ralfs 
 Exs., No. 19. 
 
 On aquatic plants, 
 
 Mr. Marquand says that he has never seen it growing on any other 
 plant than Scirpus fluitans, and he adds : — " I have never seen a vestige 
 of green about it in its natural condition during any period of its exis- 
 tence ; when decaying it becomes pale, and eventually almost white ; 
 when in its best condition it is of a rich chesnut brown. In drying it 
 turns green. In its best condition, when placed in water for twelve hours, 
 it will dye it of a clear rosy purple." 
 
 The following description of this plant has been kindly furnished by 
 Mr. Ralfs :— " In rapid streams on leaves of aquatic plants, it forms a 
 minute continuous covering on leaves of aquatic grasses, giving them a 
 feathery appearance. Colour varying from nearly black to pale reddish 
 brown ; in drying and decay it turns green, and gives a purplish stain to 
 paper. Filaments somewhat mucous, very slender, nearly colourless, 
 cohering at base in fascicles containing 3 to 8 filaments, and by their 
 separation at intervals, simulate branches, and thus gradually reduce the 
 number cohering until they ultimately separate into single ones. The 
 filaments thus appear comparatively stout at the base and gradually to 
 become attenuated upwards. As the apparent branches are given off this 
 is more especially the case, because, from their pale colour, indistinct 
 endoohrome, and closeness of connection, it requires care to detect that 
 they are really fascicled. Besides the elongated filaments there are 
 numerous short ones at the base, together with crowded, somewhat 
 thicker clavate erect bodies. Whether these are the fructification or 
 rudimentary fascicles I am unable to determine." — Malfs. 
 
 Plate 0. fig. 3. Upper portion of fascicle of trichomes X 400. 
 
 Genus 104. I.T>TGrBYA, Ag. em. Thwet. (1875.) 
 
 Filaments enclosed singly in a sheath, simple, or only excep- 
 tionally exhibiting the beginning of ramification where the 
 trichome issues from the side of the sheath ; often combined in 
 a membranaceous stratum. — including Phormidium Kutz. 
 
258 NKMATOGEN^. 
 
 liyngbya aestuazii. Zieb. Danska Algflora. (1839.) 
 
 Trichomes rigid, flexuously curved, blue green, granular, 
 densely interwoven in dark blue green tufts ; joints 3-6 times 
 shorter than their diameter ; scarcely constricted ; sheaths 
 pellucid, hyaline, becoming brownish, at first scarcely lamellose, 
 at length when old becoming distinctly lamellose. 
 
 Size. Trichomes ■025--03 mm. diam., without sheath. 
 
 Lynghya ceruginosa, Ag. Syst. p. 74. Rabh. Alg. Eur. ii., 
 138. 
 
 Lyngbya ft. ferruginea, Harv. Pliyc. Britt., t. 311. 
 
 Lynghya curvata, Rabb. Alg. Eur. ii., 137- 
 
 Lynghya majuscula, Cocks Brit. Seaweeds No. 365. 
 
 In brackish water. 
 
 Plate CI. iuj. 1. ffi, portion of filament X 160 diam. J, extremity 
 of filament, with portion of trichome escaped X 160 diam. c, portion of 
 filament with the trichome divided into hormogones X 330. d, e, hormo- 
 gones X 330, all after Thuret. 
 
 lyngbya littozalis. (fiarm). 
 
 Stratum thin, submembranaceons, mucilaginous, blue green, 
 shortly radiating ; trichomes rigid, flexuous, vividly oscillating, 
 equal ; joints 4-5 times as broad as long, constricted at their 
 junction and hyaline, dissepiments granulated, extreme apiculns 
 straight, broadly rounded, paler ; cell contents pale blue green, 
 very delicately granular. 
 
 Size, Threads •013--015 mm. diam. 
 
 Oscillatoria littoralis, Carm. Alg. App. ; Eng. Fl. v., 375. 
 Harv. Man., 165. Harv. Phyc. Britt. t. 105, fig. o. 
 
 In brackish water, and in rock pools by the shore. 
 
 " Stratum exceedingly thin, slimy, bullated by the extrication of air- 
 bubbles, of a dark green colour, spreading to an indefinite extent over 
 the mnddy bottom of the pool." — Carm. 
 
 Plate CII. fig, 1. Portions of trichomes X 400, from the original 
 specimens. 
 
 lyngbya ochzacea. Thur. Arm. Sci. Nat. (1875) 377. 
 
 Forming cloud-like floating fragile masses of an ochrey 
 colour. Trichomes- very slender, scattered ; joints scarcely 
 visible. 
 
 Size. Trichomes -002 mm. diam., including sheath. 
 
 Kirch. Alg. Schl. 241. 
 
 Leptothrix ochracea, Kntz. Tab. Phyc. i., t. 61, fig. 1. 
 
 Coiiferra ochracea, Dillw. Conf. t. 62. 
 
LYNGBVJ3. 259 
 
 Oscillatoria ochracea, Grev. Fl. Edin. 304. Harv. Man. 
 167. Eng. PI. v., 378. Eng. Bot. ii., 187. Johnst. Fl. 
 Berw. ii., 264. Mack. Hib. 240. Fl. Dev. ii., 57. Gray. 
 Arr. i., 281. 
 
 In boggy pools. 
 
 This species is oommoti in boggy pools " where it occurs in cloud-like 
 masses, scarcely to be called strata, the filaments are very slender and 
 scattered without order. Dillwyn's figure incorrectly represents the 
 filaments as branched." 
 
 Plate OIL fig. 4. Trichomes x 400. 
 
 Lyngbya inundata. (Xitte.) 
 
 Deep blue green, with a whitish grumous membranaceous 
 substratum, trichomes curved rather rigid, pale blue green, 
 rarely fasciculate, sheaths narrow, joints shorter than their 
 diameter, dissepiments naked (not granulated), extreme apex 
 straight obtuse. 
 
 Size. Trichomes -004 mm. diam. 
 
 Phoiviidium inundatum, Kutz. Tab. Phyc. i., t. 45, f. 3. 
 Eabh. Alg. Eur. ii., 116. 
 
 Oscillariaautumnalis,Ca.xia.{^2i,ri\y). Harv. Man. 165. Hass, 
 Alg. 251, t. 72, f. 7. 
 
 Margin of ditches, by moist roads, on flowerpots, &c. 
 
 " Stratum extensively spreading, very dark and lubricous, glossy when 
 dry, filaments remarkably pale, striae not very evident, a variety is com- 
 mon on clayey ground, which occurs in small circular patches about an 
 inch or two in diameter," — Rarvey. 
 
 The filaments in Carmichael's specimens are' not more than half the 
 diameter of those in Lyngiya vulgaris, to which species they are usuallj- 
 referred, 
 
 Flate OIL fi^. 8. Portions of trichomes X 400. 
 
 Lyngbya vulgaris. Kirch. Alg. Sehl. 242. 
 
 Stratum thin, more or less expanded, mucilaginous, dark 
 coloured (olive, brown, yellow, steel blue or purplish) opaque or 
 shining, by age becoming thickened, but rarely lamellose, and 
 without a substratum being formed ; trichomes straight, rigid, 
 distinctly vaginate, joints equal to their diameter or shorter, 
 dissepiments delicately granulated, apex evidently attenuated, 
 now and then somewhat curved, naked. 
 
 Size. Trichomes -0045- -0065 mm. with sheath •006--009 mm. 
 
 Phormidium vulgare, Kutz. Tab. Phyc. i., t. 46, fig. 4. Eabh. 
 Alg. Eur. ii., 119. 
 
 2 o 
 
260 NEMATOGENiE. 
 
 Oscillatoria autumnalis (partly;, Eng. Fl. v., 376. Eng. Bot. 
 ii., 187. Jenn. Tunb. Wells 188. Grev. Fl. Edin. 305. 
 Harv. Man. 165, Mack. Hib., 239. 
 
 Conferva decorticans, Dillw. Conf. t. 26. 
 
 Oscillatoria decorticans, Grev. Fl. Edin. 304. Eng. PI. v., 
 375. Eng. Bot. ii., 187. Jenner Tunb. Wells 188. Harv. 
 Man. 164. Mack. Hib. 239. Hass. Alg. 257, t. 71, f. 10. 
 
 Hvmida decorticans, Gray. Arr. i., 282. 
 
 On moist naked ground after rain. 
 
 Plate OIL fig. 5. Portion of trichomes X 400 ; fig. 6, variety 
 myochrotim x 400: 
 
 Iiyng'bya papyrina. Kirch. Alg. Schl. 241. 
 
 Forming a thin papery stratum, sometimes shortly radiating, 
 with a pallid or brownish iibrillose substratum, formed from 
 the interlaced empty sheaths, trichomes equal, joints nearly 
 equal or a little shorter than their diameter, granulated at their 
 junction, apex obtuse, straight, naked. 
 
 Size. Trichomes ■005--006 mm., with sheath •0075--009. 
 
 Oscillaria papyrina, Bory. Diet. Sci. Sat. 
 
 Phm-midium papyrinum, Kutz. Tab. Phyc. i., t. 41, fig. 3. 
 
 Phormidium papyraceum, Eabh. Alg. Eur. ii., 125. 
 
 Oscillatoria spadieea, Carm. Hass. Alg. 255, t. 71, f. 5, t. 
 72, f. 5. Eng. Fl. v., 378. Harv. Man., 167. 
 
 In streams, torrents, aqueducts, canals, &c. 
 
 The form met with by Carmichael was growing on damp mossy earth. 
 He says *' It occurs in a very thin dark green stratum spreading to the 
 extent of several feet, and is hardly to be distinguished from the mossy 
 earth on which it grows." 
 
 Plate ClI. fig. 7. Portions of trichomes X 400. 
 
 Ziyngbya rapestxis. {Ag.) 
 
 Stratum compact, rather velvety, gelatinous, lamellose, very 
 shortly radiating, bright blue green or becoming dark steel blue, 
 the lower sti-ata becoming discoloured and fibrUlose ; trichomes 
 rigid, rather flexuous, a little torulose towards the apex, joints 
 equal in length and breadth, very finely punctate, dissepiments 
 granulated, extreme apex paler, sometimes bearded. 
 
 Size. Trichomes •007--008 mm. diam. 
 
 Phormidium nipestre, Kutz. Tab. Fhvc. i., t. 49, fig 4 Rabh 
 Alg. Eur. ii., 122. 
 
 Oscillaria riipestris, Ag. Syst. p. 63. Hass. Alg. 254. t 
 72, f. 11. Grev. Sc. Crypt. Fl. t. 246. Eng. Fl v 877 
 Harv. Man. 166. r. , ■ 
 
LYNGBY^. 261 
 
 On moist rocks where the water is constantly trickling, and in 
 mountain streams. 
 
 Oarmiohael writes of hia speoimena, " Sfcratam extensive, slimy, re- 
 markably tough and elastic, black on the sarfaoe, ash-ooloured under- 
 neath, when dry blackish green. Filaments pale green, straight, or 
 variously curved, radiating, but not equally in all directions." 
 
 Plate CI. Jig. 2. Portions of trichomes X 400. 
 Iiyngbya corium. (Ag.) 
 
 Stratum toughly membranaceous, compact, brown, steel blue 
 or greenish, interwoven forming a mucilaginous membrana- 
 ceous substratum ; trichomes straight or flexuous, rather rigid, 
 olive or brown, then yellowish, joints not more than half as long 
 as broad, beautifully transversely punctate, granulated, apex 
 conically attenuated, bearded. 
 
 Size. Trichomes 'OOT-'OOS mm. diam. 
 
 Phormidiuni corium, Ag. Syst. p. 64. Eabh. Alg. Eur. ii., 
 126. 
 
 Oscillatoria corium, Hass. Alg. 252.. Eng. Fl. v., 377. 
 Harv. Man. 166. Eng. Bot. ii., 187. Grev. Fl. Edin. 303. 
 Mack. Hib. 240. 
 
 On the rocky bottom of alpine rivulets. 
 
 " Stratum thick, tough, dull brownish, occaaionally streaked with pale 
 green, which in some varieties is the prevailing colour, slightly glossy 
 when dry ; filaments slender. In some situations it radiates in fascicles 
 from its whole upper surface; in others it is found almost denuded 
 of radii, and forming a compact leathery stratum." — Ha/rvey. 
 
 Plate CIl. fig. 2. Portions of trichomes X 400. 
 
 Lyngbya tuzfosa. {Oarm.) 
 
 Forming a thick intensely green stratum, with a tough, slimy, 
 ochre-coloured substratum. Trichomes slender, more or less 
 curved, and mostly hyaline at the point ; joints not more than 
 half as long as broad, distinct. 
 
 Size. Trichomes '008 mm. diam. 
 
 Oscillatoria turfosa, Carm. in Harv. Man. 164. Hass. Alg. 
 253, t. 72, f. 6. 
 
 On floating sods in old turf pits. 
 
 " This species grows in a thick, intensely green layer, over a tough, 
 slimy, ochre-coloured substratum. It entirely enveloped the sods, some 
 of which were a foot and a-half in diameter. Filaments very slender, 
 more or less curved, and mostly hyaline at the point." — Carm. 
 
 Plate Cll. fig. 3. Portions of trichomes X 400, from the original 
 specimens. 
 
262 
 
 NEMATOGEN^. 
 
 Iiyngbya subfusca. (Ag. Syst. p. 64.) 
 
 Substratnm velvety, fibrillose, tawny, becoming yellowish, 
 forming a firm compact stratum, of a violet or steel blue colour, 
 changing to brownish ; trichomes rigid, straight, joints about 
 half as long as broad, with a double row of points at the com- 
 missure, apex rather obtuse, naked. 
 
 Size. Trichomes "008 mm. diam. Thinner form, trichomes 
 •006--007 mm. diam. 
 
 Fhoi-midium subfuscum, Eabh. Alg. Eur. ii., 125. 
 
 On stones in mountain streams. 
 
 Plate CI. fig. 3. a, portions of trichomes X 400, from Scotoli speci- 
 mens, b, portions of trichomes from a thinner form X 400. 
 
 Genus 105. STHIFLOCA. EuU. (1843.) 
 
 Trichomes ai-ticulate, simple, or only exhibiting the beginning 
 of ramification, more or less distinctly vaginate, ascending from 
 a prostrate base, agglutinated, together in erect or anastomos- 
 ing fascicles, or wick-like bundles, more or less procumbent, 
 coalescing, and often involved in a matrical gelatin. 
 
 Symploca lucifuga, Han.', in Eng. Ft v., 373. 
 
 Dark sernginous green, fascicles about two lines high, ap- 
 proximate, subuliform, apex at length penicillate ; trichomes 
 single or twin, sernginous, joints equal or a little longer than 
 broad, distinctly granulated, sheaths broad, pellucid, colourless, 
 quite smooth. 
 
 Size. Trichomes •0035-'004 mm. diam., including sheath 
 •01 mm. 
 
 Eabh. Alg. Eur. ii., 155. 
 
 Oscillatoria lucifuga, Hass. Alg. t. 65, f. 5, 6. Harv. in 
 Eng. PI. v., 373. 
 
 Galothrix lucifuga, Carni. MSS. 
 
 On pastures and heaths, on decayed alder trunk. 
 
 " Stratum spreading dull blackish green, bristling all over with minute 
 erect fascicles about one third of a line high. Filaments thickish, 
 fiexuons, strongly agglutinated together, annulated within, pale 
 yellowish." — Harvey, 
 
 Plate cm. fig. 2. a, portion seen with a pocket lens. J, trichomes 
 X400. 
 
LYNGByjE. 263 
 
 Symploca Ralfsiana, Kutz. Tab. Phyc. i, t. 74,/. 4, 
 
 Steel blue or olive becoming blackish, fascicles as much as 
 an inch high, densely aggregated, often coalescing, subuliform, 
 straight, trichomes pale blue-green or steel blue, densely 
 agglutinate, distinctly articulated, somewhat beaded about the 
 apices, joints equal or a little longer than broad, cell-contents 
 granular, sheaths broad, pellucid, homogenous. 
 
 Size. Trichomes •0035-*004 mm. diam. 
 
 Rabh. Alg. Eur. ii., 157. , 
 
 Oscillaria Friesii, Harv. Eng. Fl. v., 373. Harr. Man. 
 162. Hass. Alg. p. 259. Mack. Hib. 238. 
 
 Oscillatoria Bangii, Carm. Grev. PI. Ed. 303. 
 
 Scytonema Bangii, Lyngb. Hydro. Dan. t. 28. 
 
 Over running mosses in shady sub-alpine situation. 
 
 " Stratum 2-3 inches broad, bright aernginous green; Filaments 
 closely interwoven into erect elongated tooth-like fascicles, an inch or 
 more in height, pale green under the microscope, annnlated within, with 
 a broad limb or border, well marked by its erect spinulose habit." — 
 Ha/rvey. 
 
 Plate cm. fig. \. a, portion as Been with a pocket lens. 6, trichomes 
 X 410. 
 
 Genus 106. FLECTONEKA. TMr. (1875.) 
 
 Filaments branched, ramifications produced by the branching 
 of the trichome outside of the sheath, very irregular, and often 
 germinate as in Scytonema. 
 
 Plectonema miirabile, Thur. Ann. 8ci. Nat. (1875) 377. 
 
 Forming floccose tufts, blue-green, now and then turning 
 brownish, trichomes with pseudo-branches usually in pairs and 
 parallel ; joints shorter than their diameter, granular sheath 
 narrow, colourless or yellowish, quite smooth. 
 
 Size. Filaments -021 mm. with sheath. 
 
 Born, and Thuret, Notes Alg. ii., p. 135, t. 33. 
 
 Conferva mirdbilis, Dillw. Conf. t. 96. 
 
 Calothrix Brebissonii, Kutz. Tab. Phyc. ii., t. 30, f. 4. 
 
 Calothrix atrovirens, Harv. Man. 159. 
 
 Calothrix mirabilis, Ag, Syst. 72. Rabh. Alg. Eur. ii., 271. 
 Hass. Alg. 243, t. 69, f. 1. Eng. Fl. v., 369. Harv. Man. 159. 
 
 Elisa ndrabilis, Gray. Arr. i., 283. 
 
 In small streams. 
 
 Plate CIV fig. 1. a, portion of trichome x 330. 6, portion with 
 ,„ single branch X 330 after Thuret. 
 
264 
 
 NEMATOGEN^. 
 
 Plectonema Sizchneri, Coolce, ChemUea xi., p. 75. 
 
 At first attached, but soon floating, and forming subglobose 
 woolly tufts, of a dark bluish green, changing to olivaceous. 
 Tufts from half an inch to an inch in diameter. Trichomes 
 radiating, with simple (rarely germinate) branches ; joints one 
 third or one fourth as long as broad. 
 
 Size. Filaments ■012-*015 mm. diam., with sheath. 
 
 Plectonema mirabile, Kirch. Alg. Schles. p. 229 (scarcely of 
 Thnret). 
 
 In ornamental water. Pleasure grounds, Kew. 
 
 The filaments are ranch thinner than in .P. rnirabile and the branches 
 issne singly from the sheath, and not in pairs, as in that species. From 
 the dimensions given by Kirohner it seems probable that this is the 
 species to which he has given the name of P. mirabile. 
 
 Plate Cir. fig. 2. a, tuft, natural size. 6, trichomes X 400. 
 
 FAMILY III. SCYTONEMEJE. 
 
 Filaments with lateral ramifications in which some of the 
 cells change into heterocysts. 
 
 This family is divisible into two sections according to the direction 
 of the multiplication of the cells. 
 
 * Cells only multiplying in the direction of the length of the filament. 
 Scytonema, Fetalonema, Symphyosiphon, Tolypothzix, 
 Cystocoleus. 
 
 ** Cells multiplying as well in the direction of the breadth of the 
 filament, at least where the branches, which ^e always produced by 
 lateral multiplication, originate. 
 
 Stigonema, Fischeza, Haplosiphon. 
 
 The last section inctndes many very doubtful forms, which will pro- 
 bably, as their development becomes better known, be transferred to 
 Lichens, of which they are presumably an imperfect condition. 
 
 Genus 107, SCYTONEMA. Ag. (1824.') 
 
 Sheath enclosing a single trichome, ramifications produced 
 by the deviation of the trichome, which emerges from the side 
 of the sheath. Ramifications usually geminate, produced by a 
 fold of the trichome which ruptures outside of the sheatli, and 
 gives origin to two filaments given ofi^ at a right angle. 
 Heterocysts scattered here and there in the trichome, without 
 any evident relation to the ramifications. 
 
SOYTONBMEJI. 265 
 
 Scjrtonema myochrous. Ag. Syst. p. 40, Jfo, 13. 
 
 Stratum thin, woolly, dark brown (now and then rather 
 silky) ; trichomes very thick, brown, lucid, slightly curved, 
 ascending, blue-green within, reddish at the apex (5-6 terminal 
 joints), distinctly articulate, pseudo-branches for the most part 
 in pairs, sometimes very long, flaccidly erect, about half the 
 thickness of the trichomes ; sheath of the trichomes thick, dis- 
 tinctly lamellose, firm, beautiful yellow-brown, surface quite 
 smooth, that of the branches paler, often colourless at the tips, 
 closed and obtusely rounded, heterocysts oblong or sub-cylindri- 
 cal, colourless, about equal to the inner diameter of the 
 trichomes. 
 
 Size. Cells '01 mm. diani., with sheath -03 mm. diam. 
 
 Rabh. Alg. Eur. ii., 254. Hass. Alg. 237, t. 68, f. 2. 
 Jenn. Tunb. "Wells, 188. Gray. Arr. i., 285. Eng. Bot. ii., t. 
 2515, t. 2516. Kirch. Alg. Schl. 225. Harv. Eng. Fl. v., 
 365. Harv. Man. 155. Mack. Hib. 236. 
 
 Conferva myochrous, Dillw. Conf. t. 19. Eng. Bot. i., t. 
 1555. 
 
 On moist rocks. 
 
 Plate CV. fig. 1. a, threads magnified about 60 diam. ; i, portion of 
 same X 400 ; c, hormogonea X 400. 
 
 Scytonema natans. Breb. m KuU. Tab. Phyc. II., t. 22, /. 1. 
 
 Ploccose tomentose, green then brown or olive, trichomes 
 slender, elongated, becoming brownish, internally seruginous 
 green, distinctly articulate, joints nearly equal, gi'anular, pseudo- 
 ramuli often in pairs, very slender, more or less distant, very 
 shortly articulated, sheaths firm, lamellose, yellow or brownish, 
 I'arely uncoloured, branches paler, or colourless, indistinctly 
 lamellose, heterocysts interspersed, oblong, or ovoid, pellucid. 
 
 Size. Threads with sheath "025 mm., without sheath -007 
 mm. 
 
 Rabh. Alg. Eur. ii., 253. Kirch. Alg. Schl. 224. 
 
 In stagnant water. 
 Plate CV. fig. 2. Portion of triohome with sheath X 400 diam. 
 
 Sc3rtoueina cineieum. Meneg. in Kutz. Spec. 303. 
 
 At first pulvinate, cinereous green, then confluent, forming a 
 more or less tomentose pulverulent stratum (becoming pale blue 
 when dry), now and then violet or purplish ; trichomes very 
 fragile, elongated, flexuose and curved, loosely interwoven, 
 sparingly branching, indistinctly articulate, internally dingy, 
 
 2 p 
 
266 
 
 NEMATOGEN^. 
 
 sernginous green, joints shorter than broad ; sheaths thick, 
 golden brown, often encrusted with deposit of lime. 
 
 Size. Trichomes 008 mm., including sheatk 01 mm. 
 
 Kirch. Alg. Schl. 225. Eabh. Alg. Eur. ii.. 247. 
 
 Scytonema Julianum, Wittr. & Nordst. Alg. Exs., No. 273 a. 
 
 Drilosiphon muscicola, Kntz. Sp. 302. 
 
 Oscillaria cyanea, Hass. 4.1g. 248. Eng. Fl. y., 374. Harv. 
 Man. 163. 
 
 Conferva cyartea, Eng. Bot. ii., t. 2578. 
 
 Humida cyanea, Gray. Arr. i., 282. 
 
 On walls, stones, overrunning moss, &c. 
 
 Found on the walla of warm honses in the Koyal Botanic Gardens at 
 Kew, and in Regent's Park. This is eridently the Conferva cyanea of 
 Bnglish Botany fonnd on damp walls in- churches, &c. " On the wall it 
 is conspicuous for its light sky-blue colour, like some sort of .Vifor. 
 Under a high magnifier, and when moistened, it is found to consist of 
 minute even simple entangled threads, coated with a frequently inter- 
 rupted covering of a dull glaucous green hue, under which the thread 
 itself appears of a lighter glaucous bluish colour, very even in thickness, 
 and surface consisting of scarcely distingnishable joints about as broad 
 as they are long." — Smith. 
 
 Bornet and Thuret refer this to a variety of Scytonema Hoffmanni, 
 whilst Kirchner retains Meneghini's specific name, which Thuret thinks 
 to belong to Scytonema ocellatum, Lyngbye. 
 
 Plate Cf^I.fig. 1. a, trichomes X 400; J, portions of same X 400 ; c, 
 hormogones X 400. 
 
 Scytonema intezruptam. Th^c 
 
 Intense blue-green, foiming a stratum of the same colour ; 
 sheath cellular, and furnished throughout its entire length with 
 numerous branched and anastomosing rootlets ; trichomes dis- 
 tinctly annulate, interrupted here and there hy heterocysts, 
 branches in pairs arising from the protruded trichome. 
 
 Size. Nowhere stated. 
 
 Rhizonema interruptum, Thwaites .in Eng. Bot. ii. Supp., t. 
 2954. 
 
 Calothrix tnterrupta, Carm. Eng. Fl. v., 368. Harv. Man. 
 158. 
 
 Stigonema interruptum, Hass. Alg. 229, t. 69, f. 2. 
 
 In wet heathy places, coating mosses, &c. 
 
 We have seen no specimen of this, which is evidently a close ally of 
 S. cmereum. The figure is reproduced from English Botany. 
 
 Plate CVl. fig. 2. Scytonema interruptum, after the figure t. 2954, 
 English Botany. Considerably magnified, presumably about 360 diam. 
 
SOYTONEMB^. 267 
 
 Genus 108. FETALONEMA. Berh. (1832.) 
 
 Ti'ichomes enclosed in a very broad striate membranous 
 sheath, which forms a transparent layer, resembling a hyaline 
 wing. 
 
 Threads as in Scytonema, with the sheath very broad, forming a 
 transparent layer around the triohome. 
 
 Petalonema alatum. Berk. Qlean. t. 7, f. 2. 
 
 Forming a thin brown stratum. Trichomes small, a few 
 lines only in length, winged, obtuse, with numerous striae, when 
 taken in conjunction with the wings or membranous expansions, 
 they are linear and plane. Each wing is about thrico the 
 breadth of the proper filament, of a white colour, somewhat 
 transparent, of a bright yellow next the filament, and exhibiting 
 under a favourable light a numerous series of transverse lines 
 or folds. Endochrome of the central thread greenish and 
 septate. 
 
 Size. Trichomes '01 mm., with sheath from "05 to '12 mm. 
 
 Hass. Alg. 238, t. 68, f. 6. Harv. Man. 168. 
 
 Arthrosiphon alatus, Rabh. Alg. Eur. ii., 265. 
 
 Arthro siphon Grevillei, Kutz. Sp. Alg. 311. Fischer Nost. 
 f. 10. 
 
 Oscillatoria alata, Grev. Sc. Orypt. Flora, t. 222. 
 
 On rocks exposed to the trickling of water. 
 
 Plate CVII, fig. 1, Upper portion of triohome with sheath X 400 
 diam. 
 
 Genus 109. STMFHYOSIPHON. XuH. (1843.) 
 
 Trichomes as in Scytonema. Filaments agglutinated in erect 
 wick-like bundles. 
 
 Symphyosiphon Hoffmanni. Kidz. Tab. Phyo. ii., t. 43, /, 3. 
 
 Terrestrial, resembling a Symploca in habit. Tufts small, 
 ascending, dark brown ; trichomes simple, erect, loosely col- 
 lected in pointed fascicles, internally pale seruginous green, 
 sometimes interrupted, joints delicately granulose, inferior 
 cylindrical, thin, superior thicker and more or less swollen. 
 Sheath firm, broad, attenuated upwards, rarely acute, colourless, 
 or yellowish towards the base. Heterocysts intercalated, 
 globose, hyaline. 
 
 Size. Trichomes '01 mm. diam., with sheath •012-'014 mm. 
 
 Scytonema Hoffmanni, Agardh Syst. p. 40. Eabh. Alg. 
 Eur. ii., 259. 
 
268 
 
 KEMATOOEN^. 
 
 On naked ground, overruning mosses, &c. 
 
 Found in Bome qnantity in one of the stoves of the Eoyal Botanic 
 Gardens, Begent's Park, forming a dark velvety stratam on the stones, 
 walls, &o. 
 
 Plate C7II. fig. 2. a, slightly enlarged, as seen by aid of a pocket 
 lens ; b, trichomes X ^C ; c, portion of same ; i, hormogones X 400. 
 
 Genus 110. TOLYPOTKRIS. Kutz. (1843.) 
 
 Trichomes spuriously branched, pseudo-branches spreading. 
 Ramifications rarely geminate, oftener solitary, and originating 
 at a point where the continuity of the trichome is interrupted by 
 heterocysts, one or several heterocysts placed directly above 
 each branchlet. 
 
 Tolypothrix flaccida. KuU. Phye. Gen., p. 228. 
 
 Caespitose, dark blue-green, trichomes and pseudo-branches 
 elongated, flaccid, arising from a prostrate base, internally pale 
 blue-green, either interrupted or torulose, distinctly articulate 
 (when treated by iodine), joints a little shorter than broad, 
 sheaths colourless, hyaline, rather broad, heterocysts towards 
 the base, subglobose or oblong, two or three together, colour- 
 less. 
 
 Size. Trichomes -01 mm. 
 
 Eabh. Alg. Eur. ii., 227. Kutz. Tab. Phyc. ii., t. 32, f. 2. 
 
 In pools, &c. 
 Plate CVllI.jig. 1. Portions of trichomes X 400 diam. 
 
 Tolypothzix distoxta. Kviz. Tab. Phye. il., t. 33,/. S. 
 
 Caespitose floccose, bright blue-green, now and then becoming 
 pale, trichomes and pseudo-branches very loosely interwoven, 
 internally blue-green, sometimes apparently continuous, some- 
 times distinctly articulate ; joints equal or a little shorter than 
 their diameter ; sheaths broad, colourless, rarely pale yellow ; 
 heterocysts at the base, or inteijected, subglobose or oblong, 
 often 2-3 together. 
 
 Size. Trichomes "012 mm. 
 
 Eabh. Alg. Eur. ii., 275. Kirch. Alg. Schl., 228. 
 
 Conferva distorta, Dillw. Conf. t. 21. Eng. Bot. t. 2577. 
 
 In swamps. 
 
 " Found occasionally in boggy pools, growing on thick continuous 
 tufts, on decaying grass, and about the stems of aquatic plants, upon 
 small fragments of which it often floats in the autumn on the surface of 
 the water." 
 
 Plate CVI2I. fig, 2 Portion of trichome with hormogone x 400 diam. 
 
SCYTONKMB/E. 
 
 269 
 
 Tolypothrix aegagzopila. Mutz. Tab. Fhjc. II., t. 32, f. 3. 
 
 Tufts an inch or more broad, somewhat rounded, bright blue 
 green or greenish olive ; trichomes and pseudo-branches loosely 
 interwoven, internally pallid blue green, continuous or dis- 
 tinctly articulate, joints equal or a little longer than their 
 diameter ; sheaths narrow, hyaline, colourless, heterocysts 2 
 or 3 (rarely more) in a series, oblong, hyaline. 
 
 Size. Trichomes •01-'012 mm. 
 
 Eabh. Alg. Eur. ii., 274. Kirch. Alg. Schl., 227. 
 
 Tolypothrix punctata, Hass. Alg. 240, t. 69, f. 3. 
 
 In standing pools. 
 
 Plate CCK. fig. 1 . Portion of triohome with hormogonea X 400 ; 
 b, 0, hormogones after Thuret j d, e, spores, after Borzi. 
 
 var. e, pygmaea. Kviz. 
 
 Tufts small, blue green or brownish, trichomes and pseudo- 
 branches slender, very losely interwoven, joints a little shorter 
 than broad, sheaths narrow, colourless or yellowish. 
 
 Size. Trichomes •007-'008 mm, with sheath "01 mm. 
 
 Kirch. Alg. Schl., 228. 
 
 Tolypothrix pygmcea, Kutz. Tab. Phyc. ii., t. 31, f. 4. Babh. 
 Alg. Eur. ii., 275. 
 
 Plate GIX. fig. 2. Portion of trichomes with hormogones X 400. 
 
 var. /, muscicola. Kutz. 
 
 Csespitose, blue green or brownish, trichomes and pseudo- 
 branches thicker, elongated, loosely intricate, distinctly articu- 
 lated, points a little shorter than broad, sheatfis very delicate. 
 
 Size. Trichomes -OOS-'Oll mm. 
 
 Kirch. Alg. Schl, 228. 
 
 Tolypothrix muscicola, Kutz. Tab. Phyc. ii., t. 31, f. 5. Rabh. 
 Alg. Eur. ii., 275. 
 
 On mosses, &c. 
 
 Tolypothzix coactilis. Kutz. Tab. Phyc. ii., t. 32, /. 1. 
 
 Fasciculate, caespitose, green then brightly seruginous, tri- 
 chomes and pseudo-branches slender, internally pallid, 
 sruginous, sometimes distinctly, sometimes indistinctly articu- 
 late, granulose, joints about half their diameter in length ; 
 sheaths very narrow, very thin, homogenous, colourless, hya- 
 line; heterocysts oblong, twin or ternate, colourless. 
 
 Size. Trichomes "01 mm., with sheath a little more. 
 
 Kirch. Alg. Schl., 228. Rabh. Alg. Eur. ii., 274. 
 
 Tolypothrix distorta, Hass. Alg. 240, t. 69, f. 4. Eng. Bot., 
 t. 2521. Ralfs. Alg. Ex. No. 20. 
 
270 NEMATOGENiE. 
 
 Conferva distorta, Dill. Conf., t. 22, /. A. E 
 Calothrix distorta, Hary. Man. 158. Mack. Hib. 237. 
 Elisa distorta, Gray. Arr. i., 282. 
 
 . In ponds and lakes. 
 
 Plate CIX. jig. 3. Portions of Triohomes X 400. 
 
 Tolypothzix cinhosa. (£iirm.) 
 
 Floating c»spitose, olive, or blue-green, becoming brownish ; 
 trichomes nearly simple, rather stout, distinctly articulate, 
 pallid blue-green, joints finely granular, one-half or one-third 
 as long as broad ; sheaths moderately narrow (rather broad in 
 some of the older trichomes), indistinctly lamellose, smooth ; 
 heterocysts scattered. 
 
 Size. Trichomes •012--014mm., with sheath •02--025 mm. 
 
 Scytonema cirrhosum, Carm. Eng. Fl. v., 366. Harv. Man., 
 155 (not of Eng. Bot. ii., t. 2920). 
 
 Arthronema cin-hosum, Hass. Alg. 238, t. 68, f. 7. Eabh. 
 Alg. Eur. ii., 267. 
 
 In mountain lakes. 
 
 " It forms flexnons tnf ts of brown, very slender threads, proceeding in 
 fascicles from membranons snb-erect sheaths, and oontaiaing a single 
 row of cells scarcely so long as broad." — Carm. 
 
 Plate CVIII. fig. 3. Portions of trichomes X 400 j a, hormogone 
 X400. 
 
 APPENDIX. 
 
 Although included by Thuret and Bomet, and also by 
 Kirchner,* with Algse, it can scarcely be doubted that all the 
 members of the genera Stigonema (or Sirosiphori) «nd Hapalo- 
 siphon mnst be transferred to the Lichens. They are included 
 here in the form of an appendix, for the satisfaction of students, 
 who would naturally expect some reference to them in a work 
 of this kind. At the same time we have availed ourselves of 
 the opportunity to add figures, and descriptions, of two or three 
 uncertain species, which have been recorded as British, under 
 new and unknown genera. 
 
 Genus 111. STIGONEHA. Ag. (1824.) 
 
 Cells of the trichome often geminate or ternate, in conse- 
 qoence of their lateral multiplication, or even forming trans- 
 verse, several-celled bands. Sheath large. Cells surrounded 
 with a thick membrane, very prominent in the old filaments. 
 Hormogones originating in lateral branchlets formed of a single 
 row of cells. 
 
scytonbmS^. 271 
 
 Stigonema ocellatum. Thur. Ann. Sci. Nat. 1875, i., 377. 
 
 More or less expanded, woolly-tomentose, dark olive brown, 
 cells of the trichome for the most part biseriate, sub-globose, 
 or oblong-compressed, equal or one-third as long as broad, 
 filled with a granular blue-green plasma; sheaths very thick, 
 lamellose, dark golden brown, external stratum now and then 
 paler, cells of the branches for the most part "uniseriate, ocell ate, 
 sometimes much elongated, apex obtuse, rounded, seldom again 
 branched, sheaths colourless or yellowish, quite smooth. 
 
 Size. With sheath about -04 mm. Cells ■01--012 mm. 
 
 Kirch. Alg. Schl. 230. 
 
 Sirosiphon ocellatus, Kutz. Tab. Phyc. ii., t. 37, f. 2. Eabh. 
 Alg. Eur. ii., 286. 
 
 Hassallia ocellata, Hass. Alg. t. 67, f. 2, 7, 6. Fischer 
 Nost., fig. 11. 
 
 Conferva ocellata, Dillw. Conf. t. D. Eng. Bot. i., t. 2.530. 
 
 Scytonema ocellatum, Harv. Eng. Fl. v., 364. Harv. Man. 
 154. Grev. Fl. Ed. 302. Gray. Arr. i., 285. Eng. Bot. ii., 
 t. 2514. 
 
 On inundated ground, in swamps and moors. 
 
 Plate ex. fig. 2. Portion of extremity of trichome X 400. 
 
 Stigouema Bouteillii. {Breb. Ann. Sci. Nat.) 
 
 Tnfts small, immersed, cushion-like and rounded, dark brown, 
 trichomes very short, variously ciirved and contorted, olive, or 
 golden brown, sparsely branched, sometimes simple, internally 
 sometimes interrupted, formed from one series of cells one-third 
 or one-fourth as long as broad, branches unilateral, very short, 
 arched, sheaths narrow, colourless or very pale yellow, hyaline 
 and even, or with the outer stratum falling away in fibrils. 
 
 Size. Trichome •04--06 mm. Cells -01, with envelope -02 
 mm. 
 
 Sirosiphon Bouteillii, Breb. & Desm. in Ann. Sci. Nat. ser. 
 4, Vol.iv., p. 2. 
 
 On calcareous rocks and chalky clififs. 
 
 Plate ex. fig. 3. Portion of trichomes X 4O0. 
 
 Stigonema pauniforme. Kirch. Alg. ScJd. 230. 
 
 Forming a thin tomentose stratum, more or less expanded, 
 dark brown, trichomes ascending, very much branched, variously 
 curved, branches unilateral, here and there fasciculate, often ab- 
 breviated, rounded at the apex, internal cells pale blue green, 
 granulose, globose then compressed, arranged in a single, rarely 
 
272 
 
 NEMATOGENiE. 
 
 in a double series, sheaths narrow, brown or yellow brown, paler 
 at the tips or almost colourless. 
 
 Size. Trichomes 'OSS-'OS mm. 
 
 Eng. Fl. v., 363. Hass. Alg. 229, t. 66, f. 4, 5. Harv. 
 Man. 153. 
 
 Sirosiphon panniformis, Kutz. Tab. Phyc. ii., t. 36, f. 2. 
 
 Scytonema pannifoiine, Ag. Syst. p. 39. 
 
 On rocks, stones, &c. ' 
 Plate ex. fig. 4. Portion of trichomes X 400 diam. 
 
 Stigonema mamillosum. (Ag.) Kutz. Tab. Phyc. u., t. 37, /. 4. 
 
 Forming continuous tufts several inches in diameter, branches 
 simple, their diameter being greatest in the middle, and beset 
 on all sides with mamillae of various sizes. 
 
 Size. Trichome -Oe-'l mm., very variable. 
 
 Kirch. Alg. Schl. 229. Eabh. Alg. Eur. ii., 291. Eng. Fl. 
 v., 363. Hass. Alg. 228, t. 66, f. 2, 3. Harv. Man. 153. 
 Mack. Hib. 236. 
 
 Rocky bottoms of sub-alpine rivulets. 
 
 Plate CXI. fig. 3. Portion of young trichome X 400, becoming more 
 opaque with age. 
 
 Stigonema compactum. Kirch. Alg. Schl. 230. 
 
 Forming an expanded compact tomentose dark brown stratum, 
 trichomes and branches ascending, a little attenuated at the 
 apices, obtuse, internally formed of a single, rarely a double 
 series of cells, which are torulose and almost moniliform, 
 diameter and length nearly equal, filled with a pale blue-green 
 granular plasma, sheaths firm, golden brown, heterocysts sub- 
 globose or oblong. 
 
 Size. Trichomes •015-'016 mm. 
 
 Sirosiphon compactus, Kutz. Tab. Phyc. ii., t. 36, f. 3. Rabh. 
 Alg. Eur. ii., 287. Leight. Lich. Flora, p. 9. 
 
 Hassallia compaeta, Hass. Alg. 232, t. 68, f. 3. 
 
 Scytonema compactum, Eng. Fl. v., 365. Harv. Man. 154. 
 Grev. Ed. 302. 
 
 On wet rocks. 
 
 Plaie CXI. fig. 4. Portions of trichomes X 400 diam. 
 
 Stigonema tuzfaceum. {Berk. Eng. Sot. Supp. t. 2826, f. 1.) 
 
 Pulvinate, deep olivaceous black, 2 lines thick. Trichomes 
 very thick, much branched, golden yellow, becoming brownish, 
 
SOYTONBME^. 273 
 
 variously curved, branches polymorphous, varying in thickness 
 according to age, obtusely rounded at the apex, cells in several 
 series, from 2 to 4 rows in the ramuli, sheaths thick, yellow 
 brown, hyaline. 
 
 Size. Trichomes ■025-'03 mm. 
 
 Sirosiphon pulvinatus, Breb. in Kutz. Spec. 317 (1849). 
 Eabh. Alg. Eur. ii., 290. 
 
 Hassallia turfosa, Hass. Alg. p. 232 (184.0). Kutz. Sp. p. 
 318. 
 
 Scytonema turfaceum, Eng. Bot. ii., t. 2517, f. 1. 
 
 Dematium turfaceum, Link. Spec, i., 134. 
 
 On the ground in heathy places and on rocks. 
 
 Berkeley says that this Alga was named by Klofcsch as Dematium 
 turfaceum, Link., " which there is every reason to believe is correct." 
 " It is," he says, " a trae Scytonema." As far as we have been enabled 
 to trace it, it seems to be the same as the Sirosiphon pulvinatus of 
 Brebisson. The specifto name of turfaceum has undoubted priority. 
 
 Plate CXI. fig. 2, Portions of trichomes x 400 diam. 
 
 Stigonema saxicolum. (,Naeg, in Kutz. Spec. 316.) 
 
 Forming a thin dark olive velvety stratum. Trichomes 
 minute, curved, variously branched, closely crowded into a thin 
 dark crust or evenly scattered tufts ; sheath narrow, fuscous, 
 cells in a single series, growing denser and nucleate with age. 
 
 Size. Trichomes •018-'02 mm. 
 
 Sirosiphon saxicola (Nag.). Johnson in Grevillea xii., p. 
 76. Fischer Nost. fig. 13. 
 
 On damp rocks, or rocks down which water trickles. 
 
 Plate CXI. fig. 1. Abbreviated trichomes X 400, seldom exceeding 
 this in size. 
 
 Stigonema minutum. ITass. Alg. 230, t. 67,/. 3, 4. 
 
 Spreading in a black suborbicular crust, or scattered in little 
 tufts. Trichomes minute, erect, rigid, flexuous, fastigiate 
 branches short, obtuse, sheath rather broad, fuscous ; cells 
 usually in a single series. 
 
 Size. Trichomes -02- -03 mm. 
 
 Scytonema minutum, Harv. Eng. Fl. v., 365. Harv. Man. 
 155. Mack. Hib. 236. 
 
 On moist rocks in Alpine districts. 
 
 Figured from the original specimen of the English Flora in the Kew 
 Herbarium. 
 
 Plate CJ.. jig. 1. Portion of triohome, nearly complete, X 400 diam, 
 
 2 Q 
 
274 NEMATOGENMO. 
 
 Genus 112. HA.FAI.OSIPHON. Naij. (1840.) 
 
 Trichomes formed mostly of a single row of cells, sheath 
 slender. Aquatic plants, looking like Tolypothrix. 
 
 Hapalosiphon byssoidens. Kirch. Alg. Schl,, 231. 
 
 Tufts compact, dark olive, trichomes ascending, rigid, oliva- 
 ceous, sparsely branched, containing cells arranged in a single 
 series. Cells at first rounded quadrate, equal in length and 
 breadth, becoming when older divided and shorter, one-third or 
 one-fourth the length of their diameter ; sheath very thick, 
 distinctly lamellose, golden yellow, attenuated and obtuse at the 
 apex. 
 
 Size. Trichomes •025--03 mm. diam. Cells -012 x -01 
 mm. 
 
 Sirosiphon tinincicola, Rabh. Alg. Eur. ii., 286. Hedwigia 
 i., p. 47, t. ix., f. 3. 
 
 Hassallia hyssoidea, Hass. Alg. 232, t. 67, f. 5. 
 
 Scytonema byssoideum, Harv. Eng. Fl. v., 366. Berk. Glean., 
 t. 19, f. 1. Harv. Man. 156. 
 
 On trunks of beech, &c. 
 
 Plate CXI. fig. 5. Portions of trichomes X 400 diam. 
 
 SPECIES FOR EX QUIRT. 
 
 Dasygloia amorpha. TJiwaites. 
 
 Gelatinous, amorphous, sheaths of the trichomes thick, muci- 
 laginous, cohering, slightly branched ; internal trichomes blue- 
 green, slender, simple, septate. 
 
 Size. Not indicated. 
 
 Dasygloia amorpha, Thwaites in Eng. Bot. ii. Supp., t. 
 2941. 
 
 In bogs. 
 
 Coalescing in a solid gelatinons mass, as large as a swan's egg. The 
 filaments, quite at the base of the plant, have rathei* a membranous 
 than gelatinous sheath, and closely resemble those of a I/yngJn/a, in 
 consequence of which the base of the mass is green, but in the centre of 
 the plant each filament is furnished with a very thick colourless gela- 
 tinous sheath, which is firmly coherent with those in contact with it. 
 Towards the periphery of the plant these sheaths assume a brown 
 colour, and become somewhat separate and distinct, rendering the sur- 
 face shaggy. Occasionally the tips of the filaments are wound spirally 
 round the portion beneath them. 
 
 Mate CXn. fig.l. a, portion of gelatinous mass, natural sizej b, 
 threads, with gelatinous sheaths, magnified ; c, portion of trichome, with- 
 out sheath, further magnified — all after Thwaites. 
 
OALOTEICHE^. 275 
 
 Petronema fzuticulosum. Thmaites. 
 
 Plants densely CEespitose, erect, somewhat regularly branched, 
 branches free, witb obtuse rounded apices, and each with a 
 heterocyst at the base. Endochrome annulated, increasing in 
 diameter towards the apices of the filaments. 
 
 Size. Fronds -2 mm. long, trichomes '004 mm. diam. 
 
 Pitronema fruticulostmi, Thwaites, Eng. Bot. ii., Supp., t. 
 2959. 
 
 Scytonema cnistaceum, Ag. Syst., p. 39 {fide. spec, in Berb. 
 Hook.). 
 
 On rocks. Winter. 
 
 " Forms a frustulose areolated- olive brown crust upon the wet per- 
 pendicular surface of limestone rocks, to which it adheres so slightly as 
 to be very readily detached. The plants are densely crowded in little 
 hemispherical masses, which, together, prodnoe the peculiar areolated 
 appearance of the crust. Each separate plant consists of a single fila- 
 ment at the base, which is from 1-4 or even more times tri- or tetra- 
 oholomouely branched, and thus a furtioose habit is given to the species. 
 Each branch has a connecting cell at its base, and sometimes one also at 
 about the middle of its length. The very thick cartilaginous sheaths are 
 of a pale brown colour towards the base of the plant but darker upwards, 
 except at the apices, which are frequently nearly colourless. The 
 endochrome is of a dull green colour, extremely narrow, and indistinctly 
 annulated ; towards the ends of the filaments, however, it becomes 
 much wider and slightly moniliform." 
 
 There is in the Kew Herbarium {Heri. SooTcerianum) a specimen of 
 Scytonema crustaceum , Ag., received from that authority himself — the 
 name written by him, which is clearly identical with Thwaites's plant, but 
 it could not consistently be united either with Scytonema or Stigonema, 
 hence we have retained the name applied to it by Thwaites and placed 
 it here, sabject to further investigation, its immediate allies being at 
 present doubtful. 
 
 Plate CXI 1. Jig. 2. Petronema fruticidosum after Thwaites; fig. 3, 
 Scytonema orustaeeum X 400, from authentic specimen received from 
 Agardh. 
 
 Sub-Tkibb II. TRICHOFKOREJE. Filaments tapering at the top 
 into a hyaline liair. 
 
 Family IV. CALOTRIOHB^. 
 
 Filaments free, or agglutinated into a definite thallus, ter- 
 minating at the apex in a delicate hair-like extremity. Hetero- 
 cysts normally present, scattered, or basal. 
 
 Genus 113. CALOTKRIX. Ag. (1824.) 
 
 Trichomes rather rigid, straight, attached, often fasciculate ; 
 growing in small tufts, or forming a turf of indefinite extent. 
 
276 NEMATOGEN^. 
 
 Calothzix Ozsiniana. Thm: Ann. Sex. Nat. 
 
 Forming a pulvinate stratum, as mucli as two lines in thick- 
 ness, dark brown, lubricous, opaque ; trichomes elongated, 
 branched, of nearly equal thickness, cuspidate at the apex or 
 obtuse, distinctly articulate, here and there moniliform ; sheaths 
 thick, lamellose, golden brown, from the base to above the 
 middle even, apical portion more or less dividing in fibrous 
 lamellae. 
 
 Size. Trichomes with sheatli ■01-'012 mm., without sheath 
 •0O4r-006 mm. 
 
 Kirch. Alg. SchJes., p. 219. 
 
 Scytonoma cirrhosum, Berk. Eng. Bot. ii., t. 2920. 
 
 Ccenocoleus cirrhosus, Berk. Eng. Bot. ii., sub. t. 2940. 
 
 Schizostphon cataractce. Nag. in Kutz. Tab. Phyc. ii., t. 52, 
 f. 1. Eab. Alg. Eur. ii., 235. 
 
 On rocks and submerged stones. 
 
 AlthoTigh "we have seen no anthentic Bpecimen of Berkeley's Ctsnoco- 
 leus, the specimens from Ben Lawers, which we have referred as above, 
 appear to us to belong to the same species, as far as can be judged in the 
 absence of all measarement. 
 
 Plate CXIII. fig. 1. Portion of trichome X 400; S, small fragment 
 magnified with sheath from Eng. Bot. t. 2920 ; c, cells of trichome free 
 from the sheath. 
 
 Calothziz Dill'wyni. {Sqss. Alg.) 
 
 Flaccid, bluish green or brown, trichomes usually cohering in 
 pairs, sheaths inconspicuous, except towards the base, joints 
 about half as long as their diameter, heterocjsts at the base of 
 the branches ovate or cordate. 
 
 Size. Trichomes ■005-"006 mm., with sheaths ■008-"01 mm. 
 
 Desmonema Dillwynii, Berk. Eng. Bot. ii., Supp., t. 2958. 
 
 Tolypothrix Dilhvyni, Hass. Alg. 242, t. 68, f. 4-5. 
 
 Microcoleus Dilhvyni, Harv. Man. 169. 
 
 Conferva vaginata, Dillw. Conf., t. 99. 
 
 On mosses and moist rocks. 
 
 Plant minnte, flaccid, mnch branched, seldom a quarter of an inch in 
 length, varying in coJoor from brown to bluishr green. Filaments 
 usually cohering in pairs. Sheaths inconspicuous, except those of the 
 older filaments at the base of the plant, whichbecome thickened and of 
 a reddish brown colour. Endochrome annulated, more evidently so in 
 the recently formed filaments than at the base of the plant, dotted from 
 the preaeuce of minute granules; joints about twice as broad as long, 
 the terminal one somewhat dilated and hemispherical. The branches 
 towards the base of the plant are seated each upon a connecting cell 
 (heterocyst) of an ovate or cordate form_ The plant possesses other 
 branches formed by a dislocation of the endochrome, each separated 
 portion becoming elongated, the lower portion towEirds the apex of the 
 
CALOTRIOHBiE. 277 
 
 plant, and the upper portion towards the base, and each parallel and 
 coherent with the other, and not usually separating until another dislo- 
 cation has taken place in the endoohrome of one of them, so that the 
 filaments cohere naostly in pairs throughout the plant, though some- 
 times four or more filaments are coherent within one common sheath. 
 The apparent branch (which is really a portion of the original filament) 
 always extends beyond the filament from which it appears to be 
 given off." 
 
 The dried specimens, which alone we have seen, are insufBcient to 
 determine the true relationship of this plant, hence, as well as the next, 
 their position must be accepted as provisional. 
 
 Plate OXIII. Jiff. 2. a, natural size ; b, portion enlarged; c, d, e, 
 trichomes X 400 diam. ; o and d, after Berkeley. 
 
 Species uncertain. 
 Calothzix (?) Smithii. (Be/'A. in, Eng. Boi.) 
 
 Filaments red, creeping, branched, contained, with their 
 ramifications, within a tongh, more or less permanent sheath, 
 which bursts irregularly, endochrome anniilated, very slender, 
 green, joints about as broad as long. 
 
 Size. Not stated. 
 
 Ccenocoleus Smithii, Berk. Eng. Bot. t. 2940. 
 
 On moors. 
 
 " Forming a red rugose mat of interlacing threads on boggy soil, 
 where it is very conspicuous, but from which it is separated with difii- 
 oulty on account of the roots and fibres of heath and moss to which it 
 adheres. 
 
 •'Threads elongated, branched laterally and acutely, their outer coat 
 being cartilaginous, within which fresh branches are generated and creep 
 within it till it is ruptured, when their free apices repeat the same 
 phenomena. Occasionally some of the ramuli burst through the sheath 
 at the base in pairs, as in genuine Scytonemata. Endochrome very 
 slender, green, the articulations about as broad as long." — M. J. B. 
 
 Genus 114. RIVULARIA. JJott. (1824.) 
 
 Frond having a tendency to an hemisphserical or bladdery 
 form. Filaments agglutinated by a more or less firm mucilage, 
 exhibiting a disposition to radiate from the base of the frond. 
 Frond usually with a well-defined outline. Heterocysts basal 
 (placed at the base of the principal filaments and branchlets). 
 Ramifications produced by the transverse division of the 
 trichomes, the upper part of which detaches itself and becomes 
 a lateral branchlet, while the lower part, extending itself by the 
 side of the old tip, makes a new extremity similar to the first. 
 Trichomes never producing any spores. 
 
278 NEMATOGEN^. 
 
 Rivnlaria ecUnata. (Bnglish Botany.) 
 
 Globose, very minute, dark coloured, compact. Threads 
 fastigiate, attenuated upwards to the apex, closely cohering, 
 articulated, heterocysts basal, globose. Sheaths very narrow, 
 almost inconspicuous. 
 
 Size. Trichomas '007 mm. at base, "25 mm. long. 
 
 Chcetophora punctifoi-mis, Kutz. Tab. Phyc. iii., p. 4, t. 18, f. 
 2. Eabh. Alg. Eur. iii., 386. 
 
 Echinella artieulata, Eng. Fl. v., p. 398. Eng. Bot. ii., t. 
 2555. Harv. Man. 187. 
 
 Conferva echinata, Eng. Bot. i., t. 1378. 
 
 Conferva echinulata, Gray. Arr. i., 310. 
 
 In lakes, ponds, &c. • 
 
 This minnte species, which was first described and figured in " English 
 Botany," appears to have been nnknovrn on the Continent. We have 
 received it from several localities beside the original one of Ellesmere. 
 It is one of the Algse which are associated with the phenomenon called 
 " Breaking of the meres," thus alluded to by Professor Dickie in his 
 " Botanists' Guide '' (p. 310) : — " For some years excursions were made 
 with the students of my botanical class to a loch on the estate of Parkhill, 
 about four miles north-west from Aberdeen. The sheet of water in 
 question is about a quarter of a mile in its greatest length ; on almost all 
 sides it is surrounded by extensive deposits of peat, with the soluble 
 matter of which a great proportion of the water passing into the loch is 
 impregnated. The locality was generally visited in the beginning of 
 July ; nothing particular had ever been observed till the summer of 1846, 
 when^my attention was arrested by a peculiar appearance of the water, 
 especially near the edge, but extending also some distance into the loch. 
 Numerous minute bodies, with a spherical outline, and varying in size 
 from 1 24th to l-12th of an inch in diameter, were seen floating at different 
 depths, and giving the water a peculiar appearance. In some places 
 they were very densely congregated, especially in small creeks at the 
 edge of the loch. A quantity was collected by filtration through a piece 
 of cloth, and, on examination by the microscope, there could be no doubt 
 that the production was of a vegetable nature, and a species of Hitmlana; 
 one, however, unknown to me, and not agreeing with the description of 
 any species described in works to "which 1 had access. Specimens were 
 sent to the Rev. M. J. Berkeley ; he informed me that the plant belonged 
 to the genus mentioned, and stated it to be JRimdaria eckintdata, Eng. 
 Bot. Along with it, but in very small quantity, I also found another 
 plant, Trichormus flos-aqwE, Bory. 
 
 " In the first week of July, 1847, the same species were observed 
 similarly associated, but the Trichormus was now more plentiful, with- 
 out, however, any apparent corresponding diminution in the quantity of 
 the Rivulm-ia. 
 
 " In July, 1848, it was observed that the Hiitdaria was as rare as the 
 TrickorTnus had been in 1846 ; to the latter consequently the water of 
 the loch now owed its colom-, which was a very dull green ; the colour, 
 however, becomes brighter when the plant is dried. In neither of the 
 seasons mentioned was it in my power to make any observations on the 
 colour of the loch earlier or later than the date above mentioned, conse- 
 quently nothing can be added respecting the comparative development 
 
CALOTRICnEJS. 2? 9 
 
 of the two plants at other periods of the season. Other two loohs in the 
 vicinity did not contain the plants alluded to." 
 
 As these pages are being printed (July, 1884,) this alga has been sent 
 ns from a large pond between Haslemere and Farnbam, rendering the 
 water quite opaque, described as " like a mixture of pea soup and 
 water." See also Boruet and Flahault, " Sur da determination des 
 Rivulaires, &o.," in "Bulletin de la Societe Botanique de France," 
 t. xxxi., p. 76 (1884). 
 
 Plate CXIV.fig. 2. a, natural size ; b, cluster magnified ; c, trichomes 
 X 400 diam. 
 
 Rivulazia calcazea. Eng. Bot. il. ed., t. 1799. 
 
 Hemisphajrical, gregarious, confluent in a very liard mamil- 
 lose incrusting bine-green or brownish stratum, internally re- 
 peatedly zoned, zones of a darker green, trichomes rather thick, 
 pale blue green, slightly fiexuous, distinctly articulate, ending 
 at the apex in a colourless hyaline point ; sheaths narrow, 
 colourless or brownish at the base ; heterocysts globose, lower 
 joints of the trichomes equal in length to their diameter. 
 
 Size. Trichomes -006 mm. diam. 
 
 Eng. Fl. v., 392. Harv. Man. 150. 
 
 Ainactis calcarea, Kutz. Tab. Phyc. ii., t. 63, f. 11. 
 
 Lithonema calcarea, Hass. Alg. 265, t. 65, f. 2. 
 
 Zonotrichia calcarea, Rabh. Alg. Eur. ii., 213. 
 
 Linckia dura, a calcarea, Grev. Fl. Edin. 322. 
 
 On rocks and stones in streams. 
 
 Plate CKVI. fig. 3. n, section natural size ; b, portion with trichomea 
 X 400 diam. 
 
 Rivulaxia duza. Kutz. 
 
 About the size of a mustard seed, rather hard, dark bluish- 
 green, becoming brownish or brackish ; trichomes »rnginous, 
 variable in the same thallus, some thin and inarticulate, others 
 thicker, articulate and torulose, all with distinct sheaths, 
 lengthened at the apex into a colourless fiexuous inarticulated 
 thread ; lower joints as long as broad, or nearly so, upper ones 
 longer, all granulated ; sheath colourless, or yellowish ; hetero- 
 cysts rounded, oblong. 
 
 Size. Trichomes 'OOS-'OOQ mm. diam. at the base. 
 
 Limnactis dura, Kutz. Tab. Phyc. ii., t. 64, f. 1. Rabh. Alg. 
 Eur. ii., 211. 
 
 Rivularia radians, var. dura, Kirch. Alg. Schles. p. 223. 
 
 Attached to aquatic plants, especially Chara. 
 
 Plate CXY.fig. 2. a, natural site , h, section enlarged) c, trichomes 
 X 400 diam. 
 
280 NBMATOGENJ;. 
 
 RiTUlaiia granulifexa. Cafmichael MSS. 
 
 Frond large, conv^ex, becoming hollow underneath, fleshy, 
 lubricous, brownish olive, often including strong particles. 
 
 Size. Trichomes -006 mm. diam. at the base. 
 
 Harvey in Eng. Flor. t., 393. Har7. Man. 151. Hass. Alg. 
 363, t. 65, f. 1, 4. 
 
 On cliffs exposed to the trickling of water. 
 
 ** Fronds from a line to half an inch in diameter, often confluent, con- 
 vex, and at length concave underneath, fleshy, dusky olive-green, and 
 extremely slippery. Filaments rather thick, repeatedly dichotomous." 
 — Carm. 
 
 Plate CXV. fig. 1. Trichomes, from an original and authentic speci- 
 men, X 400 diam. 
 
 Uncertain Species. 
 
 Rivulaxia botxyoides. Carmichad MSS. 
 
 Fronds minute, aggregated, roundish, wrialded, ferruginous, 
 cartilaginous. Trichomes dichotomous. 
 Size. Not stated. 
 Harvey in Eng. Flor. v., 392. Harv. Man. 150. 
 
 In streamlets, attached to rocks and stones. 
 
 " Fronds about a line in diameter, hemisphserical, wrinkled and carti- 
 laginous, scattered, or rnnning together like a bunch of grapes. Tri. 
 chomes cohering firmly, obscurely striated, dichotomous. Colour when 
 fresh, black, on drying, darkly ferruginous." — Carm. 
 
 We have seen no specimen, and therefore can add nothing to the 
 above description. 
 
 Rivniazia Crustacea. Carmiekad MSS. 
 
 Crust very thin, widely spreading, filaments attenuated at the 
 base, fastigiately branched above the middle, olive green. 
 Harvey, Eng. Flora v., 393. Harv. Man. 151. 
 Lithonema crustaceum, Hass. Alg. 266, t. 65, f. 3. 
 
 On rocks exposed to the spray of cascades. 
 
 " Crust of no determinate extent, extremely, thin and slimy, black. 
 Filaments one-fourth of a line in length, attenuated at the base, fasti- 
 giately branched above the middle, of an olive-green colour." — Oirm. 
 
 Genus 115. ISACTIS. TJiur. (1875.) 
 
 Similar to Rivularia, from which it differs in the frond being 
 flattened, and in the filaments being erect and parallel, and not 
 radiating. 
 
CALOTEICHEiE. 281 
 
 Isactis plana. Thur. Notes Alg. ii., p. 165. 
 
 Frond crustaceous, plane, suborbioular or confluent, from 1 in. 
 to 2 feet, dull green, darker in the centre, lubricous, gelatinous. 
 Trichomes erect, parallel, sheaths hyaline. 
 
 Size. Trichomes -008 mm. diam. 
 
 Born, and Thur. Notes Algol, ii., p. 165, t. 40, figs. 1-4. 
 
 Rivularia plana, Harv. Man. 152. 
 
 Dasyactis plana, Kutz. Tab. Phyc. ii., t. 73, f. 1. 
 
 Mastigonema plana, Eab. Alg. Eur. ii., 226. 
 
 Parasitic on Enteromorpha and other Algae, chiefly in salt or 
 brackish water, or on rocks by the sea. 
 
 Chiefly marine, but rarely on Enteromorpha, in estuaries and brackish 
 ditches. ' 
 
 Plate CXlF.flg. X. Trichomes x 350 diam.— after Boruet and Thuret. 
 
 Genus 116. GI.OIOTRICHIA. Ag. (1842.) 
 Trichomes pseudo-ramose, distinctly vaginate, sheaths broad, 
 often saccate at the base, transversely plicate. Spores originat- 
 ing in the lower part of the trichome. 
 
 Gloiotzichia natans. Thur. Ann. Sci. Nat. 175, 377. 
 
 Globose or angular, tuberculose, variable in size and form, 
 green, becoming brownish, trichomes straight, torulose, flexuous 
 and hyaline above ;" lower joints more or less compressed. Sheath 
 broad, here and there constricted, colourless or yellowish. Spores 
 oblong, cylindrical, heterocysts subglobose. 
 
 Size. Trichomes ■01--12 mm. at base, with sheath ; -03 mm. 
 diam. Spores -018 mm., and upwards, diam., several times 
 as long. 
 
 Bivularia gigantea, Fischer Nost., fig. 6. 
 
 Rivularia angulosa, Kutz. Tab. Phyc. ii., t. 67, f. 2, Eng. 
 Bot. t. 2551. Hass. Alg. 264, t. 60, f. 1-4. Eng. Fl. v., 394. 
 Harv. Man. 153. 
 
 Gloiotrichia angulosa, J. Ag. Alg. Med. 8. Rabh. Alg. Eur. 
 i., 201. Jenner, Tunb. Wells, 190. 
 
 Gloiotrichia Boryana, Kutz. Tab. Phyc. ii., t. 68, f. 2. Rabh. 
 Alg. Eur. i., 201. Ralfs. Alg. Exs., 21. 
 
 Gloiotrichia gigantea, Rabh. Alg. Eur. ii., 201. 
 
 Rivularia pruniformis, Purt. Midi. Fl. ii., 617. 
 
 Bivularia natans, Gray Arr. i., 285. 
 
 Tremella utriculata, Huds. Ang. 564. 
 
 In ditches, ponds, &c. 
 
 Plate CXVl. fig. 1. Trichomes x 400 diam. a, homogones of same 
 X 400 diam. 
 
 2 R 
 
282 NEMATOaEKE^. 
 
 Gloiotiichia pisum. TAur. Ann.dei Sei. J!fat.lS75,3n. 
 
 Of the size and form of a pea, sometimes as large as a cherry, 
 soft, even, or a little warted, dark olive-green, or brownish, tri- 
 chomes elongated ; the lower part blue-green, distinctly articu- 
 lated, the upper part setiform, colourless, and indistinctly arti- 
 culated, lower joints about equal in length and breadth, here 
 and there somewhat swollen ; heterocysts globose or subglobose. 
 
 Size. Trichomes •01--012 mm. diam. at base. Spores -Ol- 
 ■012 mm. diam., of variable length. 
 
 Kirch. Alg. Schles. 222. 
 
 Rivularia pisum, Ag. Syst., p. 25. Eabh. Alg. Eur. i. 206. 
 Berk. Glean, t. 11, f. 2. Eng. Fl. v., 392. Harv. Man. 150. 
 Mack. Hib. 235. 
 
 Linhia dura, Grev. El. Ed; 322. Johnst. Fl. Berw. ii., 261. 
 
 Physactis pisum, Kntz. Tab. Phyc. ii., t. 60, f. 3. 
 
 In ponds, ditches, &c., adhering to aquatic plants. 
 
 Plate XC7I. fig. 2. a, plants natural size ; b, trichomes of the same 
 X 400 diam. 
 
 Class III. RHODOPHYCEiE (or FLORioEiE). 
 
 Multicellular Algie, with terminal vegetation. Thallus com- 
 posed of a series of cells, either singly or disposed in strata, 
 which are naked or corticate, of variable form, membranaceous, 
 crustaceous, filamentose, vertically branched, fasciculate, folia- 
 ceous, &c. Cell contents for the most part reddish, rarely 
 otherwise coloured. Reproductive organs of three kinds, very 
 often disposed in different plants, viz. (1) Male organs, or an- 
 theridia ; (2), Female organs, orcystocarps ; and (3), Tetra- 
 sporangia. 
 
 For the most part marine. 
 
 Family I. PORPHYRACEiE. 
 
 Thallus mncous-membranaceous, foliaceons or filamentose, 
 formed from a single stratum of cells, chiefly purplish. Vege- 
 tation by division of cells in two or more directions. Propaga- 
 tion by tetraspores. 
 
 Genus 117. BANGZA. Lyngb. (1819.) 
 Thallus filamentous, terete or flattened, nearly plane, simple 
 or branched, for the most part purplish, lubricose, formed from 
 a single series of cells. Cell membrane thick, colourless, some- 
 times lamellose. Multiplication by the repeated division of the 
 cell-contents in all directions. 
 
CHANTEANSIAOE^. 283 
 
 ° Bangia atzo-puzpnrea. {Dillio.) Ag. Byst. p. 76. 
 
 Forming lax purple tufts ; threads abbreviated, scarcely ex- 
 ceeding an inch long, simple, varying in thickness according to 
 age, joints nearly equal in length to their diameter, or one-third 
 as long, more or less constricted at the joints. 
 
 Size. Filaments •08--06 mm. diam. Cells "01 mm. long. 
 
 Eabh. Alg. Eur. i., 398. Eng. Bot. ii., t. 24J.3. 
 Conferva atro-purpurea, Dillw. Conf., t. 103. Eng. Bot. i., t. 
 2085. 
 
 Oirardia fusco-purpurea, /3. Gray Arr. i., 287. 
 
 Attached to wood and stones in streams. 
 
 In his most recent work Agardh advocates the removal of this genus 
 to the UlvacecB, on aooount of the absence of genuine tetraapores. 
 
 Plate CXVII. Jig. 1. a, portion of tuft, natural size^ J, portions of 
 threads X 400 diam. 
 
 Family II. CHANTRANSIACE^. 
 
 Forming dwarf pulvinate tufts, of a purplish-violet or steel- 
 blue colour. Thallus filamentous. Threads articulate, formed 
 of a single series of cells, branched, straight, naked, fasciculately 
 branched above, joints cylindrical. Propagation by immovable 
 spores formed at the tips of the branchlets. Tetraspores rarely 
 observed. 
 
 Genus 118. CKANTRANSIA. Friei. (1825.) 
 
 The only genus in the family, with the same characters as 
 given above. 
 
 Chantzansia violacea. KuU. Tab. Pliyo. v. #. 4i,/. 2. 
 
 Tufts bright violet, scarcely exceeding a line broad, pulvi- 
 nately rounde^, threads straight, branches becoming erect, 
 radiately disposed ; joints 3-6 times as long as broad, the apical 
 joints rather obtuse. 
 
 Size. Cells -OOS-'OOg mm. diam. 
 
 Eabh. Alg. Eur. iii,, 402. Kirch. Alg. Schles. 47. 
 Parasitic on Lemanea, Cladophora, and aquatic mosses. 
 
 Plate CXFlll. fig. 1. a, tuft natural size ; b, portions of filaments X 
 300 diam. 
 
284 RHODOPHYCEJS. 
 
 Chantransia Heimanni. {Rath^ KuU. Phyc. Germ. 230. 
 
 Caespitose, pale rosy-purple, three lines long ; threads and 
 branches whip-like, straight, branchlets spreading, then ascend- 
 ing, joints 3-6 times as long as broad, the final joints cuspidate, 
 or rarely piliferous. 
 
 Size. Cells •009--002 mm. diam. 
 
 Ealfs. Ann. Nat. Hist. 1851, p. 403. Eabh. Alg. Eur. iii., 
 402. Kirch. Alg. Schles. 46. Kutz. Tab. Phyc. v., 43, f. 2. 
 
 Trentepohlia pulchella (Ag.) Eng. Fl. v., 382. Eng. Bot. ii.. 
 t. 2533. Harv. Man. p. 118. Johnst. Fl. Ben?, ii., 242. 
 Mack. Hib. 219. 
 
 Conferva nana, Dillw. Conf. t. 30. Gray Arr. i., 308. Eng. 
 Bot. i., t. 2585. 
 
 On aquatic plants in streams. 
 
 " The tnf ts are dense, soft, and woolly, not gelatinons. and adhere hnt 
 imperfectly to paper ; they are often confluent, their colour is reddish, 
 becoming tawny by age, and in drying. Filaments much branched, main 
 branches elongated, somewhat level-topped, fructiferous branches latei'al, 
 numerous, short,'patent, much divided. Capsules at first oval or clavate, 
 finally orbicular, crowded in a corymbose manner, mostly stalked. 
 Joints of stem 3-5 times as long as broad, those of fertile branches 
 shorter. Differs from C. chalyhea in colour, and in its shorter joints and 
 more patent ramnli." — Salfs. 
 
 Plate CXriII. fiff. 2. Portion of filament X 30O diam. 
 
 Chantxansia chalybea. (Li/ngi.) Evis. Pkyo. Gen. 229. 
 
 CsBspitose, steel-blue, about an inch long. Threads radiately 
 disposed, adpressed, branches straight, joints three to six times 
 as long as broad, spores collected in a racemose manner on lateral 
 branchlets. 
 
 Size. Cells ■01--011 mm. diam. 
 
 Ralfs. Ann. Nat. Hist. 1851, p. 304. Brit. Algae Exs. No. 
 11. Rabh. Alg. Eur. iii., 402. 
 
 Conferva chalybea, JHWyi. Conf. t. 91. 
 
 Conferva corymbosa, Eng. Bot. i., t. 1666, f. 1. 
 
 Trentepohlia coi-ymhifera, Eng. Bot. ii., t. 2534. 
 
 Trentepohlia pulchella, (i, chalybea, Eng. Fl. v., 382. Harv. 
 Man. 118. Mac. Hib. 219. 
 
 Trentepohlia chalybea, Johnst. Fl. Berw. ii., 243. 
 
 Ectocaipus chalybeus. Gray Arr. i., 322. 
 
 Trentepohlia pulchella, Hass. Alg. 73, t. 8, f. 2. 
 
 Rivulets, waterfalls, and on water-wheels. 
 
 " Plant laxly tufted, of an inky colour, more or less tinged with green. 
 Branches rather distant, level-topped, erect, their joints 4-6 times longer 
 than broad. Fertile branches short, appressed, their joints shorter and 
 usually turgid. Capsules orbicular, corymbose." — Ralfs. 
 
 Plate CXIX. fig. 3. a, portion of tnft natural size j 'h, portions of 
 threads X 30O. 
 
CHANTEANStAOfi^. 285 
 
 Chantzansia pygmsa. Kutz. Phy. Gen. 285. 
 
 Tufts rounded, about a line in diameter, dingy greenish, be- 
 coming reddish, violet, or steel-blue when dry ; threads proceed- 
 ing from a common centre, branched upwards in a somewhat 
 fasciculate manner, branches erect, parallel, rather adpressed ; 
 joints 2-3 times as long as broad, apical joints obtuse ; fascicles 
 lateral or terminal. 
 
 Size. Cells •011-'014 mm. diam. 
 
 Eabh. Alg. Eur. iii., 403. Kirch. Alg. Schles. 47. Kutz. 
 Tab. Phyc. v., t. 45, f. 2. 
 
 In streams and springs. 
 
 Plate CXIX. fig. 2. a, tufts natural size ; i, portions of filaments X 
 300 diam. 
 
 Chantxansia investiens. Lenormand in Kutz, Sp, 431. 
 
 Parasitic, rose-red, much branched, joints many times longer 
 than broad, spores solitary or in pairs, lateral and terminal, 
 clavate or obovate. 
 
 Size. Cells -006 mm. diam. 
 
 Ealfs. Ann. Nat. Hist. 1851, p. 303. Ealfs. Brit. Alg. Exs. 
 No. 12. Kutz. Tab. Phyc. v., t. 45, f. 4. 
 
 Batrackospei-mum rubrum, Hass. Alg. 113, t. 15, f, 2-3. 
 
 On Batrachospermum moniliforme and B. atrum. 
 
 " Plant bright red, at first appearing as a minute reddish stain, finally 
 clothing the invested plant with a continuous downy covering. Fila- 
 ments creeping and interlacing at base, and surrounding the plant on 
 which it grows, much branched. Branches not attenuated, alternate, 
 erect, elongated ; joints very long, often twelve times as long as broad, 
 and filled with pink, slightly granular endoohrome. Capsules clavate or 
 obovate, alternate or opposite, sometimes, though rarely, opposite a 
 branch ; the terminal ones are more orbicular." — Malfs. 
 
 Plate CXIX. Jig. 1. Portions of filaments X 300 diam. 
 
 Uncertain Species. 
 
 Chantzansia scotica. KuU. Tab. Phyc. v. t. 42. 
 
 Csespitose, about an inch long, steel blue ; threads sparingly 
 branched, branches rather elongated, and, as well as the 
 branches, somewhat divergent ; joints 2-3 times as long as 
 broad. 
 
 Size. Cells about ■009-'01 mm. diam. 
 
 Eabh. Alg. Eur. iii. 402. 
 
 On old immersed wood. 
 
 We have no knowledge of this species. The figure is reproduced from 
 that of Kutzing. 
 
 Plate GXVIh fig. 2. Portion of thread X 300 diam. After Kutzing. 
 
286 RHODOPHTCE^. 
 
 Chanttansia compacta. Rolfs. Awn. Nat. Bist. 1851, p. 304. 
 
 Plant minute, hemispherical, inky-green, firm ; filaments 
 much branched, joints twice as long as broad, branches erecto- 
 patent. 
 
 Size. Not stated. 
 
 On aquatic plants. 
 
 " It forma very minute hemispherical tufts or fronds of a dark oolonr, 
 and very much resembles a EiTularia in appearance ; the fronds are so 
 firm as to require considerable pressure in order to separate the fila- 
 ments for microscopic examination. Filaments comparatively stout, 
 rigid, much branched at the base, horizontal and interlacing. Branches 
 crowded, ereoto-patent ; joints about twice as long as broad, but the 
 lower ones frequently shorter. Capsules orbicular, numerous, lateral, 
 arising from all parts of the plant, and usually on short stalks. Differs 
 from C. chalyhea in its compact, firm habit ; more crowded branches, 
 shorter joints and more scattered capsules." — Ralfs. 
 
 Probably this is C. pygmcea, but we have seen no specimen. 
 
 Family III— BATRACHOSPERMB^. 
 
 Dioecious algse. Thallus filamentous, articulate, branched, 
 violet, or violet-purple or bluish-green, covered with mucous ; 
 primary filament and branches composed of a single central 
 series of cells, and numerous external parallel continuous or in- 
 terrupted secondary series ; either furnished with globosely or 
 subglobosely densely conglobate tufts, of equally distant verti- 
 cillate fascicles of branches, or everywhere densely covered with 
 simple or forked branches. Vegetation terminal. 
 
 Genus. 119. BATRACHOSPERMUM. Roth. (1800.) 
 Thallus moniliform, composed of a simple series of medullary 
 cells, and a cortical accessory parallel series, clothed with sub- 
 globosely clustered fascicles of branches, which latter are some- 
 times more or less dispersed. 
 
 Professor Horatio Wood has abstracted so well what is tnown of the 
 reproductive process in the Batrachosperms that we cannot do better 
 than quote his observations in full : " Frequently in well-advanced 
 Batrachosperms there will be seen scattered among the glomerules large 
 round, firm, dense balls, composed of a great number of small closely 
 attached cells. These are the reproductive bodies. According to Graf 
 ru Solms Laubach ("Botanische Zeitung," 1867, p. 161), they are the 
 result of sexual reproduction, and are developed from ' antheridia ' and 
 ' trichogonia' (female organs) in the following manner : — 
 
 " The antheridia are small roundish cells full of a colourless proto- 
 plasm, which is remarkable for the very numerous bright granules which 
 it contains. They cccnr either scattered, or in groups, and are placed 
 
BATRACHOSPEEMB^. 287 
 
 upon the npper ends of peculiar ovate cells, also filled with a colourless 
 protoplasm. Most frequently there is a single antheridinm to the basal 
 cell, sometimes two ; the latter number appears never to be exceeded. 
 When matured the autheridia open, and allow their contents to escape in 
 the form of roundish or flattened bodies, which never, as far as known, 
 acquire cilia, and have, therefore, no power of spontaneous motion. 
 These bodies, which are believed to be spermatozoids, are unprovided 
 with anything like an external membrane, and are composed of proto- 
 plasm identical with that in the antheridium. While these changes are 
 occurring, certain cells in other localities are being traasformed into 
 female organs, to which the name of Trichogonia is applied. These are 
 borne upon cells similar to those supporting the antheridia. At first they 
 are not markedly different from the other cells, but soon undergo a very 
 rapid growth. This is not, however, regular, and is not partaken of by 
 a band of tissue about one-third way from the basal end, so that at last 
 a long somewhat flask-shaped cell is produced, with a very marked con. 
 traction at the point indicated, separating it into two portions. The 
 wall of this cell is thin, but very distinct, and the cavity is filled with a 
 homogeneous or very sparsely granular protoplasm, which is continuous 
 through the narrow neck-like portion. After a time there appear one or 
 more large irregular vacuoles, with actively moving corpuscles in 
 them, and at the same time the neck appears to be stopped with a slimy 
 substance. Careful examination with reagents shows that this is a cel- 
 lulose, and that it does not completely block the passage way through 
 the isthmus. At this time there appear lying upon the free end of the 
 trichogonia globular or flattened bodies, without external membrane, 
 corresponding in all respects with those already described as being pro. 
 duced in the antheridia. The end of the trichogonium generally enlarges 
 at this period^into a sort of roundish knob, and by and bye the end wall 
 between this and one of these globules becomes absorbed, so that there 
 is a free communication between the two. Whilst this is 'going on the 
 globule acquires a thin delicate odat, and there ; appears in it a vacuole 
 similar to those pre-existing in the trichogonium. 
 
 " The first result of this impregnation of the trichogonium is the de. 
 posit of new cellulose, and the complete blocking up of the passage way 
 through the isthmus or narrowed portion. Already before the fecunda- 
 tion the upper cells of the branches supporting the trichogonia have pro- 
 duced numerous branchlets, which, growing upwards, more or less com- 
 pletely cover that organ. After impregnation the cells near to the 
 trichogonium become much larger and broader, their vacuoles disappear, 
 and are replaced by a dense granular dark greenish-brown protoplasm. 
 
 These cells now show a great activity in the production of numerous 
 branches in the usual way ; but it is the upper two alone which, with the 
 trichogonium that they support, are concerned in the formation of the 
 fruit glomerules. These put out all over their surface an immense num. 
 ber of protrusions, which soon, in the ordinary way, become the parents 
 of as many twigs or branchlets, which, growing and branching precisely 
 as do the vegetative branches, soon become excessively crowded. The 
 base of the trichogonium participates also in the production of branches, 
 and at last a dense ball is formed of pseudo-parenchymatous tissue by 
 the forced adhesion of the crowded twigs. The central cells of the 
 glomernle thus formed are very large and bladder-like; The outer part 
 of the ball is composed of innumerable radiating rows of small cells, the 
 end cell of each branch being roundish so as to present a convex external 
 face. 
 
 " At maturity these cells open and allow their contents to escape as 
 round masses, which appear to have no membrane, but begin at once to 
 grow and secrete cellulose. Their after history has not been made out 
 
288 RHODOPHTCE^. 
 
 with abgolnte certainty, but they are believed to directly develop the new 
 p\a,Dt."~Wood's Iresh Water A'ffm nf U.S., p. 218. 
 
 It is somewhat uncertain what should constitute the limits of species 
 in this genus, so that, with the exception of I^. atrum, we have not de- 
 parted from the most generally accepted series, although we fail to dis- 
 tinguish more decided specific characters to separate B. vagum from B. 
 monUiforme than can be found between, so-called, varteties of these 
 species. 
 
 Batxacbospetmam monilifoime. Both. Cat. Bat. in., 160. 
 
 From one inch to a foot in length, clothed with a more or less 
 firm gfilatinous mucous, violet-broivnish, reddish-brown, purple, 
 or bluish-green, vaguely and profusely branched, joints of the 
 branches similar, oblong or clavate, outer ones sometimes seti- 
 gerous, internodes naked, or furnished with scattered accessory 
 branches. 
 
 Size. Cellules -02-022 x -01 mm. 
 
 Eabh. Alg. Eur. iii., 405. Kirch. Alg. Schles. 45. Eng. Fl. 
 V. 388. Jenner, Tunb. "Wells, 176. Eng. Bot. ii., t. 2542. 
 Harv. Man. 119. Johust. Fl. Berw. ii., 257. Mack. Hib. 221. 
 Hass. Alg. p. 109. Hook. Fl. Scot, ii., 77. Gray Arr. i., 330. 
 Vauch. Conf. 112, 1. 1, f. 5 ; t. xi, f. 4. 
 
 Conferva gelatinosa, Dillw. Conf. t. 32. Eelh. Cant. Supp. 
 21. Hull Br. Fl. 332. Eng. Bot. i., t. 689. Huds. Ang. ii., 
 597. With. Arr. iv., 134. Lightf. Fl. Scot. 986. Sibth. Ox. 
 337. Abbot. Bedf. 275. 
 
 Conferva fontana nodosa spermatis ranarum, Ray Syn. 62. 
 Dill. Muse. 36, t. 7, f. 42-46. 
 
 Batrachosperma ludibundamomlifomia,^OTj. Ann. des Mus. 
 XX., t. 30, f. 1. 
 
 In streams and ditches. 
 
 Plate CXX. fig. a, portion of filament X 30 diam. ; J>, portion X 20O 
 diam. 
 
 var. setigerum. Babh,. Algee Exs. No. 854. 
 
 The extremities of the moniliform branchlets attenuated into 
 a long setiform thread. 
 
 Size. Cells -02 --024 x 'Ol mm. 
 
 var. pulcherximiun. Bory. Ann. des. Mus. p. 40. 
 
 About four inches long, violet or purple, the gelatinous in- 
 vestment less developed. Branches elongated, whorls rather 
 distant, globose, with the apices of the branchlets almost con- 
 fluent, interstitial spaces nearly naked. 
 
 Size. Cellules -018 x •01--012 mm. 
 
 Kirch. Alg. Schles, 45. Eabh. Alg. Eur. iii., 405. 
 
 Batrachospermum pulcherrimum, Hass. Alg. 109, t. 14, f. 1. 
 
 Batrachosperma ludibunda pulcherrima, Bory. loc . cit. 
 
BATBACHOSPEEME^. 289 
 
 " The extreme elegance of form and of colour renders this Batracho- 
 spermum remarkable j its stems are rather more branched than those of 
 the variety confusumj and less than those of B, moniliforme, are from 2 
 to 3| inches long, slender, and of an intermediate diameter. The globules 
 are perfectly spherical, distant upon the stems from each other the 
 length of a ray, more approximate, flattened, but always distinct in the 
 branches. Its colour is a clear grey, approaching to a most agreeable 
 violet ; this last tint becomes dominant in drying, and passes sometimes 
 to TeH."- -Hassall. 
 
 Plate CXXI.jig. a, portion of filament X 30 ; fig. J, smaller portion 
 X 200. 
 
 var. pzolifexum. KuH. 
 
 Stem and primary branches densely set with short accessory 
 branchlets. 
 
 Size. Cellules -018 X "01 mm. diam. 
 
 Eabh. Alg. Eur. iii., 406. 
 
 Batrachospermum proliferum, Hass. Alg. 112, t. 63, f. 1. 
 
 B. moniliforme, /3 proliferum, Carm. MS8. 
 
 " Frond solitary, or in small clusters, 1 or 2 inches long, irregularly 
 branched, branches divaricate, curved, or flexuous, opaque, and very 
 dark coloured, beset with short ramnli, which issue out from the joints 
 among the whorls, of eccentric filaments, and are themselves beset with 
 whorls. Colour grey. — Carmichael. 
 
 Flate CXXII. Portion of filament X 200 diam., from original speci- 
 men. 
 
 var. confusum. Sass. Alg. 105, 1. 15, /. 1. 
 
 For the most part bright violet, 2-3-4 inches long, and simi- 
 larly expanded, densely involved in a gelatinous mucous, whorls 
 approximate, with numerous interstitial ramuli irregularly dis- 
 posed. 
 
 Size. Cellules •02--022 x -01 mm. 
 
 Eabh. Alg. iii., 405. Kirchn. Alg. Schles, 45. 
 
 Batrachospermum confvsum, Hass Alg. 105. 
 
 Batrachospermum giganteum, Kutz. Tab. Phyc. iii., t. 28. 
 
 Batrachospei'ma ludihunda confusa, Bory. Ann. des Mus. xx., 
 t. 29, f. 3. 
 
 " Of all Batrachosperms this acquires the greatest dimensions. Its 
 length is sometimes four inches and a half, its diameter equal often to 
 that of the culms of grasses. Its branches appear also to be less obtuse 
 than in the other varieties. The globules, or whorls, are so approximated 
 and so large that they are often confounded together in such a manner 
 as to be with difficulty distinguished in certain specimens which have the 
 aspect of B. Jielmintosum. The colour of the plant is of a mouse-grey, 
 agreeable by its transparency. The large stems approach a little upon 
 yellow. These tints become of a beautiful violet by putrefaction. It is 
 upon individuals of this variety that I made for the first time, twelve 
 years ago, an experiment which ought to be known ; after having many 
 
 2 S 
 
290 
 
 RHODOPHYCB^. 
 
 times carried from one locality to another stones bearing individnals of 
 this species, which continned to prosper in spite of the change of habita- 
 tion, I steeped many of them in lukewarm water, afterwards in boiling, 
 and no part of the Batrachosperm appeared, nnder the microscope, 
 to have undergone the slightest disorganization by these immersions, 
 and certain sprigs, replaced in their native place, continued to vegetate 
 after these experiments. I do not think that there exist other vegetables 
 which boiling water does not immediately disorganize, there are not 
 others that can resist temperatnres so opposite." — Bory. 
 
 Plate CXXIII. Portion of filament X 200 diam. 
 
 va/r. Boltoni. Cooke. 
 
 This variety differs in the large size and very globose form 
 of the joints of the vrhorls. The apices are very often setiform. 
 Size. Cellules -025 x "02, or -022 x -018 mm. 
 
 This variety, found by IJr Thomas Bolton, of Birmingham, seems to 
 differ sufBciently to be worthy of notice as a distinct variety. In colour 
 it was a beautiful green, with a tendency to pass into blue in drying. 
 
 Plate CXXIV. Portions of a filament X 200 diam. 
 
 var. stagnale. Ag. 
 
 One or two inches long, blue or steel-blne. Whorls of the 
 stem confluent, of the branches distant. 
 
 Rabh. Alg. Eur. iii., 406. 
 
 Batrachosperma ludibunda stagnalis, Bory. Ann. Mas. xx., 
 p. 42. 
 
 Batrachospermum stagnale, Hass. Alg. p 107. 
 
 Conferva fontana nodosa, &c., Dill. Muse. f. 44. 
 
 " This variety has great resemblance in form and diameter to con- 
 fiiS7im ; it is nevertheless shorter, but as thick. Its whorls are round 
 and distinct ; they are more approximated the one to the other in the large 
 stems, about which they are sonietimes even confused. Their colour is 
 a greenish-yellow, pale and livid." — Hassall. 
 
 var. alpestze. ShuttUmoHli. 
 
 Frond black, very mucous, much branched, alternately form- 
 ing very obtuse angles with the principal filaments . Whorls of 
 the stem spherical, distinct, but approximate, branches com- 
 pressed. 
 
 Batrachospermum alpestre, Hass. Alg. Ill, t. 14, f. 2. 
 
 " This species is easily recognized by the eye alone, either in its recent 
 or dried state ; in the former its size, great lubricity, jetty black colour, 
 and approximate, yet for the most part, exactly sphserical whorls, are 
 remarkable ; in the latter, in which also the black tint is preserved, it 
 may be distinguished by the multiplicity of its branches, which are, 
 except the primary ones, exceedingly short and irregular, and issue from 
 the main filaments almost at right angles, and by their non-moniliform 
 appearance. In drying, also, it shrinks considerably." — Sassall. 
 
BATKACHOSPEEMEiE. 291 
 
 var. helmintosum. Boiy Ann. d. Mus. t. 29, f. 2. 
 
 Filaments branched, pyramidal, naked below, branches simple, 
 subpinnate, acute whorls contiguous, compressed. 
 
 Batrachosperma helmintosa, Boij Ann. Mus. xx. p. 33. 
 Batrachospeiinum helmintosum, Hass. Alg. p. 105. 
 
 " The stems of this beautiful species scarcely exceed 2 inches in length. 
 They are fine, and denuded at their base, which appears yellow. 
 Numerous branches proceed from it ; they are somewhat subulate, and 
 diminish in length in such a way that they incline from the extremities 
 of the plant, and give it a pyramidal appearance. The whorls are com- 
 pressed, voluminous, horizontal, and so approximated that they cannot 
 acquire the globular form ; they become confused, and form round the 
 stems a continuous cylinder of mucosity. The diameter of this cylinder 
 equals often that of the plume of a little bird. The branches are not less 
 thick at their insertion. The colour of the plant is obscure, of a bluish 
 and uncertain green." — Bory. 
 
 var. bambusinum, Bory. Ann. d. Mus. i. 29, /. 1. 
 
 Filaments sparingly branched, branches simple, cells much 
 elongated, whorls minute, distant. 
 
 Batrachosperma bamhusina, Bory Ann. Mus. xx. p. 32. 
 
 Batrachospeiinum bombusinum (Bory). Hass. Alg. 103, t. 
 13, f. 3. 
 
 " Its colour is of the most elegant green ; but if the specimens be not 
 quickly prepared they very soon turn black upon the paper. Prom a 
 principal filament, 2-4 inches long, proceed many long, slender, loose 
 branches, simple, or having sometimes here and there scattered, very 
 small branches, which are never divided. The articulations of the 
 principal stem, and of the larger branches, are for the most part naked ; 
 their point of contact is dilated in such a manner as to resemble the rods 
 of bamboos. As to the whorls, they are rounded, smaller than those of 
 the neighbouring species, composed- of very compact branchlets. Their 
 simple ramuli are likewise shorter than in the other Batrachosperms ; 
 three or four ronnded joints compose them ; the ciliform appendage 
 which terminates them is remarkable. Some ramuli, shorter than those 
 of the whorl, cover also the inferior part of the articulations, which have 
 the appearance of reversed cones." — Bory, 
 
 Batrachospezmum vagum. (Both.') Ag. Syst. 52, 
 
 Vaguely branched, 1-3 inches long, brownish or bluish-green ; 
 inferior internodes covered with a dense mass of branchlets, the 
 superior naked, or nearly so, apical joints of the branchlets 
 attenuated into- a long bristle. 
 
 Size. Cellules -025 x -012 mm. 
 
 Kabh. Alg. Eur. iii., 406. Kirch. Alg. Schles. 46. Eng. 
 Fl. v., 388. Eng. Bot. ii., 197. Harv. Man. 119. Hass. Alg. 
 109, t. 63, f. 2. Kutz. Spec. 536. 
 
 Batrachosperma turfosa, Bory Ann. des Mus. xx., t. 32, f. 1 , 
 
292 EHODOPHTCBJi:. 
 
 " In no other Conferva is the nnraber of the filaments so considerable 
 as this. Their total diameter equals that of the largest horsehair. They 
 divide in every direction from a little disc, ramify to infinity, observing 
 remarkably vrell the diphotomons disposition in their first division, their 
 branches becoming subsequently vague. Their total length extends even 
 to four inches. 
 
 " From their origin even to their extremity these filaments are clothed 
 with microscopic branches, so impacted that the whorls are not apparent 
 in scarcely any direction ; with a simple lens they are not better dis- 
 covered, from which it might be supposed that one was observing a 
 Thwea. It is but towards the points of the branches that, by the assist- 
 ance of a strong lens, they are at last distinguished. These whorls are 
 very closely approximated, horizontal, compressed the one upon the 
 other, and becoming so confused as to form around the filament, which 
 is green or yellow, and very fiexible, a continuons down, mucous to the 
 touch, sometimes very pale, more frequently of a very agreeable bluish 
 watery green ; this colour is, moreover, deep towards the point of the 
 branches. As it grows old the plant turns yellow, and is discoloured." — 
 Bo7-y. 
 
 var, kezatophytum. Sory. 
 
 Beautiful blue-green, thin, very much branched, dichotomous, 
 with the black setaceous base naked, branches all equal, slender, 
 thin, apex slightly incrassated, whorls distinct. 
 
 Size. Cellules clavate, about '03 x "015 mm. 
 
 Batrachospei-ma keratophyta, Bory Ann. Mus. xx., t. 31, f. 2. 
 
 Batrachospermum suevorum, Kntz. Spec. 536. 
 
 Habit, colour, and ramification of B. vagum, but with the whorls dis- 
 tinct. 
 
 Plate CXXV. fig. a, portion of filament X 30 ; b, portion X 200 
 diam. 
 
 Batzachospezmum atzum. Harv. Man. 119, 
 
 Violet-coloured when moist, dark brown, almost black when 
 dry, vaguely and much branched, reaching 2 inches, whorls 
 abbreviated, distant ; interstitial branchlets very short, one or 
 two-celled. 
 
 Size. Cellules '012 mm. diam. 
 
 Jenner Tunb. Wells 176. Hass. Alg. lU, t. 16, f. 4. 
 
 Conferva atra, Dillw. Conf. t. 11. Hull Br. Fl. 332. Huds. 
 Ang. ii., 597. Eng. Bot. i., t. 690. With. Arr. iv., 134. 
 Gray. Arr. i., 330. 
 
 Batraehospermum detersum, Eng. Bot. ii., t. 2543. 
 
 Batrachospermum moniliforvie, v. detersum, Eng. Fl. v., 388. 
 Mack. Hib. 221. 
 
 Batrachospermum moniliforme, var. i. ati-um, Eabh. Alg. Eur. 
 iii., 406. Kirch. Alg. Schles. 45. 
 
 Lemanea setacea, Bory Ann. de Mus. t. 23, f. 3. 
 
 In streams and ditches. 
 
 Plate CXXVI, fig. \. a,, portion of filament X 30 j b, portion X 200 
 diam. 
 
batrachospermb^. 293 
 
 " The artioulations, or internodes, may be compared to reversed cones, 
 the superior part or whorls being formed of a few short, simple eubn- 
 late filaments, which are not beaded ; in these filaments the colouring 
 matter chiefly resides, and it is amongst them that the glomeriiles are 
 formed ; that portion of each articulation which is below the whorl is 
 transparent, and beautifully exhibits the tubular and jointed structure 
 of the layers which inresk the primary cells in all the species of the 
 genus Batrachospermum ; from many of these tubes short branches are 
 given off, which have almost the appearance of scales." — Hassall. 
 
 var. Dillenii. Bory. Ann, de Mus. xx., i. 22, f. 2. 
 
 Filaments dark brown, very thin, lower nodes remote, the 
 interstices beset very densely with prominent cells, upper nodes 
 crowded, branchlets very short, consisting of 3-4 cellules, ex- 
 treme apical nodes confluent. 
 
 Size. Cellules "012 mm. diam. 
 
 Lemanea Dillenii, Bory. Ann. de Mus. xx., 23. 
 
 Baljrachospermim vagum, e. Dillenii, Eabh, Alg. Eur. iii., 
 407. 
 
 Conferva fontana nodosa, lubrica, nigris, Dill. Muse. t. 2, f. 
 46. 
 
 This is usually considered as a variety oC B. vagum-, but it seems more 
 closely allied to B. atrum, if that be really a distinct species. 
 
 Flate CXXVI. fig. 2. Portion of filament X 200 diam. 
 
 Genus 120. THOREA.. Bory. (1808.) 
 
 Thallus filamentose, attenuated at the apex, branched, purple- 
 brown, villose, mucous, with a solid central medullary stratum, 
 surrounded by dichotomously divided branchlets. — Surun genre 
 nouveau de la Cryptogamie aquatique, nomme Thorea. 
 
 Thozea xamosissima. Bory Ann. Mus. xx. 127. 
 
 From a hand's-breadtli to a foot long, and rarely two feet, 
 very much branched, about the thickness of a horsehair, dark- 
 green,- of a beautiful purple-violet when dry, ramelli spreading 
 horizontally, long and short alternating, articulate; joints 1-3 
 times as long as broad, or twice that length. 
 
 Harv. Man. 120. Hass. Alg. 65, t. 16, f. 3-4. Rabh. Alg. 
 Eur. iii. 
 
 Batrachospermum hispidum, De Cand. Fl. Fr. ii., 60. 
 
 Attached to wood, &c. Walton-on- Thames. 
 
 FlAte CXXVII. fig. a. Small plant, natural size j J, ramuli and spore j 
 C( portion of filament X 400. 
 
294 RHODOPHYCE^., 
 
 Family IY. LEMANBACE^. 
 
 Flnviatile algae. Thallus developed from a confervoid pro- 
 thallic filament, setaceous, almost simple, hollow, nodose, having 
 an internal and a cortical layer of cells. Polyspores numerous, 
 collected in branched moniliform series, germinating without 
 fertilization. 
 
 Gsmis 121. LEMANEA. Borif. (1808.) 
 
 The only genus in the family, with the same characters as above 
 given. 
 
 " The dilated portions of the threads are loosely filled with the spores, 
 which are produced within the frond. The spores are oval, thick-walled 
 cells, joined together to form series, which are very mnch branched, so 
 that from a central basal row ther rise as a complex bnsh-like mass. The 
 first step, according to Wartmann, in their germination, consist&in the 
 elongation of the spore, and the projection of one end, which is soon cut 
 off by the formation of a transverse partition, and constitutes a new cell. 
 This multiplication soon develops into a branched confervoid filament. A 
 large number of these filaments are generally produced in one place at 
 one time, and form a very apparent greenish layer. Finally, certain cells 
 in branches of these filaments swell up and become very much broader 
 than their fellows, undergoing, at the same time, division so rapidly that 
 they become very short. By-and-bye they divide also in the direction 
 of their breadth, so that, instead of a simple series of cells, there arises 
 a compound mass. This is the beginning of the new frond. At first it 
 is dependent upon the parent filament, but soon acquires a root-like pro- 
 cess at the base, and develops rapidly into the complex cartilaginoua 
 plant." — Wartmann, Beitrage zur Lemanea (1854). 
 
 Lemanea flUTiatilis. Ag, Spec. Alg, ii. p. ■i. 
 
 Simple, or sparingly branched, 3-4 inches long, straight, 
 nodules rather remote, with about three verticUlate papillae. 
 Size. Spores -04 x "025 mm. 
 
 Eabh. Alg. Eur. iii.,41]. Kirch. Alg. Schles. 43. Eng. Fl. v., 
 p. 322.- Hook. Fl. Scot, ii., 84. Eng. Bot. ii., t. 2423. Jenner 
 Tiinb. Wells 176. Harv. Man. 119. Johnst. Fl. Berw. ii., 
 246. Mack. Hib. 220. Gray Arr. i., 288. Hass. Alg. 72. 
 
 Lemanea cor allina, Bory Ann. de Mas. xx., t. 21, f. 2. 
 
 Conferva fluviatilis. Dill. Conf. t. 29. Hull Br. Fl. 332. 
 Eng. Bot. i., t. 1763. Huds. Ang. ii., 597. With. Arr. iv., 
 134. Lightf. Fl. Scot. 985. 
 
 Conferva fluriatilis lubrica setosa equiseti facie, Dill. Muse. 39, 
 t. 7, f. 47. 
 
 Nodularia fluviatilis, Grev. Fl. Ed. 300. Fl. Devon, ii., 57. 
 
 Attached to stones, wood, &c., in streams. 
 
-"lkmaneaob^. 295 
 
 " From a oartilaginons disc, strongly applied to foreign bodies, proceed 
 a great number of close filaments, elastic, of a brownish -green colour, 
 and a little curved at the base, but they become more pale and straight 
 in the remainder of their length. These filaments are ordinarily from 4 
 to 7 inches in length. Some are entirely simple, the others throw out 
 here and there branches, or divide towards the middle of their length. 
 The internodes are oblong, from a line to a line and a half, cylindrical, 
 and inflated at their points of contact. Their divisions are often but little 
 apparent, and disappear towards the base of the filaments, which appear 
 continuous, cylindrical, and equal in diameter to a strong horse-hair. 
 The surface of the filaments in old age is encrusted in such a manner as 
 not to become recognizable either by its colour, which changes, or by the 
 destruction of the internodes, which become confused and disappear." — 
 Bory. 
 
 Plate CXXVIII. fig. 1. Filaments natural size ; a, portion of fila- 
 ment magnified j b. section of same ; c, chains of spores X 200. 
 
 Iiemanea tozulosa. (^Roth.) Ag. Spec. ii. 4. 
 
 Nearly simple, for the most part bent like a bow, 1-2 inches 
 long, nodules approximate, papilla flattened, sometimes con- 
 fluent or almost obsolete. 
 
 Size. Spores -04- x •022--03 mm. 
 
 Eabh. Alg. Eur. iii., 411. Kirch. Alg. ScHes. 43. Eng. 
 Fl. v., 322. Gray Arr. i., 288. Hass. Alg. 71, t. 7. 
 
 Conferva torulosa, Dillw. Conf. p. 77, t. f. 
 
 Conferva fluviatilis nodosa fucum emulans, Dill. Muse. t. 7, 
 f.48. 
 
 Lemanea jluviatilis, var. Q. torulosa, Eng. Bot. ii., t. 2423. 
 Harv. Mon. 119. 
 
 Conferva fluviatilis, var. 2. With. Arr. iv., 134. 
 
 In streams. 
 
 " From a little horny disc, fixed to the hard bodies which support it, 
 arise from six to thirty filaments, from one inch to 2J inches in length, 
 curved in one direction. Their colour is of a brownish or reddish-green, 
 obscure or livid. They acquire in diameter the greatest dimensions of 
 all the ConfervEB." — Bory. 
 
 Bory states that " M. Thore, of Dax, first remarked, in the Conferva 
 ftuviatilis of Linnaeus, a fact which is verified in the other species of our 
 genus. The recent filaments of this Lemanea, presented towards the 
 flame of a candle, explode and extinguish the candle. This phenomenon 
 does noc take place in dried specimens. It is owing to some gas shut 
 up in the connections of the joints, and which, put in expansion by the 
 heat, presses against the walls and breaks them with an explosion. A 
 remarkable movement of retraction is experienced in the fingei-s which 
 hold by the two extremities the filament experimented upon. As to the 
 smell of the burnt plant, although very peculiar, it cannot be compared 
 toHhat of animal substances submitted to the fire. I have not met with 
 any Lemania in stagnant waters ; they grow in quick waters. It is in 
 the pure fountains, large rivers, in very rapid rivulets, that they appear 
 to delight. Many, moreover, flourish especially in those places where 
 the current has the greatest %rce, such as in mill sluices, and the most 
 impetuous falls of cascades." — HassaU's Alga, p. 70. 
 
 plate CXXVIII, fiy. 2. Filaments natural size. 
 
SUPPLEMENT. 
 
 To follow at page 4 — 
 
 Fleuzococcus bituminosus. (JBory. Diet, iii., 15.) 
 
 Thallus mucous, brown-black, or pitch-colour, cells small, 
 rounded angular, greenish brown, 4-8 associated in families, 
 tegument scarcely broad, colourless, hyaline, indistinctly lamel- 
 lose. 
 
 Size. Cells -002 mm. ; families 0-1--02 mm. 
 
 Rabh. Alg. Eur. i., 28. 
 
 Chaos bituminosus, Bory. Diet, iii., 15. 
 
 Palmella hituminosa, Meneg. Nost. p. 56. 
 
 Protococcus hituminosus, Kutz. Tab. Phyc. i., t. 5. 
 
 Gleocapsa hituminosa, Kutz. Spec. 224. 
 
 On walls of damp cellars, &c. 
 Plate CXXIX. fig. 1. Cells and families x 400 diam. 
 
 Pleuzococcus vestitus. ^^nscK. Algen. Fl. p. 56. 
 
 Cells solitary, rarely united in small families, orange ; cell- 
 membrane thick, densely invested with small hairs. 
 
 Size. Cells •012--022 mm. diam. 
 
 Rabh. Alg. Eur. i., 29. 
 
 Acanthococcus vestitus, Lagerh. Srenska Vet. Akad. Forh., 
 1883, p. 37. 
 
 Plate CXXIX. fig. 2. CeUs X 400 diam. 
 
 Genus 14 Us. D&CTTLOCOCCUS. Nag. (1849). 
 
 Cells oblong or fusiform (at first ovate-cuspidate, then ellip- 
 soid), free swimming, 2-8 associated in families, at length 
 dividing and becoming single. 
 
 Propagation by division in one direction. 
 
 Sactylococcns De Bazyanus. Beinsch.. Gontril. t. x.,/. 1. 
 
 Cells broadly elliptical-oval, apex broadly rounded, base 
 attenuated into a hyaline pedicel, half as long as the cell, and 
 expanded at its extremity, single or twin, cell-contents intense 
 green, granulose, at length divided in 3 or 4. Cell membrane 
 thick. 
 
 Size. Cells -033 x -016 mm. 
 
 Parasitic on small aquatic crustaceans, Entomostraca, &c. 
 
 Plate CXXIX. fig. 3. a, indiTidnals x 400 diam. j h, two individuals 
 X 720 diam. 
 
SUPPLEMENT. 297 
 
 To be inserted at page, 91 — 
 Spizogyza velata. Nordst. Lund. Univ. Arsskrift, 1872, Vol. ix. 
 
 Sterile cells with the ends truncate, 3-4 times as long as 
 broad, chlorophyll band single, making 1^ to 2^ turns in the 
 spiral. 
 
 Spores elongated-oval, polymorphous, 1 ^ to 3 times as long 
 as broad ; epispore thick, composed of four membranes ; the 
 second is hyaline and scrobiculate ; the third is coloured 
 (Nordstedt). 
 
 Sporiferous cells a little swollen or not at all, sometimes 
 shorter, sometimes a little longer than the spores. 
 
 Size. Cells ■035--04mm. ; zygospore -06 X -035— -085 X 
 •045 mm. 
 
 Petit Spirogyra, p. 25, t. 7, fig. 1-5. 
 
 In ditches. 
 
 England (Leicester. P. Bates). 
 
 The zygospore has a broad hyaline border finely dentinnlate with the 
 scrobiculatlous of the second membrane. 
 
 Plate CXXX. fig. 1. a, sterile cells X 200 ; 6, sterile cell x 400 ; 
 e, fertile cells with zygospores X 200 diam. ; A, e, /, zygospores with the 
 investing cells X 400 diam. 
 
 At page 165, after 03. capillare, add — 
 
 CEdogonium capilliforme. Kutz. Spec. 367 (P). 
 
 Oogonia single, a little swollen, obversely egg-shaped, open- 
 ing with a superior pore ; oospores ellipsoid-globose or oylin- 
 drically globose (almost four-angled in optical section), not 
 filling the oogonia ; male plants a little more slender than the 
 females ; spermogonia 2-10 celled, alternating with the vegeta- 
 tive cells ; terminal cell obtuse. 
 
 Size. Cells of female ■03--034 mm., 1|- to 3 times as long ; 
 of male •024-'028 mm., 1^ times as long ; oogonium •042--048 
 X •051-"062 mm ; oospore •037-'045 x •04--05 mm., usually 
 •039--04; sperm, cell •02--025 x ■008--01 mm. 
 
 Wittr. Mon. (Edog. p. 31. Kutz. Tab. Phyc. iii., t. 37, f. 
 3 (?). 
 
 In pool and ditches. 
 
 Britain (Leicester. F. Bates). 
 
 J'late CXXIX, Jig. 4. o, female filament with oogonia X 400 diam. ) 
 6, male cells with alternating spermogonia X 400 diam. 
 
 2 T 
 
298 SUPPLEMKKT. 
 
 Insert at page 187 — 
 
 Chzoolepus nmbrinam. Kuiz. 
 
 Stratum thin, crnstaceous, rather pulverulent, reddish brown 
 growing pale when dead, threads and branches abbreviated, 
 tornlose, joints nearly as long as broad, broadly elliptic or sub- 
 globose. 
 
 Size. Cels -02 mm. diam. 
 
 Eabh. Alg. Eur. i., 372. 
 
 Protococcus crustaceus, Kutz. Spec. 203. 
 
 Protocorxus umhrinus, Kutz. Phyc. Gen., t. 7, f. 2. Cohn in 
 Hedwigia i.,p. 1. 
 
 On the bark of beech and oak. (Kelvedon. E. G. V.) 
 
 Plate CXXX. fig. 2. Chroolepas umbriniim X 400 diam. 
 
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 Grev. 8c. Crypt. Fl. Scottish Cryptogamic Flora, by E. K. 
 
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 London, 1833. 
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 Manchester, 1799. 
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 Acta Leop. Acad. 4o. 1857. 
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 Berlin, 1873. 
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AUTHOKTTIES QUOTED. 303 
 
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 Lager. Svbk. Algflora. Dr. G. Lagerheim, Sveriges 
 
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 MouG. & Nest. Exs. Stirpes Cryptogam* Vogeso-Rhenanee, 
 
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304 ACTHOEITIES QUOTED. 
 
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 1861. 
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AUTHORITIES QUOTED. 305 
 
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 1875. 
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 1856. 
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 "Walz in Prings. Jake.") Beitrag zur Morphologie und 
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 2 w 
 
306 AUTHORITIES QUOTED. 
 
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 WiTTH. Disp. CEdog. Dispositione CEdogoniacearnm Siieci- 
 
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 WiTTR. MoN. CEdog. Prodiomus Monographia (Edogoniea- 
 
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 WiTTR. MoN. PiTHOPH. On the development and systematic 
 
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 Fresh Water Algae of North America, by H. C. Wood 
 
 (Smithsonian Institution). Eoy. 4o., 21 pi. Wash- 
 ington, 1872. 
 WoRON. BoT. Zeit. Neuer Beitrage z Kenntniss der Chytri- 
 
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 Berlin, 1867. 
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 Green Alga, by Dr. E. P. Wright, in Transactions 
 
 Eoyal L-ish Academy. 4o. Dublin, 1877. 
 Wyatt, Alg. Exs. Algee Danmoniensis. 236 Spec. Exsic. 
 
 4o. Torquay. 
 
307 
 
 GLOSSAEY. 
 
 Achromatic (a, Gr. without, + chromos, colour). 
 
 Colourless. 
 AcictTLAR (acus, L. a needle). 
 
 Needle -shaped. 
 Acuminate (acumen, L. a point). 
 
 Tapering to a point. 
 j3Eeuginous {aerugo, L. rust of copper). 
 
 Of the colour of verdigris — blue green. 
 Agamo-hypnospores {agamos, Gr. unmarried, -f liypnospores). 
 
 Neutrally formed resting spores. 
 Agamospore (agamos, Gr. unmarried, + spore). 
 
 Spore formed neutrally without fecundation. 
 Agamospoeotjs (agamos, Gr. unmarried, + spore). 
 
 Bearing spores without fecundation. 
 Alternate (altemus, L. one after another). 
 
 Two organs so placed as not to be opposite to each other. 
 Amceboid (amoeba, + eidos, resemblance). 
 
 Eesembling an Amoeba. 
 Amorphous (a, Gr. without, + morphos, form). 
 
 Without definite form. 
 Amylaceous (amylon, Gr. flour). 
 
 Eesembling starch. 
 Anastomose (anastomo, Gr. to furnish with a mouth, to bring 
 
 to a mouth). 
 
 The opening of one vessel into another, applied to 
 
 threads or tubes which become confluent, and form an 
 
 irregular network. 
 Androgonidia (aner, Gr. a man, + gonidia). 
 
 Peculiar zoogonidia produced by female plants from 
 
 which male plants are developed. 
 Androspohangium (aner, Gr. a man, + sporangium). 
 
 Sporangium enclosing spores of male plants, or andro- 
 
 spores. 
 
308 GLOSSARY. 
 
 Androspore (aner, Gr. a man, + spora, a seed). 
 
 A special kind of zoospores produced in cells, whicli 
 originate the dwarf males in (Edogonium. 
 Anthbkidia (anther, -\. eidos, resemblance). 
 
 Certain reproductive organs supposed to be analogous to 
 anthers, or fecundative. 
 Apictjlus (diminutive of apex, L. a short point). 
 
 Ending with a short point. 
 Arcuate (arcuo, L. I bend like a bow). 
 
 Bent like a bow. 
 Areola (areola, L. a little space). 
 
 An angular space with an elevated margin. 
 Articulate {articulus, L. ajoint). 
 
 Composed of joints. 
 BiLOBATE (his, L. twice, + lobus, a lobe). 
 
 Having two lobes. 
 BiNATE [binus, from bis, L. by couples). 
 
 In pairs. 
 BoTRYoiD (botrys, Gr. a bunch of grapes). 
 
 Collected in clusters like a bunch of grapes. 
 Bdllate (bulla, L. a bubble). 
 
 Blistered or puckered. 
 C^spiTosE (ccespes, L. a turf or sod). 
 
 Growing in tufts, after the manner of a turf strictly, with 
 
 many stems from one root. 
 Capillary (capillus, L. a hair). 
 
 Thread-like, resembling a hair. 
 Carpobpore (carpos, a fruit, -|- spora, a seed). 
 
 Spores produced (by conjugation) in a sporo-carpium. 
 Cartilaginous (cartilago, L. a tendon). 
 
 Hard and tough like cartilage. 
 Cauloid (caulus L. a stalk or stem). 
 
 Resembling, or analogous to, a stem. 
 Chlorophyll (cMoros, Gr. green, -\- phyllon, a leaf). 
 
 The green colouring matter of leaves, and other green 
 
 parts of plants. 
 Chlorophyllose (ehloros, Gr. green, + phyllon, a leaf). 
 
 Resembling chlorophyll green. 
 CiLiATE (cilium, L. an eyelash). 
 
 Furnished, or fringed, with hairs. 
 CiLiUM, Cilia (cilium, L. an eyelash). 
 
 Hair or bristle placed marginally. 
 Circinatb (circino, L. I turn round). 
 
 Curled round, like the young frond of ferns. 
 CiRCUMScissiLB (cii'cum, L. around, + scindu, I cnt). 
 
 Cut round transversely. 
 Clathrate (elathms, L. a lattice) . 
 
 Latticed, or perforated Uke a window. 
 
GLOSSARY. 309 
 
 CcENOBiuM (coenobios, Gr. a community of living). 
 
 A community of a definite number of individuals united 
 
 in one body. 
 Concentrically {concentricus, L. with a common centre). 
 
 In rings, with a common centre. 
 Cordate (cor, L. the heart). 
 
 Heart-shaped. 
 Coriaceous (coriwn, L. leather). 
 
 Of a leathery consistence. 
 Corymbose (corymbos, Gr. the top, a cluster of fruit or 
 
 flowers). 
 
 Resembling the inflorescence called a corymb. 
 Crenatb (crena, L. a notch or cleft). 
 
 Notched or scalloped. 
 Crustaoeous {crusta, L. the hard surface of a body, the rind). 
 
 Hard and brittle, or forming a crust. 
 Cuneate (cuneus, L. a wedge). 
 
 Shaped like a wedge. 
 Cuspidate (cuspidatus, L. pointed). 
 
 Tapering gradually to a sharp, stiff point. 
 Cytoblast (cytos, Gr. a cell, + blastoa, a germ). 
 
 A cell germ. 
 Cytodbrm, Cytioderm {cytos, Gr. a cell, + rfenno*, a membrane). 
 
 Cell membrane. 
 Cytoplasma, Cytioplasm {cytos, Gr. a cell, -{-plasma, formation). 
 
 Cell contents. 
 Decussate {deoussatus, L. cut crossways like the number X, 
 
 decern) . 
 
 In pairs, alternately crossing. 
 Dehiscence (dehisco, L. 1 gape). 
 
 Splitting into regular parts. 
 Diaphanous {dia, Gr. through, + phaino, I show). 
 
 Nearly transparent. 
 DiCHOTOMOus {dichotomos, Gr. divided in two) . 
 
 Forked equally. 
 Diffluent {diffluo, L. I flow). 
 
 Readily dissolving. 
 Difficious, Dioicous {dis, Gr. twice, + oikos, a house). 
 
 When the male organs are borne on one plant and the 
 
 female on another. 
 Dissepiment {dissepio, L. I separate). 
 
 A partition or division. 
 Encysted {en, Gr. within, + cystis, a bladder). 
 
 Enclosed in a cyst or bladder. 
 Endochrome {endon, Gr. within, -|- chromos, colour). 
 
 Cell contents. Colouring matter of cells. 
 Endophytal {endon, Gr. within, + phyton, a plant). 
 
 Growing within plants. 
 
310 
 
 6L08SART. 
 
 Endosmose (endon, Gr. within, -|- osmos, impulsion). 
 
 The inward current established between fluids of different 
 
 densities when separated by a membrane. 
 Endosporhjm, Endospore (endon, Gr. within, + spora, a spore). 
 
 The inner coating of a spore. 
 EpiGYNons (epi, Gr. upon, + gyne, a female). 
 
 Seated upon the female organ. 
 Epiphytal (epi, Gr. upon, + phyton, a plant). 
 
 Growing upon plants. 
 Epispore {epi, Gr. upon, + spora, a seed). 
 
 The outer integument of a spore. 
 Epizoic (epi, Gr. upon, + zoon, an animal). 
 
 Growing upon animals. 
 ExospoRiirai, ExosPORE (exo, Gr. outwards, + «pora, a spore). 
 
 The outer membrane of the coat of a spore. 
 Fascicle (Jascicula, L. a little bundle). 
 
 A bundle. 
 Fasciculate {fascicula, L. a little bundle). 
 
 In bundles from a common point. 
 FiLAMBNTOSE {filum, L. a thread). 
 
 Composed of threads. Thread-like. 
 FoLiACEOus (Jblium, L. a leaf). 
 
 Resembling a leaf. 
 FuRFURACEODS (fuvfur, L. brau). 
 
 Mealy, or resembling meal. 
 Geminate (gemini, L. twins). 
 
 Produced in pairs. 
 Genuflexuous (genu, L. a knee, +flecto, I bend). 
 
 Bent angularly like a knee joint. 
 Gonidia (gone, Gr. offspring, seed, + eidos, resemblance). 
 
 Propagatire bodies of small size not produced directly or 
 
 indirectly by any act of fertilization. 
 Gonosphere (gonos, Gr. seed, + sphcera, a ball). 
 
 A ball-like agglomeration of spores. 
 Gynandeosporods (gyne, Gr a woman, + aner, a man). 
 
 Bearing male and female spores. 
 Hamate (hamug, L. a hook) . 
 
 Hook-shaped, resembling a hook. 
 Heterocyst (heteros, Gr. diverse, -t- cystos, a bladder). 
 
 Intercalated cells of a special character differing from 
 
 their neighbours. 
 Heterogenods (heteros, Gr. another, -I- genos, race, family). 
 
 Unhke, or dissimilar in kind. 
 Hexahedrical (hex, Gr. six, -I- hedron, a side). 
 
 Having six sides. 
 Homogenous (homos, Gr. alike, + genos, race, family). 
 
 Of the same kind. Consisting of elements of a like nature. 
 HoRHOGONE (hormos, Gr. a necklace,-!- gone, offspring). 
 
 Special reproductive bodies, composed of a chain of cells. 
 
GLOSSARY. 311 
 
 Hyaline Qiyalos, Gr. glass). 
 
 Transparent, resembling glass. 
 Hypnosporangium, Hypnosporangb (hypnos, Gr. sleep). 
 
 Sporangium enclosing hypnospures. 
 Hypnospoeb (Jiypnos, Gr. sleep + spore). 
 
 Spores which repose some time before germinating = 
 
 " resting spores." 
 HypoGYNOus {hypo, Gr. under, + gyne, a woman). 
 
 Seated beneath the female organ. 
 Idio-androsporous {idios, Gr. proper, + androspores). 
 
 Neuterindividuals, producingandrospores(in (Edogoniuvi). 
 Intbroalatbd {inter-calare, L. to insert in the calendar). 
 
 Interspersed, placed between others. 
 Intercbllular {inter, L. between, + cellular). 
 
 Between the cells. 
 Intbrstitial {interstitiuin, L. a space between). 
 
 Placed between. 
 Isolated {insula, L. an island, through the Italian isola). 
 
 Detached, placed by itself. 
 IsospoRE {isos, Gr. equal, + spora, a seed). 
 
 Applied to spores which are all of one size, or kind, in 
 
 the same plant. 
 Lacuna {lacuna, L. a little hole). 
 
 A depression, cavity, or intercellular space. 
 Lamella {lamellw, L. thin plates of metal). 
 
 Thin plates or membranes parallel to each other. 
 Lambllose {lamellce, L. thin plates of metal). 
 
 Formed of layers or plates superimposed. 
 Lubricous {lubricus, L. slippery). 
 
 Slippery. 
 Lunate {lima, L. the moon). 
 
 Crescent-shaped. 
 Macrandkous {macros, Gr. large, long, -f aner, a man). 
 
 Having elongated male plants. 
 Maceogonidia {macros, Gr. large, long, + gouidia). 
 
 Large gonidia. 
 Matrical {matrix, L. the womb). 
 
 Belonging to the matrix. 
 Mesophyllic (mesas, Gr. middle, + phyllos, a leaf). 
 
 In the middle of a leaf or frond. 
 Mbsospoeium, Mbsosporb {mesas, Gr. middle, + spora, a spore). 
 
 The middle membrane of the coat of a spore. 
 Metagenesis {meta, Gr. after, + genesis, origin). 
 
 A kind of alternation of generations. 
 MicROGONiDiA {micros, Gr. small, + gonidia). 
 
 Small gonidia. 
 Micropylb {micros, Gr. small, + pyle, gate). 
 
 The aperture in the skin of a seed which was the 
 
 foramen in the ovule. A little scar. 
 
312 GLOSSARY. 
 
 Mobile (mohilis, L. movable). 
 
 Movable. 
 MoNiLiFOKM, {monile, L. necklace, + forma, shape). 
 
 Necklace-shaped, contracted at regular intervals. 
 MoNoicons, MoNCBCious, {monos, Gr. one, + oikos, a house). 
 
 With male and female organs on the same plant. 
 Multicellular (multus, L. many, + cellula, a little cell). 
 
 Composed of many cells. 
 MuLTiLocuLAR (multus, L. many, + loculus, a little place). 
 
 Containing many cells or cavities. 
 Multi-partite (multus, L. many, + partite). 
 
 Divided into many parts. 
 Nanandrous (nanos, Gr. a dwarf, + aner, a manj. 
 
 Having short or dwarf male plants. 
 Nodulose (iwdulus, L. a little knot). 
 
 Knotted, or with swollen joints. 
 Nucleus (nucleus, L. a kernel). 
 
 The central germ around which a cell is formed. Small 
 
 spherical bodies contained within spores or other cells. 
 Obcordatb (ob, L. inversely + cor, the heart). 
 
 Inversely heart-shaped. 
 Octonate [octo, Gr. eight). 
 
 Eight together. 
 Oleaginous (oleaginus, L. of an olive tree). 
 
 Oily, or resembling oil. 
 Oogonium (om, Gr. egg, + gonos, seed). 
 
 A kind of ovarian sac containing spores which, when 
 
 liberated, are called oospores. 
 Oospore (con, Gr. an egg, + spora, a, seed). 
 
 Spores produced in an ovarian sac. 
 Operculum (operculum, L. a cover or lid). 
 
 The lid or cover of a capsule. 
 Parenchyma (parenchyma, Gr. anything poured in beside). 
 
 Compressed or hexagonal celhilar tissue. 
 Parenchymatous (parenchyma, Gr.). 
 
 Resembling the cellular tissue termed " parenchyma." 
 Parietal (paries, L. a wall). 
 
 Growing by, or to, the wall. 
 Parthenogenesis (parthenos, Gr. virgin, + genesis, origin). 
 
 Production of fertile seeds without sexual impregnation . 
 Parthenogonidia (parthenos, Gr, a virgin, -|- gonidia). 
 
 Gonidia produced without fecundation. 
 Patent (pateo, L. I am open). 
 
 Spreading. 
 Pectinate (pecten, L. a comb) . 
 
 Pinnatifid, with narrow close segments, like the tooth of 
 
 a comb. 
 Pedicellate (pediculus, L. a little foot). 
 
 Having a foot, or stem. 
 
GLOSSARY. 313 
 
 Pentahedrioal {pente, Gr. five, + hedron, a side). 
 
 Having five sides. 
 Pericakpidm (peri, Gr. around, + carpos, a fruit). 
 
 Covering or tegument of fruit. 
 Periderm, Peri dermic {peri, Gr. around, + derma, skin). 
 
 The enclosing membrane. 
 Peripheral [peri, Gr. around, + phero, to carry). 
 
 The outer portion of a circle. 
 PiLiFBRons (pilus, L. a hair, + fero, I bear). 
 
 Bearing hairs, hairy. 
 Plicate (plica, L. a plait). 
 
 Folded, or plaited. 
 Plumose (phtma, L. a feather). 
 
 Feathery, or like a feather. 
 Polymorphism, Polymorphic, (polus, Gr. many, + morphos, 
 
 form). 
 
 Having many forms. 
 Primordial ('primordium, L. beginning). 
 
 Original, existing from the beginning. 
 Prothallus (pro, Gr. before, -|- thallus, a frond). 
 
 The false thallus first formed on germination of a 
 
 spore. 
 Pseudo-branches (pseudos, Gr. false, + branches) . 
 
 False branches, or resembling branches. 
 Pseudo-ramose (pseudos, Gr. false, -|- ramus, a branch). 
 
 Having false branches. 
 Pyriporm (pyrns, L. a pear, + forma, form). 
 
 Pear-shaped. 
 Qdadri-radiate (quadrum, L. four-square, -|- radiate). 
 
 With four radii, or rays. 
 QuATBRNATE (quater, L. four times). 
 
 Arranged in fours. 
 Eamulus (diminutive of ramus, L. a branch). 
 
 A small, or secondary branch. 
 Reniporm (renes, L. the kidneys, -|- forma, shape). 
 
 Kidney-shaped. 
 Replicate (re, L. back, -)- -pl^co, I fold). 
 
 Folded back. 
 Resting-sporb. a spore which becomes quiescent, or rests for 
 
 a period, more or less long, before germination. 
 Ehizoid (rhiia, Gr. a root, -I- eidos, resemblance.) 
 
 Resembling, or analogous to, a root. 
 Rostrate [rostrum, L. a beak). 
 
 Terminating with a beak. 
 Saccate (saccus, L. a sac). 
 
 In the form of a bag. 
 Scalariform (scula, L. a ladder, + forma, shape). 
 
 Barred or crossed like the steps of a ladder. 
 
 2 X 
 
314 GLOSSABY. 
 
 ScROBicuLATE (scroMculus , L. a little ditch). 
 
 Marked with little pits or depressions. 
 Scutate (scutum, L. a shield). 
 
 Buckler-shaped. 
 Segmentation (segmentum, L. a segment). 
 
 Dividing into segments. 
 Segregate (segrego, L. I separate). 
 
 To separate from others, or set apart. 
 Semi- (L. half). 
 
 Prefix signifying " half." 
 Septum {septum, L. a hedge). 
 
 A partition or division. 
 Sigmoid (sigma, Gr. the letter S). 
 
 Shaped like the letter S. 
 Sinus {sinus, L. a hollow). 
 
 A depression or notch. 
 Spermatozoa, Spermatozoids {spei-ma, Gr. a seed, -f zoon, an 
 
 animal). 
 
 Thread-like bodies possessed of motion, supposed to 
 
 have fecundative power. 
 Sporangium, Sporangia {spora, Gr. a seed, + angos, a vessel). 
 
 A spore-case, having spores produced within it. 
 Sporiferous {spora, Gr. a seed, -|- fero, I bearj. 
 
 Bearing spores. 
 Sporocarpium {spora, Gr. a seed, -|- carpos, a fruit). 
 
 Covering or capsule enclosing spores, or carpospores. 
 Spobodekm {spora, Gr. a seed, -|- derma, a membrane. 
 
 The coating or covering of a spore. 
 Sporules (diminutive of spore). 
 
 Minute spore-like bodies. 
 Stratose (stratum, L. a couch or bed). 
 
 Arranged in layers or strata. 
 Stratum (L. a couch or bed). 
 
 A layer, or extended bed. 
 Stri^ (stria, L. a groove or furrow). 
 
 Parallel lines or shallow grooves. 
 Sub- (L. under) . 
 
 A common prefix indicating " almost " or '■ nearly." 
 Subulate (subula, L. an awl). 
 
 Shaped Hke an awl. 
 Tangentiai, (tangens, L. touching). 
 
 In the direction of a tangent. Touching a straight line 
 
 on the arc of a circle. 
 Tegument (tego, L. I cover). 
 
 A covering or membrane. 
 Terete (teres, L. long, round, and tapering). 
 
 Cylindrical, tapering like the trunk of a tree. 
 Tetrahedrical (tetra, Gr. four, -|- hedron, a side). 
 
 Having four sides. 
 
GLOSSARY. 
 
 315 
 
 Tbteaspoebs (tetra, Gr. four, + spores). 
 Certain spores produced in fours. 
 Thalltjs (thallos, Gr. a frond). 
 
 An expansion somewhat resembling a leaf. 
 ToEULOSE (torulus, L. a little cord). 
 
 Almost synonymous with moniliform. 
 Trichogonia (thrix, Gr. the hair, + gonos, generation). 
 
 The female reproductive organs in Batrachosperms. 
 Teichomb (thrix, Gr. the hair). 
 
 The thread or filament of filamentous algse. 
 Teichotomous (tricha, Gr. threefold, + temno, I cut). 
 
 Dividing in threes. 
 Tedncatb {truncus, L. a stump). 
 
 Terminating very abruptly. 
 TuBKECULATB (tuberculum, L. a pimple). 
 
 Covered with warts or tubercles. 
 Unicblltjlae (unus, L. one, + cella, a cellar). 
 
 Literally, composed of one cell. 
 Vacuole (vacuus, L. empty). 
 
 Drops which are seen in the interior of the protoplasm 
 
 of cells. 
 Vagina, Vaginatb (vagina, L. a sheath). 
 
 A sheath, sheathing. 
 Veeeucosb (verruca, L. a wart). 
 
 Covered with warts. 
 Vbeticillate (verticillus, L. a whorl). 
 
 Arranged in whorls. 
 Vesicle [vesicula, L. a little bladder). 
 
 A bladder-like cavity. 
 ViBRATiLB (vibro, L. to quiver or shake). 
 
 That moves to and fro, or vibrates. 
 ZooGONiDiA (zoon, Gr. animal, + gonidia, which see). 
 
 Gonidia endowed with, active motion. 
 ZoospoEANGiuM, ZoospORANGE (^0071, Gr., an animal, + sporan- 
 gium). 
 
 Sporangium enclosing zoospores. 
 Zoospores (zoon, Gr, an animal, -|- spora, a spore). 
 
 Locomotive spores. 
 Zygospore (zygos, Gr. a yoke, marriage, + spora). 
 
 A spore resulting from conjugation- 
 
316 
 
 INDEX. 
 
 AOARDHIA. 
 
 carrulescens. Gray 
 
 A I If ACT [S. 
 
 calcarea. Kutz. 
 Amphicomum. 
 
 awreum. Johnst . 
 Anabaena. Bory. . 
 
 circinalis. Phil. . 
 
 circinalis. Habh. 
 
 fioS'aqucB. Hass. 
 
 flos-aqucB, Eabh. 
 
 flos-aqaae. Kutz. 
 
 grdrmlaris. Kutz. 
 
 Hassallii. ^V. <fc Witt. 
 
 iynpalpehralis. Hass. 
 
 inaeqaalis. Br. 
 
 intricata. Kntz. 
 
 lichenifoi'niis. Hass. 
 
 oscillarioides. Bory. 
 
 Balfsii. {Kutz.) . . 
 
 Smithii. N. ^ Witt. 
 
 spiralis. Thoinp. 
 
 Thwaitesii. (Ralfs.). 
 
 variabilis. Kut-. 
 Ajtacystis. 
 
 marginata. Men. 
 Ankisteodesmtjs. 
 
 acutissimus. Ar. 
 
 falcatns. Ralfs. 
 
 gregarius. Breb. 
 Aphanizomenon. Mor. 
 
 flos-aquEB. Balfs. . 
 
 incurvum. Mor. 
 Aphanocapsa. A'ag. . 
 
 depresaa. Rabh. 
 
 Grevillei. Raih. . 
 
 parietina. Nag. 
 
 rivularis. Rabh. 
 
 virescens. Rabh. 
 Aphanochaete. Br. . 
 
 hjstrix. Rabh. 
 
 repens. Jir. . . 
 AphiUiothece. Nag. . 
 
 Mooreana. Lager. . 
 
 prasina. Br. , . 
 
 stagnina. Rabh. 
 
 PAGE. 
 
 
 PAGE 
 
 
 Apiocystis. Xag. 
 
 . . 17 
 
 . . 107 
 
 Branniana. ^^ag. 
 Arthronema. 
 
 . . . 18 
 
 . . 279 
 
 cirr}u)sun\. Hass. 
 Artheosiphon. 
 
 . . 270 
 
 . . 185 
 
 alatii.t. Rabh. 
 
 . . 267 
 
 231 
 
 Grevillei. Kutz. 
 
 . . 267 
 
 . . 237 
 
 Aktheospira. 
 
 
 . . 235 
 
 Jenneri. Hedw. 
 
 . . 245 
 
 . . 236 
 
 Bangia. Lyngb. 
 
 . . 282 
 
 . . 227 
 
 atro-purpurea. Ag. 
 
 . . 282 
 
 . . 235 
 
 calophylla. Carm. 
 
 . . 130 
 
 . . 231 
 
 Batrachospezmam. 
 
 Bory. 286 
 
 . 236 
 
 alpestre. Hass. 
 
 . . 290 
 
 . 244 
 
 atrnm. Barv. . 
 
 . 292 
 
 . . 239 
 
 hambusimtm. Bory. 
 
 . 291 
 
 . . 227 
 
 Boltoni. Cke. 
 
 . . 290 
 
 . 236 
 
 confusum. Hass. 
 
 . . 289 
 
 . 238 
 
 conglomeratum. Vanch. 191 
 
 . . 237 
 
 detersum. E. Bot. 
 
 . . 292 
 
 . 237 
 
 JHllenii. Bory. 
 
 . . .293 
 
 . . 235 
 
 fasdculatnm. Vauc 
 
 h. . 195 
 
 . 238 
 
 giganteum. Kutz. 
 
 . . 289 
 
 . . 236 
 
 helmintosiim. Hasa 
 
 . . .293 
 
 
 hispidum. D.C. 
 
 . . 291 
 
 . . 212 
 
 ieratophyta. Bory. 
 
 . . 292 
 
 
 ludibunda. Bory. 
 
 . 288,290 
 
 . . 19 
 
 momliforme. Roth. 
 
 . . 288 
 
 . . 19 
 
 myosuriis. Duel. 
 
 . . 25 
 
 . . 19 
 
 proliferum. Hass. 
 
 . . 289 
 
 . 239 
 
 ptilcherrirmim. Has 
 
 a. . 288 
 
 . . 240 
 
 ruhrum. Hass. 
 
 . . .285 
 
 . . 240 
 
 setigerum. Rabh. 
 
 . . 288 
 
 . . 210 
 
 stagnate. Hass. 
 
 . . .290 
 
 . . 211 
 
 suevoriim. Kntz. 
 
 . . .292 
 
 . . 210 
 
 turfosa. Bory. 
 
 . . .291 
 
 . . 210 
 
 vagum. Ag. 
 
 . . .291 
 
 . . 210 
 
 Belonia. 
 
 
 . . 210 
 
 torulosa. Carm. 
 
 . . .240 
 
 . . 197 
 
 BOTRTDIACE.E. . . 
 
 . . Ill 
 
 . . 197 
 
 Botzydina . . . 
 
 . . 14 
 
 . . 197 
 
 Grevillei. Men. 
 
 . . ,211 
 
 218 
 
 Tulgaris. Breb. 
 
 . . . 14 
 
 . . 218 
 
 Botzydinm. Wallr. 
 
 . . . Ill 
 
 . . 218 
 
 argillacetim. Grev. 
 
 114 
 
 . . 219 
 
 granulatam. Linn. 
 
 . . 114 
 
INDEX., 
 
 317 
 
 Botxyococcus. K. 
 
 Braunii. Kittz. 
 Bulbochaete. Ag. 
 
 Brebissonii. Kutz. 
 
 gigantea. Pr. 
 
 giraoilia. Prings. 
 
 inBignis. Frings. 
 
 intermedia. S.By. 
 
 mirabilis. Wittr, 
 
 polyandra. Oleve. 
 
 Pringsfieimiana. Ar. 
 
 pygmsea. Wittr. 
 
 rectangularis. Wittr 
 
 Hothii. Gray. 
 
 setigera. Ag. 
 Byssus. 
 
 aurea. E. Bot. 
 
 hotryoides. Hads. 
 
 botryoides virens. Ray 
 
 jios-aquce. Linn. 
 
 iolithus. Linn. 
 
 nigra. E. Bot. 
 
 pulverulenta . Dillen. 
 Calothxix. Ag. . . 
 
 atrovirens. Harv, 
 
 Brebissonii. Kutz. 
 
 Dillwyni. Mass. . 
 
 distorta, Harv. . 
 
 interrupta. Carm. 
 
 lucifuga. Carm. , 
 
 mirabiUs. Ag. 
 
 Orsiniana. Thtir. 
 
 Smithii. Berh. . 
 Calotkiohejs. . . 
 Cekakium. 
 
 aureum. Hook. . 
 Chaetomorpha. Kutz. 
 
 implexa. Katz. . 
 
 linam. Kutz. 
 
 litorea. Harv, 
 
 satoria. Berk. 
 
 CHa;TOPHOEACEiE. 
 
 Chsetophora. Schr. 
 elegans. Aff. . . 
 elega/ns. Lyngb. 
 endivEefolia. Ag, 
 fastigiata. Balfs. 
 pisiformis. Ag. . 
 punctiformis. Kntz, 
 tuberonlosa. Ag. 
 
 CnANTKANSIAOE*. 
 
 Chantzamsia. Fr. , 
 
 chalybea. Kutz. 
 oompacta. Rolfs. 
 Hermann!. Kutz. 
 investiena. Kutz. 
 pygmaea. Kutz, . 
 Bcotica. Kutz. 
 violacea. Kutz. , 
 
 PAGE 
 
 . 17 
 
 . 17 
 
 . 173 
 
 . 175 
 
 . 175 
 
 . 177 
 
 . 176 
 
 . 174 
 
 . 176 
 
 . 174 
 
 . 177 
 
 . 176 
 
 . 177 
 
 . 175 
 
 . 175 
 
 . 185 
 . 211 
 . 211 
 . 240 
 . 116 
 . 187 
 . 211 
 . 275 
 . 263 
 . 263 
 . 276 
 . 270 
 . 266 
 . 262 
 . 263 
 . 276 
 . 277 
 . 275 
 
 , 185 
 
 138 
 
 , 140 
 
 . 139 
 
 , 138 
 
 , 139 
 
 188 
 
 . 193 
 
 194 
 
 194 
 
 194 
 
 191 
 
 193 
 
 195, 278 
 
 194 
 
 283 
 
 283 
 
 . 284 
 
 286 
 
 284 
 
 285 
 
 285 
 
 285 
 
 283 
 
 CHAKACIEjE 
 
 Chazacium. Br. . . 
 
 amiiguum. Eabh. . 
 
 ornithocephalnm. Br. 
 
 Sieboldi. Br. ... 
 
 tenne. Herm. . . 
 Chlamydococcus. Br, 
 
 nivalis. Br. . . . 
 
 plnvialis. Br. . . 
 Chlamydomonas. Mhr. 
 
 pulvisouluB. Bhr. , 
 Chlozochytzium, Cohn, 
 
 Lemnas. Colin. . , 
 Chlozococcum. Fr. . 
 
 friistnlosum. Babh. 
 
 gigas. Onm. 
 
 humioolam. Nag. 
 
 murorum. Rabh. 
 
 vulgare. Grev. . 
 
 ChLOKOPHTLLOPHYOE/E, 
 
 Cblorosph^ra. 
 
 OUvn'i. Henf. . 
 Choaspks. 
 
 serjtentina. Gray 
 Cheoococcace.*;. 
 Chzoococcus. Naff. 
 
 cohserens. Naff. 
 
 turgidas. JVag. , 
 CheoolepidjE. . . 
 Chzoolepus. Aff. . 
 
 ubietimim. Kabh. 
 
 Arnotti. Harv. . 
 
 aureus. Linn. 
 
 ebenea. Harv. 
 
 ilioioolna. M Bot. 
 , iolithus. lAnn. , 
 
 liohenioolus. Ag, 
 
 melaenus. Carm. 
 
 mesomelas. Carm. 
 
 odoratua. I/yngb. 
 
 umbrinus. Kutz. 
 Chthonoblastus. 
 
 anguiformis. Kutz. 
 
 Lyngiyei. Kutz. 
 
 repens. Kutz. 
 
 saUriMS, Kutz. 
 Chttkidie^, . . . 
 Chytzidium. Br. , 
 
 acuminatum, Br. 
 
 ampullacevm. Br. 
 
 anemones. D. By. 
 
 Barherianum. Ar. 
 Cladophoza. JSufe. . 
 
 canalicularis. Kutz. 
 
 crispatO: Hasa. . 
 
 crispata Kutz. , 
 
 flavesoens. Ag. 
 
 Jla/vida. Kutz. 
 
 fracta. Kutz, 
 
 page 
 . 47 
 . 47 
 . 48 
 . 48 
 . 48 
 . 48 
 . 50 
 . 54 
 . 51 
 . 55 
 . 56 
 . 202 
 . 202 
 . 30 
 . 30 
 . 31 
 . 30 
 . 30 
 4 
 . 1 
 
 97 
 
 203 
 203 
 204 
 204 
 184 
 184 
 187 
 187 
 185 
 187 
 186 
 186 
 187 
 187 
 187 
 186 
 297 
 
 255 
 255 
 256 
 255 
 193 
 198 
 199 
 200 
 201 
 199 
 141 
 144 
 142 
 143 
 144 
 144 
 142 
 
318 
 
 EJDBX. 
 
 Clasophoba — (cmiMniied^j 
 
 PAGE 
 
 CoNFEKVA — {continued) 
 
 PAGE 
 
 glomerata. Linn. . 
 
 . . 140 
 
 caerulescens. Eng. Bot. 
 
 . 107 
 
 SBgagropila. Eutz. . 
 
 . . 145 
 
 corymbosa. E. Bot. 
 
 . . 284 
 
 ClaXbxocystxs. Benf. . 
 
 . 212 
 
 crassa. Engl PI. 
 
 . . 139 
 
 aeruginosa. Henf. . 
 
 . . 212 
 
 crispata. Dillw. 
 
 . . 143 
 
 roseo-periicina. Cohn 
 
 6, 213 
 
 cyanea. Eng. Bot. . 
 
 . . 266 
 
 CLOSTERIlir. 
 
 
 LanuB-cornu. Kay . 
 
 . 195 
 
 falcatxim. Men. . . 
 
 . . 19 
 
 derorticans. Dillw. 
 
 . 260 
 
 Ch-iffithii. B. . . . 
 
 . . 19 
 
 decnisata. Dillw. 
 
 . . 77 
 
 Cluzella. 
 
 
 dichotonia. DiUen . 
 
 . . 120 
 
 myomrus. Bory. 
 
 . . 25 
 
 dUtorta. Dillw. . . 
 
 268, 270 
 
 COCCOCHLORIS 
 
 
 ebenea. Dillw. . . 
 
 . 187 
 
 cystifera. Hass. . . 
 
 218 
 
 ecUnata, E. Bot. . 195. 278 
 
 depressa. Men. . . 
 
 211 
 
 echinvlata. Gray . 
 
 . 278 
 
 Ch-evillei. Hass. . . 
 
 . . 211 
 
 ericetorvm. Harv. . 
 
 . 98 
 
 hyalina. Hass. . . 
 
 11, 219 
 
 exigva. Dillw. . . 
 
 . 189 
 
 hyalina. Men. 
 
 . . 11 
 
 ftavescens. Dillw. . 
 
 . 144 
 
 Mooreana. Hass. 
 
 12 
 
 fioccosa. Ag. . . . 
 
 . 136 
 
 qitatemaia. Breb. . 
 
 207 
 
 fiuriatilis. Dillw. . 
 
 . 291 
 
 radicata. Johnst. 
 
 . . 211 
 
 fontaTia nodosa. Dill. ' 
 
 390, 293 
 
 rivularis. Hass. 
 
 . . 210 
 
 fontana nodosa. Ray 
 
 . 288 
 
 stat/nina. Spr. . . 
 
 . . 219 
 
 fontinalis. Berls. 
 
 . 137 
 
 stag)! ii! a. West . . 
 
 . . 218 
 
 fontinalis. Dillw. . 
 
 . 252 
 
 CoccoPHYCE.E. ; ; . 
 
 2 
 
 fontinalis. Ray . . 
 
 . 143 
 
 Codiolum. Br. . . 
 
 . . 49 
 
 fracta. Eng. PI. . . 
 
 . 142 
 
 gregarinm. Br. . 
 
 . . 49 
 
 frigida. Dillw. . . 
 
 122 
 
 Coelastzum. Nag] . . 
 
 . . 45 
 
 fiigaeissima. Dill. . 
 
 . 136 
 
 cambrioum. Ar. 
 
 . 46 
 
 fugacissima. Grev. 
 
 . 135 
 
 microspormn. Sr. . 
 
 . . 46 
 
 gelatinosa. DiUw. . 
 
 . 288 
 
 jyaegelK. Kabh. 
 
 . . 45 
 
 gemiflexa. Dillw. . 
 
 . 105 
 
 sphsBricum. Nag. . 
 
 . . 45 
 
 globosa. Phil. Trans. 
 
 . 145 
 
 CcelOBphaexium. Nag. 
 
 . . 213 
 
 gh>merata. Linn. 
 
 . 143 
 
 Kntzingianum. Nag. 
 
 213 
 
 ilicicola. E. Bot. . 
 
 . 186 
 
 C<ENOCOLEUS. 
 
 
 implexa. Dillw. . . 
 
 . 1410 
 
 cirrhosus. Berk. 
 
 . . 276 
 
 inflata. Eng. Bot. . 
 
 . 90 
 
 Smithii. Berk. . . 
 
 . 277 
 
 jugalis. Dillw. 
 
 90,86 
 
 Coleochaete. Breb. 
 
 . . 195 
 
 Uchenicola. E. Bot . 
 
 . 187 
 
 orbicularis. Brings. 
 
 . . 197 
 
 limosa. Fl. Dan. 
 
 . 251 
 
 scutata. Breb. . . 
 
 196 
 
 linum. Ag. 
 
 . 139 
 
 Boluta. Brings. . . 
 
 . 196 
 
 Unum. Harv. . . 
 
 138 
 
 Confezva. X. ... 
 
 . . 136 
 
 litorea. Harv. . . 
 
 . 138 
 
 agagropila. Linn. . 
 
 . . 145 
 
 liibrica. Dillw. . . 
 
 180, 189 
 
 agagropilaris. Gray 
 
 . . 145 
 
 hibrica. Eng. Bot. . 
 
 . 193 
 
 alpina. Eng. PI. 
 
 . . 98 
 
 lubrica. Roth. . . . 
 
 . 16 
 
 amphibia. Dilliv. 
 
 . . 123 
 
 lucciis. E. Bot. . . 
 
 . 180 
 
 amphibia. Ray . . 
 
 . . 122 
 
 ■marina trichodes. Ray 
 
 . 142 
 
 annulina. Both. 
 
 . . 134 
 
 melaena. Lyngb. 
 
 . 187 
 
 arenicota. Berk. 
 
 141 
 
 mirabilis. Dillw. 
 
 . 263 
 
 atra. Dillw. . . . 
 
 . . 292 
 
 muralis. Dillw. . . 
 
 . 183 
 
 atrapurpurea. Dillw. 
 
 283 
 
 mvtabilis. Dillw. . 
 
 . 191 
 
 aurea. Dillw. . . 
 
 . 185 
 
 myochrous. Dillw. . 
 
 . 265 
 
 Hcolor. E. Bot. . 
 
 181 
 
 ■nana. Dillw. . . ,. 
 
 190,284 
 
 bipunctata. Dillw. . 
 
 . . 79 
 
 nilidum. Dillw. . *. 
 
 . 87 
 
 hipunctata. Eng. Bot. 
 
 . 77 
 
 ooellata. Dillw. . . 
 
 . 271 
 
 bombycina, Jg. 
 
 137 
 
 ochracea. Dillw. 
 
 • 258 
 
 bombycina. Kntz. . 
 
 . . 135 
 
 odoraia. Lyngb. 
 
 . 186 
 
 Brou-iiii. Dillw. 
 
 . 145 
 
 pinnatula. Dillw. . 
 
 . 144 
 
 canalicularis. Sibth. 
 
 . 144 
 
 PUnii. Ray . . . 
 
 . 120 
 
 capillaris. Hnds. . 
 
 . . 139 
 
 protensa. DUlw. 
 
 . 190 
 
 clutlybea. Dillw. 
 
 284 
 
 purpurascens. Caiin. 
 
 . . 99 
 
319 
 
 CoNFEavA — {continued) 
 reticulata. Dill. . 
 sordida,. Dillw. . 
 spiralis. Dillw. . 
 stictica. Eng. Bot. 
 sutoria. Berk. 
 sutoria. Croiian . 
 tenerrima. Eutz. 
 terrestris. Bay . 
 torulosa. Dillw. . 
 undulata. Breb. . 
 vagabunda. Huds. 
 vaginata. Dillw, 
 vaginata. B. Bot. 
 vesicata. Dillw. . 
 vesieata, Lyngb. 
 vivipara. Dillw. . 
 vulgaris. Kirsoh. 
 zonata. W. & M. 
 
 CONFEBVACE*. . . 
 
 CONJUOATA. 
 
 condensata. Tauoh. 
 cruciata. Vauch. 
 decimina. Gray. 
 gracilis. Tauch. 
 inflata. Gray. 
 infiafa. Yaucli. . 
 longata. Vanch, 
 pectinata. Vauch. 
 porticalis. Tanoh. 
 princeps. Taucli. 
 qvAnina. Gray. . 
 siellina. Tauoh. 
 
 COSMOCLADIUM. 
 
 saxonicu7n. D.By. 
 Cylindrocapsa. Bein, 
 
 involuta. Rein. 
 
 nuda. Rein. . 
 Cylindzospexmum, Balfi 
 
 catenatum. Balfs 
 
 elongatum, Kutz. . 
 
 leptospermum. Kutz, 
 
 licheniforme. Kutz, 
 
 maorospermum. Kutz, 
 
 Bal/sii. Kutz. . . 
 Cymatonema. 
 
 confervaceum. Kutz 
 Ctstiphoe^. . . . 
 Ctstococcus. 
 
 humicola. Nag. 
 Dactylococcus. . 
 
 De Baryanns. Bein. 
 Dasyactis. 
 
 plana. Kutz. 
 Dasygloia. Thiv. . 
 
 amorpha. Thm. . 
 
 DlBMAIIUM. 
 
 turfaceum. Link, 
 DESMIDIE.IE, , . , 
 
 PAGE 
 
 . 38 
 . 138 
 . 90 
 . 97 
 . 139 
 . 140 
 . 137 
 . 123 
 . 295 
 . 160 
 . 142 
 . 276 
 . 256 
 . 124 
 . 172 
 . 175 
 . 135 
 . 180 
 . 135 
 
 91 
 
 79 
 90 
 80 
 90 
 97 
 92 
 77 
 89 
 86 
 90 
 80 
 
 21 
 
 22 
 
 22 
 
 23 
 
 243 
 
 241 
 
 243 
 
 243 
 
 242 
 
 243 
 
 237 
 
 160 
 203 
 
 30 
 296 
 296 
 
 281 
 274 
 274 
 
 278 
 
 74 
 
 Desmonema. B. 
 
 Dillwyni. Berk. . . 
 Dictyosphsezium. Nag. 
 
 constriotum. Ar. . . 
 
 Ehrenbergianum. Nag. 
 
 reniforme. Buln. 
 Dimozphococcus. Br 
 
 Innatus. JBr. , . 
 Diplocolon. 
 
 Heppii. Hzig. . . 
 
 DOLICHOSPERMUM. 
 
 i/noquale. Ralfs . . 
 Bal/sii. Ann. N. H. 
 Smithii. Thw. . , 
 Tliompsoni. Ann. N. H 
 ThwaAtesii. Ealfs. . 
 
 DOTHIDEA. 
 
 anemones. D.C. 
 Dzapaznaldia. Ac/. 
 
 condensata. Hass. , 
 crviciata. Hioks. 
 elongata. Hass. 
 glomerata. Ag. . , 
 nana. Hass. . . 
 plnmosa. Fauoh. 
 
 tenuis. Eng. Fl. 
 Dkilosiphon. 
 
 muscicola. Kutz. 
 
 EOHINELLA. 
 
 articulata. B. Bot. 
 
 ECTOOARPUS. 
 
 aureus. Lyngb. . . 
 chalybeus. Gray. 
 ECTOSPEEMA. 
 
 geminata. Vauch. . 
 hamata. Vauch. 
 ovoidea. Huds. . . 
 terrestris. Vauch. . 
 
 EliISA. 
 
 distorta. Gray. . . 
 
 tnirahilis. Gray. 
 Entezomozpha. Link. 
 
 intestinalis. Linn. 
 
 lacustris. Hass. 
 Ezemosphaeza. D.By. 
 
 viridis. D.By. . . 
 Eudozina. Ehr. . . 
 
 elegans. Ehr. . . 
 
 ElSTULAEIA. 
 
 intestinalis. Grev. 
 Ploeidej, 
 
 GlKAEDlA. 
 
 fusco-pv/rpurea. Gray. 
 Glaeocapsa. Eutz. 
 
 seruginosa. Kutz. . 
 ampla. Kutz. . . 
 arenaria. Babh. 
 atrata. Rabh. . . 
 
 PAGE 
 
 . 276 
 
 . 20 
 
 . 21 
 
 . 20 
 
 . 21 
 
 . 27 
 
 . 27 
 
 . 233 
 
 . 239 
 . 237 
 . 237 
 236 
 . 238 
 
 201 
 191 
 190 
 192 
 189 
 191 
 190 
 193 
 190 
 189 
 
 266 
 
 195 
 
 186 
 
 284 
 
 125 
 126 
 125 
 126 
 
 270 
 
 263 
 
 130 
 
 130 
 
 131 
 
 3 
 
 3 
 
 65 
 
 67 
 
 131 
 
 282 
 
 283 
 204 
 207 
 7 
 207 
 205 
 
320 
 
 INDEX. 
 
 GLiOCAPSA — {continued) 
 
 botryoides. Kntz. . 
 
 caldarioram. Babh. 
 
 coracina. Kutz. 
 
 livida. K'ltz. . . 
 
 magma. Kvtz. . . 
 
 ParoUniana. Men. 
 
 polydeimatica. JSmU, 
 
 qnatemata. Kutz. . 
 
 Balf siana. KuU. 
 
 mpestris. Kutz. 
 
 mpicola. Kid:. . . 
 
 sangninea. Kutz. . 
 
 Shnttleworthiana. Kut 
 Glaeocystis. 
 
 adnata. Na^. 
 
 ampla. Kutz. 
 
 botryoides. Kut:. 
 
 ParoUniana. Men. 
 
 mpestris. Mabh. 
 
 vesiculosa. Nag. 
 Glseothece. Nag. . 
 
 cystifera. SabTi. 
 
 devia. Nag. . . 
 
 granosa. Rahh. . 
 Gloiotiichia. Ag. . 
 
 angiilosa. Ag. 
 
 JBoryana. Kntz. 
 
 gigantea. Rabh. 
 
 natans. T)iw. 
 
 pisnm. TInir. 
 Gomphosphsria. Kutz. 
 
 aponina. Kutz. . 
 Gonatonema. . . 
 
 notabile. Wittr. 
 
 GONATONEilE-E 
 
 Gonium. JIull. . . 
 glaucum. Ehr. . 
 pectorale. Mull. 
 
 H^MATOCOCCUS. 
 
 mniginoius. Hass. 
 Allmanni. Hass. 
 arenarius. Hass. 
 Mnalis. Hass. . 
 Corda. Men. . . 
 cryptophUa. Hass. 
 frustulosus. Hass. 
 granosus. Hass. . 
 Bookerianus. B. & H 
 insignis. Hass- . 
 lividus. Hass. . 
 mucosus. Mocr. 
 murorum. Hass. 
 nivalis. Ag. . . 
 pluvialis. Mot. . 
 rvjpestris. Hass. . 
 sanguineus. A.g. . 
 sanguineus. Harv. 
 theiHaciis. Hass. 
 vulgoAris. Hass, . 
 
 PAGE 
 
 . 8 
 . 206 
 . 205 
 . 205 
 . 207 
 . 8 
 . 206 
 . 206 
 . 200 
 .209 
 . 208 
 . 208 
 . 209 
 
 . 8 
 . 6 
 . 8 
 . 8 
 . 7 
 . 7 
 . 217 
 . 217 
 . 218 
 . 218 
 . 281 
 . 281 
 . 281 
 . 281 
 . 281 
 . 282 
 . 213 
 . 213 
 . 108 
 
 . no 
 
 . 107 
 
 . 69 
 
 . 214 
 
 . 70 
 
 . 207 
 . 10 
 . 207 
 . 204 
 . 51 
 . 10 
 . 30 
 . 218 
 . 9 
 9 
 . 205 
 . 51 
 . 30 
 51 
 . 51 
 7,206 
 . 209 
 . 10 
 . 4 
 . 4 
 
 Hapalosiphon. }fag. 
 
 byssoidens. Kirch. 
 Hassallia. 
 
 byssoidea. Hass. 
 
 compacta. Hass. 
 
 ocellata. Hass. . 
 
 turfosa. Hass. 
 Homaiococcns. Kutz 
 
 Hassallii. Kutz. 
 
 HOHMIDIUM. 
 
 murale. Kntz. . 
 parietinum. Kntz. 
 Hormiscia. J)'e£. . 
 seqnalis. (Kutz.) 
 bioolor (B. B.) . 
 moniliformis. (Kutz. 
 speciosa ( Carm.) 
 zonata. W. & M. 
 
 HOBMOSIPHON. 
 
 ellipsosponim,. Desm, 
 
 inundaium. Kntz. . 
 
 macrosjiorus. Kntz. 
 
 natans. Kntz. . . 
 
 stagnalis. Kutz. 
 Hoxmospora. Breb. . 
 
 mntabilis. Breb. 
 
 ramosa. Thm. . . 
 
 transversalis. Breb. 
 HUMIDA. 
 
 cyanea. Gray. . . 
 
 decortlcans. Gray 
 
 rmiralis. Gray . . 
 Hydriannm. Rabh. . 
 
 heteromorphnm. Rein. 
 Htdrocoleum. 
 
 tTiermale. Kutz. 
 
 tin^:tonum. Br. 
 Htdeodiottej;. . . . 
 Hydrodictyon. Roth. 
 
 utrionlatnm. Roth. 
 Hydraras. Ag. . 
 
 Biicluzelii. Ag. 
 
 fmtidus. Vanch. 
 
 penicellatns. Ag. 
 
 HTDEO G ASTETJSt. 
 
 granulatum. Babh. 
 Inactis. Kutz. . . 
 
 CresswelU. Tliur. 
 
 tinctoria. Thur. . 
 Inodekma. 
 
 lamellosum, Kntz. 
 Isactis. Thur. . . 
 
 plana. Thur. . . 
 Led A. 
 
 capucina. Bory. 
 Lemanea. Bvry. . 
 
 coraUina. Bory. 
 
 Dillenii. Bory. . 
 
 flnviatilis, Ag. , 
 
 PAGE 
 . 274 
 . 274 
 
 . 274 
 . 272 
 . 271 
 . 273 
 . 219 
 . 219 
 
 . 182 
 . 183 
 
 . 178 
 . 180 
 . 181 
 . 179 
 . 181 
 . 179 
 
 . 230 
 . 229 
 . 233 
 . 229 
 . 229 
 . 21 
 . 21 
 . 22 
 . 22 
 
 . 266 
 . 260 
 . 183 
 . 48 
 . 49 
 
 . 255 
 . 257 
 . 35 
 . 35 
 . 38 
 . 24 
 . 25 
 . 25 
 . 25 
 
 . 114 
 . 256 
 . 256 
 . 257 
 
 . 18 
 . 280 
 . 281 
 
 . 107 
 . 294 
 . 294 
 . 298 
 . 294 
 
INDEX. 
 
 321 
 
 Lbmanea — (continued) page 
 
 setacea. Bory 292 
 
 torulosa. Ag 295 
 
 Lemaneace^ 294 
 
 Lkptothkix. 
 
 oohracea. Knfcz. . . . 258 
 
 Lichenoides. 
 
 fungiforme. Ray. . . .114 
 
 LlMNAOTIS. 
 
 dwra. Kutz 279 
 
 LiMNOCHtlDE. 
 
 flos-aqucB. Kutz. . . . 240 
 
 LiNKIA. 
 
 dura. Grev. . . . 279, 282 
 
 LlTHONEMA. 
 
 calcarea. Hasa 279 
 
 crustaceum. Haas. . . , 280 
 
 Iiyngbya. Ag 257 
 
 ceruginosa. Ag 258 
 
 sastnarii. Lieb 258 
 
 ooriam. iAg.") .... 261 
 cris;pa. Jenner .... 181 
 
 curvata, Kabh 258 
 
 floccosa. Hasa 136 
 
 innndafca. (Kutz.) . . . 259 
 litfcoralis. Carm. . . . 258 
 majuscula. Cooks . . . 258 
 
 rmwalis. Ag 182 
 
 oohracea. Thur. . . . 258 
 papyrina. Kirch. . . . 260 
 
 rapestris. Ag 260 
 
 speciosa. Carm. . . . 181 
 Bubfasoa. (Ag.) . . . 262 
 tiirfoaa. (Qarm.) . . . 261 
 
 vulgaris. Kuts 259 
 
 zonata. Hass 179 
 
 Mastigonema. 
 
 plana. Rabh 281 
 
 Mbkettia. 
 
 alpicola. Gray .... 208 
 mucosa. Trev 11 
 
 Bflezismopedia. Meyen. . . 214 
 
 glauoa. Nag 214 
 
 Qoodseri. Hus 215 
 
 punctata. Mey 214 
 
 renis. Babh 215 
 
 ventrionli. Uob 216 
 
 violacea. Kutz 214 
 
 MESOOAKPEiB 101 
 
 MesocairpuB. Hass. . . . 103 
 angustus. Hass. . . . 104 
 depresaua. Sass. . . . 103 
 intricatus. Haaa. . . . 104 
 notabilis, Hasa. . . .110 
 nummuloides. Sass. . . 103 
 
 ovalis. Haaa 103 
 
 parvnlus. Hass. . . . 104 
 plenrooarpus. D.By. . . 105 
 reourvua. Hass. . . . 105 
 soalaris. Kass 104 
 
 MiOEALOA. 
 
 protogenita. Bias. . 
 
 MiOEASTEBIAS. 
 
 falcata. Corda. . . 
 niiczocoleus, Besm. . 
 
 anguiformis. Hasa, 
 
 chthonoplastes. Thur, 
 
 Billwym. Harv. 
 
 gracilis. Hass. . 
 
 marinus, Harv. . 
 
 repens. Hass. 
 
 terrestris. Desm. 
 IHiczocystis. Kutz. 
 
 adnata. Men. 
 
 csruginosa. Kutz, 
 
 angulosa. Kutz. 
 
 atra. Kufe. . . 
 
 atrovirens. Men. 
 
 livida. Men. . . 
 
 macginata. Kirch, 
 
 Parolmiana. Men. 
 
 protogenita. Rabh. 
 
 rupestris. Men. . 
 Kicrospora, Thur. 
 
 bomhycina. Thur. 
 
 floooosa. Thur. . 
 
 fugaoiasima. Ag. 
 
 glomerata. Hass. 
 
 vulgaris. Babh. . 
 nUicrothamnion. Nag, 
 
 vexator. Gke. . 
 Mischococcus. Nag. 
 
 oonfervicola. Nag. 
 
 MONAS. 
 
 prodigiosa. Ehr. 
 
 MONOEMIA. 
 
 intricata. Berk. , 
 
 MONOTKEMA. 
 
 buUosum. Thur. . 
 
 Konostroma. Thur. 
 laoeratum. Thur. 
 Wittrookii. Born. 
 
 Kougeotia. D.By. 
 
 casrulescens. Eng. El, 
 compressa. Eng. El 
 genuflema. Ag. . 
 glutinosa. Hass. 
 glyptosperma. D.By 
 Isovis. Archer, 
 notabilis. Hass. , 
 quad/i'angulatus, Hass, 
 splendens. Kutz, 
 
 MYEIODACTYLOrf. 
 
 endiooefolium. Gray, 
 
 NESTATOGENiE. , . , 
 NeMATOPHYOEjE. . 
 
 Nephzocytium. Nag, 
 Agardhianum. Nag, 
 Naegelii. Grun. 
 
 2y 
 
 . 212 
 
 , 19 
 
 . 254 
 
 , 255 
 
 , 254 
 
 . 276 
 
 , 2.'55 
 
 , 255 
 
 256 
 
 256 
 
 211 
 
 8 
 
 212 
 
 4 
 
 205 
 
 205 
 
 205 
 
 212 
 
 8 
 
 212 
 
 206 
 
 135 
 
 135 
 
 136 
 
 135 
 
 143 
 
 135 
 
 188 
 
 188 
 
 28 
 
 28 
 
 12 
 
 227 
 
 136, 16 
 . 131 
 . 131 
 . 132 
 . 99 
 , 107 
 . 105 
 . 105 
 . 107 
 . 100 
 . 100 
 . 110 
 . 106 
 . 104 
 
 195 
 
 220 
 
 127 
 
 25 
 
 26 
 
 26 
 
322 
 
 INDEX. 
 
 Nodulaxia. Mert. . . 
 
 fluviatilis. Grev. . 
 
 Harreyana. Tlmr. . 
 
 litorea. Thv/r. . . 
 Nostoc. Vauch. . . 
 
 agglutincms. Kutz. . 
 
 arclywm. Kntz. . . 
 
 carneum. Ag. . . 
 
 eoniflonum. B. & Th. 
 
 cocoymelon. Kutz. , 
 
 ctsrulescens. Eabh. 
 
 coernleum. Lyngb. . 
 
 oommune. Yauch. . 
 
 eonfusum. Ag. . . 
 
 ellipsospornm. RaibTi. 
 
 flos-aqua. Lyngb. . 
 
 foUacenm. Ag. .' . 
 
 granulare. Rabh. . 
 
 humifuaum. Carm. 
 
 ichthyon. Eabh. 
 
 intricatum. Men. . 
 
 inunciatum. Kutz. . 
 
 irregulare. Warton. 
 
 Itzigsohnii. Rabh. . 
 
 laeustre. Kutz. . . 
 
 Linokia. S. 4' Th. . 
 
 Uttorale. Kutz. 
 
 maorosporum. Men. 
 
 microsoopicum. Carm, 
 
 musoorum. Ag. , . . 
 
 nivale. Kutz. . . 
 
 sphserionm. Vawih. 
 
 parietinv/m. Kabh. 
 
 peloponnesiaowm, Kutz, 
 
 pisoinale. Kutz. 
 
 piscinale. N. & Witt, 
 
 prismaticum. Ces, 
 
 pruniforme. Ag. 
 
 purpurascens. Kntz 
 
 pyrenaAcum. Rip. 
 
 rvfescens. Ag. 
 
 Tugosum. Kutz. . 
 
 rnpestre. Kut^. , 
 
 sdhmn. Kutz. 
 
 spJuericum. Men. 
 
 spongiseforme. Ag. 
 
 tepidarioi'um. Br. 
 
 variegatum. Haw. 
 
 verrucosum. VaucTi. 
 
 vesicanum. Men. 
 NoSTOCEiE. . . . 
 NoSTOCHINEiE. . . 
 00H10CH«TB. 
 
 hystrix. Thw. 
 (EbOGONIACEjE. . . 
 
 CEdogonium. . . 
 
 aerospornm. B.By, 
 apophysatiim, Br. 
 apophysatvm. Pr. 
 
 PAGE 
 
 . 244 
 . 295 
 . 245 
 . 244 
 . 224 
 . 228 
 . 231 
 . 229 
 . 231 
 . 233 
 . 233 
 . 233 
 . 231 
 . 227 
 . 230 
 . 235 
 . 231 
 . 231 
 . 230 
 . 233 
 . 228 
 . 229 
 . 234 
 . 233 
 . 228 
 . 227 
 . 231 
 . 232 
 . 232 
 . 230 
 . 234 
 . 231 
 . 231 
 . 234 
 . 228 
 . 228 
 . 231 
 . 233 
 . 229 
 . 233 
 . 229 
 . 231 
 . 232 
 . 231 
 . 234 
 . 229 
 . 231 
 . 229 
 . 234 
 . 232 
 . 224 
 . 220 
 
 197 
 148 
 148 
 163 
 162 
 163 
 
 CEdogonium — (contimbed) 
 
 PAGE 
 
 Aroherianum. Ohe. 
 
 157 
 
 Aresohougii. Wittr, . 
 
 159 
 
 Borisianum. Z.Cl. . . 
 
 162 
 
 Bosoii. i.CZ. . . . 
 
 167 
 
 Braunii. Xutz. . . 
 
 161 
 
 calcareum. Cleve. . , 
 
 165 
 
 oapillaoeum. Kutz. . . 
 
 170 
 
 capillare. (Linn.). . . 
 
 165 
 
 oapilliforme. Kutz. 
 
 298 
 
 carbonioum. Wittr. 
 
 166 
 
 oardiaoum. Rass. . , 
 
 166 
 
 ciliatum. (Hass.). 
 
 163 
 
 Cleveanum. Wittr. 
 
 . 164 
 
 compressum. Rabh. 
 
 . 165 
 
 oonoatenatnm. (Rass.), 
 
 163 
 
 orassiusoulum. Wittr. 
 
 . 162 
 
 crassum. {Hass.). . , 
 
 173 
 
 orispnm. {Hass.). . . 
 
 155 
 
 cryptoporum. Wittr. . 
 
 163 
 
 ourvum. -Pr. . . . 
 
 . 154 
 
 cymatosporum. W. S; N, 
 
 154 
 
 delioatulum. Kutz. 
 
 . 169 
 
 depresgum, Prings. 
 
 . 160 
 
 dAplcmi/rum. Jur. . . 
 
 . 159 
 
 eohinospermum. Br. . 
 
 . 164 
 
 ecMnospermum. Pr. 
 
 . 164 
 
 excisum. Wittr. . . 
 
 . 157 
 
 fasoiatnm. Kutz. , . 
 
 . 170 
 
 flavesoens. Mass. . . 
 
 . 160 
 
 gemelliparvm. Haas. . 
 
 . 168 
 
 gemelliparnm. Pr. . . 
 
 . 168 
 
 giganteum. Kutz . . ; 
 
 . 172 
 
 grande. Kutz. . . , 
 
 . 172 
 
 hexagouum. Kutz. . . 
 
 . 170 
 
 Hutohinsise. Wittr. 
 
 . 171 
 
 Itzigsohnii. B.By. 
 
 . 156 
 
 laeustre. Rabh. . . 
 
 . 172 
 
 Landsboronghii. (Hass.). 
 
 168 
 
 Londinense. Wittr. 
 
 . 170 
 
 lougatum. Kutz. . . 
 
 . 171 
 
 macrandum. Wittr. 
 
 . 161 
 
 minus. Wittr. . . . 
 
 . 154 
 
 Nordstedtii. Wittr. . 
 
 . 167 
 
 palndosum. (Eass.). . 
 
 • 156 
 
 Petri. Wittr. . . . 
 
 • 153 
 
 piliferum. Auera. . . 
 
 . 164 
 
 platygynnm. Wittr. . 
 
 . 158 
 
 plnviale. Nord. . . . 
 
 . 159 
 
 princeps. Rass. . . . 
 
 . 171 
 
 Pringsheimianum. Ar. 
 
 . 158 
 
 Pringsheimii. Gram. . 
 
 . 166 
 
 pulchellmn. Br. . . 
 
 . 155 
 
 pulchelhim. Rabh. 
 
 . 166 
 
 puuotafco-striatum. D.Bj 
 
 . 167 
 
 „ var. minor. 
 
 . 154 
 
 regulare. Vaup. . . . 
 
 . 165 
 
 Reinsohii. Boy. . . . 
 
 . 160 
 
 rivniare. L. CI. . . . 
 
 . 169 
 
 rivulare. Rabh. . . . 
 
 . 168 
 
INDEX. 
 
 323 
 
 (EdOgonium — (continued) 
 
 rostellatum. Br. 
 
 Rothii. L. 01. . 
 
 setigerum. Vanp. 
 
 snbsetacenm. Kutx. 
 
 teuellam. KuU. 
 
 tumidalum. Kwtz. 
 
 twmidul/wm. Pr. 
 
 Tindulatnm. Breb. 
 
 nrbioum. Wittr. 
 
 Vauoherii. L. CI. 
 
 Vaucherii. Kabh. 
 
 vernale. (Bass.) . 
 
 vesicatum. Lyngh. 
 Omvia. 
 
 iotryoides. Gray. 
 
 violacea. Gray. . 
 Olpidium. Br. . . 
 
 ampullaoeum. Babh. 
 
 endogennm. Br. 
 Oocystis. Nag. . . 
 
 gigaa. Ar. . . 
 
 sefcigera. Ar. 
 OPHlOCYTlEiE. . . 
 
 Ophiocytium, Nag. 
 
 arbuscula. Br. , 
 
 cochleare, Br. . 
 Oscillaria. Bosc. 
 
 serugescens. Britm. 
 
 alata. Grev. . . 
 
 autliaria. Jurg. , 
 
 o/wbwmnalis. Carm, 
 
 BangU. Carm. , 
 
 chalybea. Mert. . 
 
 cMhonoplastes. E. Fl. 
 
 contexta. Carm, 
 
 coriMm.. Haes. 
 
 decorttcans. Grev. 
 
 Dickiei, Hass. . 
 
 Friesii. Harv. 
 
 Frolichii. Kutn. . 
 
 insignis. Thw. 
 
 irrigna. KuU. 
 
 leptotricha. Xutu, 
 
 limosa. Ag. . . 
 
 Umosa. Hook. , 
 
 UttoraUs. Carm. 
 
 iMCifuga. Hass. . 
 
 rfiucosa. Hass. 
 
 muraUs. Grev. , 
 
 mUBOorum. Ca/rm, 
 
 nigra. Yaihch. 
 
 nigro-viridis. Thw. 
 
 ochracea. Grev. . 
 
 papyrina. Bory. 
 
 parietma. Tauch. 
 
 rabiginosa. Carm. 
 
 rupestrie. Ag. . 
 
 spadicea. Garra. . 
 
 spiralis. Carm. , 
 
 PAGE 
 
 . 155 
 . 158 
 . 162 
 . 173 
 . 169 
 . 168 
 . 156 
 . 160 
 . 156 
 . 155 
 . 166 
 . 155 
 . 172 
 
 . 211 
 . 186 
 . 200 
 . 200 
 . 200 
 . 26 
 . 26 
 . 27 
 
 , 38 
 39 
 38 
 . 246 
 , 248 
 , 267 
 , 250 
 . 259 
 , 263 
 . 253 
 255, 256 
 
 261 
 260 
 254 
 263 
 253 
 253 
 251 
 247 
 251 
 249 
 258 
 262 
 253 
 183 
 250 
 252 
 252 
 259 
 260 
 250 
 248 
 260 
 260 
 247 
 
 Oso I Li A w A — (contimie^ 
 
 splendida. Grev. 
 
 subfusoa. Tauch. 
 
 subuliformis. TJim). 
 
 tenerrima. KiUz. 
 
 tenuis. Ag. , . 
 
 thermalis. Hass, 
 
 turfosa. Carm. 
 
 violacea. Johnst. 
 
 viresoens. Sass, 
 
 viridis. Kutz. 
 Palmella. Lyngi. . 
 
 adnata. Lyngb. . 
 
 ceruginosa, Carm. 
 
 cruenta. Ag. 
 
 cryptopMla, Carm. 
 
 frustulosa. Carm. 
 
 granosa. Berk. . 
 
 hyalina. Breb. . 
 
 Imida. Carm. 
 
 miniata. Nag. 
 
 montana. Ag. 
 
 Mooreana. Harv. 
 
 mucosa. Kutz. . 
 
 ■myosurus. Lyngb. 
 
 nwaUs. Hook. . 
 
 prodigiosa. Mont. 
 
 Ralfsvi. Harv. . 
 
 rwularis. Carm. 
 
 rupestris. Lyngb. 
 
 sanguinea. Ag. . 
 PALMELLACE^. . . 
 
 Palmodictyon. Kutz. 
 
 rnfesoens. Kutz. 
 
 viride. Kutz. . . 
 Pandorina. JShr. . 
 
 elegans. Duj. 
 
 morum. Ehr. 
 Pbdiastee.*;. . . 
 Fediastzum. Mey. 
 
 augnlosnm. Ehr. 
 
 bidentulum. Br. 
 
 bvroMatum. Balfs. 
 
 Boryanmm,. fi. Balfs. 
 
 Boryanum. Ealfs. 
 
 Boryanum. Turp. 
 
 braohylobum. Br. 
 
 eribriforme, Hass. 
 ouspidatum. JBr. 
 constrictum. Ua^s. 
 Ehrenbergii. Br. 
 elegans. Hass. 
 elUpticmn. p. Balfs. 
 elUpticum. Ealfs. 
 esica/vatu/m. Hass. 
 excisum. Br. 
 gracile. Br. . . 
 granulatum. Br. 
 grauulatmn. Balfs. 
 
 var. elathratvm. 43 
 
 PAGD 
 
 . 247 
 . 248 
 . 251 
 . 247 
 . 249 
 . 254 
 . 261 
 . 248 
 . 254 
 . 249 
 . 11 
 . 8 
 . 207 
 . 13 
 . 10 
 . 30 
 . 218 
 . 11 
 . 205 
 . 12 
 . 208 
 12, 218 
 . 11 
 . 25 
 . 54 
 . 12 
 . 209 
 . 210 
 7 
 . 209 
 . 3 
 . 14 
 . 15 
 . 15 
 . 67 
 . 67 
 . 68 
 . 40 
 . 40 
 . 41 
 , 42 
 . 44 
 . 43 
 . 41 
 . 42 
 , 43 
 
 43 
 44 
 42 
 44 
 41 
 42 
 43 
 41 
 44 
 43 
 42 
 42 
 
324 
 
 INDEX. 
 
 Pbdiastkum — I 
 
 hexactis. Hass, 
 
 Jieptaetis. Hass. 
 
 heptactis. Ealfs. 
 
 incisum. Hass. . 
 
 lunare. Hass. 
 
 Napoleonis. Hass. 
 
 Napoleonis. Ealfs. 
 
 pertasuia. Kutz. 
 
 rotula. E7ir. . . 
 
 selenaea. Kutz. . 
 
 selentea. Pritoh . 
 
 simplex. Hass. . 
 
 simplex. Ralfs. . 
 
 tet/ras. Ealfs. . . 
 
 tricyclum. Hass. 
 
 trnncatum. Br. . 
 Petalonema. Berk. 
 
 alatum. Be7'lc. 
 Petrouema. 7/m. 
 
 frutioulosum. Thio. 
 Phokmidium. 
 
 corium. Ag. . . 
 
 immdatum. Kutz. 
 
 papyraceum. Eabh. 
 
 papyrinum. Kutz. 
 
 rupestre. Kutz. . 
 
 subfuscum. Kabh. 
 
 vulgare. Kutz. 
 PHTCASTBrM. 
 
 longispirmm. Perty, 
 Phycocheomophycb^ 
 Phyllactidium. 
 
 pule/iellum. Kutz. 
 
 setigericm. Kutz. 
 Physaotes. 
 
 pisum. Kutz. 
 Fithophora. Witii: 
 
 Kewensis. Wittr. 
 PiTHOPHORACEiB. . 
 
 Flectonema. Thur. 
 
 Kirohneri. C/ie. 
 
 miraiile. Kirch. 
 
 mirabile. Thur. . 
 Pleukocaepus. 
 
 compressus. Rabh. 
 
 mirabilis. Br. 
 Pleurococcus. Men. 
 
 angalosus. Men. . 
 
 Beigelli. K. <t- B. 
 
 bituminosus. Men. 
 
 eohcBrens. Breb. 
 
 miniatus. Nag. . 
 
 (?) mucosuB. Rabh. 
 
 roseo-persicinus. Rabh. 
 
 luperbus. Cien. . 
 
 vestitus. Rein. . 
 
 vulgaris. Men. . 
 Polycystis. 
 
 (ETuginosa, Kutz. 
 
 PAGE 
 
 . 42 
 45 
 . 44 
 . 45 
 41 
 . 44 
 41, 42, 43 
 . 43 
 . 45 
 . 41 
 . 43 
 . 44 
 42,43 
 . 44 
 . 44 
 . 44 
 . 267 
 . 267 
 
 . 275 
 
 261 
 259 
 260 
 260 
 260 
 262 
 259 
 
 32 
 203 
 
 197 
 196 
 
 282 
 146 
 147 
 146 
 263 
 264 
 264 
 263 
 
 105 
 
 105 
 
 3 
 
 4 
 
 4 
 
 296 
 
 204 
 
 6 
 
 4 
 
 6 
 
 7 
 
 296 
 
 3 
 
 212 
 
 
 PAGE 
 
 POLYEDRIB.ffii. . . . 
 
 . 31 
 
 Polyedrium.ffaj. . . 
 
 . 31 
 
 enorme. Rabh. . . 
 
 . 32 
 
 gigas. Wittr. . . 
 
 . 31 
 
 longispinnm. Rabh. 
 
 . 32 
 
 tetraedrioum. Nag. 
 
 . 32 
 
 POEPHYBACEjB. . . . 
 
 . 282 
 
 Pxasiola. Ag. ... 
 
 . 128 
 
 oalophylla. Spr. . . 
 
 . 130 
 
 crispa. Kutz. . . 
 
 . 128 
 
 farfuraoea. Men. . 
 
 . 129 
 
 stipitata. Suhr. 
 
 129 
 
 Fozphyzidium. . . 
 
 . 13 
 
 cruentum. Nag. . . 
 
 . 13 
 
 Pkasiolb^ 
 
 . 128 
 
 Prolifbra. 
 
 
 Borisiana. L.Cl. . . 
 
 . 162 
 
 Boscii. L.Cl.. . . 
 
 . 168 
 
 rivularis. L.Cl. . . 
 
 . 169 
 
 Rothii. L.Cl. . . . 
 
 . . 159 
 
 VaucheHi. L.Cl. . . 
 
 . 156 
 
 PROTOCOCCACByB. . . 
 
 . 29 
 
 Protococce^. . . 
 
 . 29 
 
 Pzotococcus. . . . 
 
 . 29 
 
 angulosus. Ca. . . 
 
 . 4 
 
 cohoerens. Kutz. 
 
 . 201 
 
 communis. Kutz. . 
 
 . 4 
 
 crustaceus. Kutz. . 
 
 . 297 
 
 gigas. Kutz. . . . 
 
 . 31 
 
 magma. Men. . . 
 
 . 208 
 
 monospermus. Corda 
 
 . 51 
 
 mucosus. Kutz. . . . 
 
 . 4 
 
 nivalis. Ag. . . . 
 
 . 54 
 
 palustris Kutz. . . 
 
 . 4 
 
 pkiviahs. Kutz. . . 
 
 . 51 
 
 roseo-per^ioinus. Kutz 
 
 . 6 
 
 targidMS. Kutz. . . 
 
 . 204 
 
 umbrinUfS. Kutz. 
 
 . 297 
 
 viridis. Ag. . . . 
 
 . 29 
 
 vulgaris. Kutz. ., . 
 
 . 4 
 
 Rhaphidium. Kutz. . 
 
 . 19 
 
 aoioulare. Br. . . 
 
 . 19 
 
 duplex. Kutz. . . 
 
 . 20 
 
 falcatum. Corda. 
 
 . 19 
 
 polymorphvmi. Rabh. 
 
 . 19 
 
 triplex. Rabh. . . 
 
 . 20 
 
 Rhizoclonium. Kutz. 
 
 . 140 
 
 Casparyi. Hat-y. . . 
 
 . 140 
 
 flavioans. Jurg. . . 
 
 . 141 
 
 Rhizonema. 
 
 
 interi-uptum. Thw. . 
 
 . 266 
 
 Rhizophydium. Sch, 
 
 . 199 
 
 Barkerianum. Ar. . 
 
 . 199 
 
 Ehodophycb^. . . . 
 
 . 282 
 
 Ehynchonbma. 
 
 
 abbreviatum. Kutz. 
 
 . . 93 
 
 affime. Kutz. . . . 
 
 . 93 
 
 angulare. Kutz. . . 
 
 . 92 
 
 diduotum. Kutz. 
 
 . . 96 
 
INDEX. 
 
 325 
 
 Rhynohonema— (coTOMm«e(J) 
 
 PAGE 
 
 duhi/iim. Kutz. . . 
 
 97 
 
 galUcum. Ripart. . . 
 
 94 
 
 Jennen. Kutz. . 
 
 97 
 
 malleolus. Kntz. . . 
 
 93 
 
 minimum. Kutz. . . 
 
 96 
 
 quadrata. Kutz. . . . 
 
 95 
 
 reversum. Kutz. . . . 
 
 92 
 
 rostratvm,. Kutz. . . 
 
 88 
 
 Woodsii. Kutz. . . . 
 
 91 
 
 Rivulazia, Roth. . . . 
 
 27T 
 
 angulosa. Kutz. . . . 
 
 281 
 
 botryoides. Carm. 
 
 280 
 
 calcarea. E. Bot. . . 
 
 279 
 
 Crustacea. Garm. . . 
 
 280 
 
 dura. Kute 
 
 279 
 
 echinata. E. Bot. . . 
 
 278 
 
 elegans. E. Bot. . . . 
 
 194 
 
 ■gigantea. Fisoh 
 
 281 
 
 granalifera. Oarm. . . 
 
 280 
 
 incrassata. Pnrt. . . 
 
 195 
 
 Linhia. Roth. . . . 
 
 227 
 
 natans. Gray 
 
 281 
 
 pisum. Ag 
 
 2S2 
 
 plana. Harv. . . . 
 
 281 
 
 pruniformis. Pnrt. . . . 
 
 281 
 
 radians. Kirch 
 
 279 
 
 ■tuberculosa. B. Bot. . . 
 
 194 
 
 tuiulosa. D.O. . . . 
 
 16 
 
 Saeoina. 
 
 
 renis. Hepw 
 
 215 
 
 ventri'cuXi. Good. . . . 
 
 215 
 
 SOENBDESMEiE 
 
 32 
 
 Scenedesmus. Mey. . . . 
 
 33 
 
 aoutns. 3Iey 
 
 33 
 
 antennatus. Brei. . . . 
 
 34 
 
 dimorphus. Ralfs. , 
 
 35 
 
 drnpleo). Ralfa 
 
 20 
 
 oUiquus. Ralfs. . . . 
 
 34 
 
 obfcasua. Mey 
 
 33 
 
 quadrieauda. Breb. . . 
 
 34 
 
 quadricoMdatus. Ralfs. 
 
 35 
 
 triseriabus. Ralfs. . . . 
 
 34 
 
 Schizochlamys. Br. . . . 
 
 10 
 
 gelatinosa. Br. . . . 
 
 11 
 
 Schizogoni-um. Kutui . . 
 
 183 
 
 rnurale. Kutz 
 
 184 
 
 SCHIZOSIPHON. 
 
 
 cataraetce. Nag.' . . . 
 
 276 
 
 Sciadium. £r 
 
 39 
 
 arbuscula. Sr 
 
 39 
 
 Scytonema. Ag 
 
 264 
 
 Scmgii. Lyngb 
 
 263 
 
 iyssoideum. Harv. . . . 
 
 274 
 
 ciuereum. Mtn. . . . 
 
 265 
 
 cirrhosum. Berk. 
 
 276 
 
 cirrhosum. Carm. . . . 
 
 270 
 
 "ompachMi. Eng. F]. . . 
 
 272 
 
 crusto/Ceum. Ag. . . . 
 
 275 
 
 Eoffmanm. Ag 
 
 267 
 
 S0YT0NUMA.—(00Htimied) 
 
 PAGE 
 
 interruptum. Thiu. 
 
 . . 266 
 
 Julianum. N. & Witt. 
 
 . . 266 
 
 minutum. Harv. 
 
 . . 273 
 
 myochrouS. Ag.. 
 
 . . 265 
 
 natans. Breb. . . 
 
 . . 265 
 
 ocellatum. Harv. 
 
 . . 271 
 
 panrUforme. Ag. 
 
 . . 272 
 
 turfaceum. E. Bot. 
 
 . . 273 
 
 SCTTONBMBiE. . . . 
 
 . . 264 
 
 SCTTOSIPHON. 
 
 
 intestinalis. Gray. . 
 
 . . 131 
 
 Selenastzum. Bein. . 
 
 . . 47 
 
 Bibraianum. Bein. 
 
 . 47 
 
 Septoeia. 
 
 
 anemones. Eokl. 
 
 . 201 
 
 Seepbntaeia. 
 
 
 compressa. Gray. . 
 
 . 105 
 
 genuflexa. Gray. 
 
 . 105 
 
 SlPHOPHYCE^ . . . 
 
 . Ill 
 
 Siiogonium. Kutz. 
 
 . 97 
 
 Braunii. Kntz. . . 
 
 . 97 
 
 hreviarticulaium. Kutz 
 
 . . 97 
 
 stioticum. Kutz. 
 
 . 97 
 
 SiBOSIPHON. 
 
 
 Bouteillii. Breb. 
 
 . 271 
 
 compactus. Kutz. 
 
 . 272 
 
 ocellatus. Kutz. 
 
 . 271 
 
 panniformis. Kutz. 
 
 . 272 
 
 pulwinaUiS. Breb. . 
 
 . 273 
 
 saxicola. Johns. 
 
 . 273 
 
 truncicola. Rabh. . 
 
 . 274 
 
 SOEASTEE.a! 
 
 . 45 
 
 Sozastzum. Kutz. . . 
 
 . 46 
 
 spinulosum. Nag. . . 
 SOBOSPOEA. 
 
 . 46 
 
 grumosa. Haas. . . . 
 
 . 12 
 
 montana. Hass. . . 
 
 . 208 
 
 Balfsii. Hasa. . . . 
 
 . 209 
 
 vireseens. Haaa. . . 
 
 . 210 
 
 Speemosiea. 
 
 
 Barveyana. Thw. . 
 
 . 245 
 
 litorea. Kntz. . . 
 
 . 244 
 
 Sph^eooakpus. 
 
 
 augustus. Haas. , . . 
 
 . 104 
 
 depressus. Haas. . . 
 
 . 103 
 
 intricatus. Hass. . . 
 
 . 104 
 
 nummuloides. Haas. . 
 
 . 103 
 
 ovalis. Hass 
 
 . 103 
 
 parvulus. Hass. . . . 
 
 . 104 
 
 recurvus. Hass. . . . 
 
 . 105 
 
 SPHiEKONEMA. 
 
 
 anemones. Lib. . . . 
 
 . 201 
 
 Spheezoplea. Ag. . . . 
 
 . 132 
 
 annnlina. Ag. . . . 
 
 . 134 
 
 crispa. Berk. . . 
 
 . 181 
 
 SPHiEKOPLEACEiB. . . 
 
 . 132 
 
 Sph^eosiea. 
 
 
 vohom, Ehr 
 
 . 64 
 
326 
 
 tNDEX. 
 
 Sphaezozyga. Ag. . 
 
 Berkeleyana. ITiw. 
 
 Broomei. Thw. . 
 
 CarmicliaeU. Harv. 
 
 elastica. Balfs. . 
 
 fios-aqua. Babh. 
 
 SassalUi. Babh. 
 
 incBqualis. Kntz. 
 
 Jacobi. Balfs. 
 
 leptosperma. Ralfi. 
 
 Mooreana. Balfs. 
 
 oscillarioides. Kiitz, 
 
 BcUfsii. Babh. 
 
 Thwaitesii. Harv. 
 
 variahiUs. Kutz. 
 SPIKILLrai. 
 
 Jenneri. Hass. . 
 
 minutisHmuTn. Hass. 
 
 rupestre. Hass. 
 Spizogyza. Link. 
 
 affinis. Petit. 
 
 altemata. Kntz. 
 
 arota. Kutz. . . 
 
 BravMU. Babh. 
 
 bellis. Bass. . . 
 
 calospora. Cleve. 
 
 oaierueformis, !Kiitz, 
 
 com/muTiis. Kntz. 
 
 csondensata. Tauch, 
 
 crassa. Kutz. 
 
 dedmina. Kutz. 
 
 flavicans. Kutz. 
 
 flavescens. 3ass. 
 
 Fleehsigii. Babh. 
 
 gastroides. Kntz. 
 
 gracilis. Kntz. . 
 
 Hantschii. Babh. 
 
 SassalUi. Petit. 
 
 Meeriana. Kntz. 
 
 vnHata. Kntz. 
 
 inflata. Babh. 
 
 incegualis. Kntz. 
 
 insignis. Hass. . 
 
 jngalis. Dillw. . 
 
 Ia33a. Kntz. . , 
 
 longata. Vauch. 
 
 major. Kntz. 
 
 majuscula. Kntz. 
 
 mvrdbiUs. Kntz. 
 
 NcegeUi. Kntz. . 
 
 nitida. DilVw. 
 
 nodosa. Kntz. 
 
 orbicniaris. Hass. 
 
 orthospira. Nag. 
 
 parva. Kntz. . . 
 
 porticalis. Petit. 
 
 porticalis. Vauch. 
 
 protecta. Wood. 
 
 pnnceps. Cleve. 
 
 qnadiata, Peblt. 
 
 PAGE 
 
 . 240 
 . 241 
 . 241 
 . 240 
 . 243 
 . 240 
 . 236 
 . 239 
 . 242 
 . 242 
 . 242 
 . 238 
 . 237 
 . 236 
 . 236 
 
 . 245 
 . 246 
 . 247 
 . 83 
 . 93 
 . 88 
 . 91 
 . 94 
 . 88 
 . 94 
 . 93 
 . 92 
 .. 91 
 . 85 
 . 90 
 . 90 
 . 93 
 . 91 
 . 96 
 
 93 
 . 94 
 . 94 
 . 85 
 
 91 
 . 97 
 . 96 
 . 94 
 . 86 
 . 90 
 . 92 
 . 90 
 . 87 
 . 92 
 . 96 
 . 86 
 . 91 
 
 87 
 . 87 
 . 93 
 . 90 
 . 89 
 . 95 
 . 86 
 . 95 
 
 Spikogyea — (continued) 
 
 quinina. Kntz. 
 
 rimilaris. Babh. 
 
 seiiformis. Kntz. 
 
 setiformis. Petit. 
 
 suhcequa. Kntz. 
 
 mbtilis. Kntz. . 
 
 tennissima. Harv. 
 
 torulosa. Kntz. . 
 
 turpis. Kntz. 
 
 ulotrichoides. Kntz. 
 
 varians. Kntz. . 
 
 velata. Nordst. . 
 
 ventricosa. Kntz. 
 
 Weberi. Kutz. . 
 
 Weberi. Babh. . 
 Spizulina. Link. . 
 
 hrevis. Kntz. . . 
 
 Jenneri. Kutz. . 
 
 oscillarioides. Turp 
 
 rupestre. Babh. . 
 
 tennissima. Kutz. 
 STAtTEASTBUM. 
 
 enorme. Ralfs. . 
 
 falcatwm. Ehr. . 
 STATJROCABPtrS. 
 
 affiiiis. Hass. 
 
 capueinus. Hass. 
 
 ccerulescens. Hass. 
 
 graciUs. Hass. 
 gracillimus. Hass. 
 quadrangulatus. 
 quadratus. Hass. 
 virescens. Hass. 
 
 Stauzogenia. Kutz. 
 
 rectangnlaris. Br. 
 Stauzospezmum . Kutz. 
 
 capucinum. Kutz. 
 
 franconicum. Bein. 
 
 gracillimnm. Hass. 
 
 notabiU. Babh. . 
 
 qnadratnm. D. By, 
 
 viride. Kutz. . 
 Stephanosphaeza. Cohn. 
 
 plnvialis. Oohn. 
 Stigeoclonium. Kutz. 
 
 fastigiatnm. (Rolfs, 
 
 nanum. (Dillw.) . 
 
 protensnm. (Dillw), 
 
 tenne. Ag. . , 
 
 thermale. Br. , 
 
 Stigonema. Ag. . 
 Bonteillii. (Breb.) 
 compactnm. (Kirch.) 
 interruptum. Hass. 
 mamillosnm. Ag. 
 minntniu. Hass. 
 ooeUatnm. Thur. 
 panniforme. Kirch, 
 
 Haas. 
 
 PAGE 
 
 . 90 
 . 90 
 . 88 
 . 86 
 . 88 
 . 92 
 . 96 
 . 92 
 . 93 
 . 91 
 . 91 
 . 297 
 . 96 
 . 95 
 . 96 
 . 245 
 . 246 
 . 245 
 . 246 
 . 247 
 . 246 
 
 32 
 19 
 
 107 
 107 
 107 
 107 
 107 
 106 
 106 
 106 
 107 
 46 
 46 
 106 
 107 
 107 
 106 
 110 
 106 
 107 
 71 
 71 
 188 
 191 
 190 
 190 
 189 
 189 
 270 
 271 
 272 
 266 
 272 
 273 
 271 
 271 
 
INDEX. 
 
 327 
 
 SiiGOTSBiix—^eontimted) 
 
 PAGE 
 
 Teentepohlia — {contimieeC) page 
 
 saxioolum. Nag. . . 
 
 . 273 
 
 ioUthus. Wallr. . . . 
 
 186 
 
 tnrfaoeum. £erk. . . 
 
 . 272 
 
 pulchella. B. Fl. . . . 
 
 284 
 
 Supplement 
 
 . 276 
 
 palehella. Hass. . . . 
 
 284 
 
 Symphyosiphon. Kutz. 
 
 . 267 
 
 Teichiphoebsi 
 
 275 
 
 Hofimanni. Eutz. . . 
 
 . 267 
 
 Teichoemus. 
 
 
 Symploca. Eutz. . . . 
 
 . 262 
 
 imcv/rvus. All 
 
 235 
 
 luoifuga. Earv. . 
 
 . 262 
 
 oscillarioides. Kalfs. . . 
 
 238 
 
 Ealfsiana. Eufz. . 
 
 . 263 
 
 rectus. Ealfs 
 
 236 
 
 Synchitxium. B.By . 
 
 . 200 
 
 spiralis. Ealfs 
 
 235 
 
 anemones. Woron. 
 
 . 201 
 
 ThwaitesU. Ealfs. . . . 
 
 236 
 
 merourialis. Fokl. 
 
 . 201 
 
 Tyndaeidea. 
 
 
 Taraxaoi. D.Sy. . 
 
 . 201 
 
 dbhreviafa. Hass. . . . 
 
 81 
 
 Synechococcus. Nag. 
 
 . 217 
 
 anomala. Hass. . . 
 
 81 
 
 orasans. Ar. . . 
 
 . 217 
 
 iicolor. E. Bot. . . 
 
 181 
 
 Tetzapedia. Bern. 
 
 . 215 
 
 liornis. Hass 
 
 80 
 
 Crax-Miohaeli. 'Rein. 
 
 . 216 
 
 coHspicua. Hass. . . . 
 
 77 
 
 EeiQSohiana. Ar. . 
 
 . 216 
 
 cruciata. Hary. . . . 
 
 81 
 
 setigera. Ar. . . 
 
 . 216 
 
 cruciata. Hass. . . . 
 
 79 
 
 Tetzaspoza. Link. . 
 
 . 15 
 
 decussata. Hass. . . . 
 
 77 
 
 bnllosa. Ag. . . . 
 
 . 16 
 
 immersa. Hass. . . . 
 
 77 
 
 flava. Hass. . . . 
 
 . 16 
 
 insignis. Hass. . . . 
 
 83 
 
 gelatinosa. VoMch. 
 
 . 16 
 
 interposita. Hass. . . . 
 
 80 
 
 lubrioa. Motk. . . 
 
 . 16 
 
 lutescens. Hass. . . . 
 
 81 
 
 minima. DesT. . . 
 
 . 16 
 
 ovalis. Hass. . . 
 
 80 
 
 Tetbaspoeella. 
 
 
 peetinata. Eng. Fl. . 
 
 77 
 
 iMbrica. Gain. . 
 
 . 16 
 
 Balfsii. Hass 
 
 78 
 
 Thozea. Bory. . . . 
 
 . 293 
 
 stagnalis. Hass. . . . 
 
 81 
 
 ramosissima. Sory. 
 
 . 293 
 
 stagrvicola. Hass. • . 
 
 81 
 
 Thwaitesia. 
 
 
 stelUna. Jenn. . . . 
 
 80 
 
 Burieei. Mont. . . 
 
 . 80 
 
 Vlotbicix.. Eutz 
 
 181 
 
 Tolypothzix. Ewtz. . 
 
 . 268 
 
 wqualis. Kntz. . . . 
 
 180 
 
 segagropila. Eute. . 
 
 . 269 
 
 iicolor. Ealfs. . . . 
 
 181 
 
 oirrhosa. {Oarm.) . 
 
 . 270 
 
 catenceformis. Kutz. . 
 
 180 
 
 ooaotilis. Eutz. 
 
 . . 269 
 
 crispa. Kntz 
 
 181 
 
 DUhvyni. Harv. 
 
 . . 276 
 
 moniliformis. Kutz. . 
 
 179 
 
 distorta. Hass. 
 
 . . 269 
 
 parietina. (Yauch.} 
 
 • 183 
 
 distorta. Eutz. 
 
 . . 268 
 
 radioans. Eutz. . . . 
 
 182 
 
 flaooida. Eutz. . . 
 
 . .268 
 
 _«pe(!icaai.JKutz. . . . 
 
 181 
 
 muscicola. Kntz. . 
 
 . 269 
 
 sulUUs. Kirch. . . . 
 
 182 
 
 jmnctata. Hase. 
 
 . 269 
 
 tenerrima. Eutz. '. . 
 
 182 
 
 pygmcsa. Kutz. . 
 
 . 269 
 
 tenuis. Eutz 
 
 . 182 
 
 TOBULA. 
 
 
 variabilis. Eutz. . . 
 
 . 182 
 
 mesomela. Carm. . 
 
 . . 187 
 
 zonata, Kutz. . . . 
 
 179 
 
 Tkbmella. 
 
 
 TTLOTEICHEiE 
 
 178 
 
 adv^ta. Hnds. . . 
 
 . . 8 
 
 Ulva. 
 
 
 crispa. With. . . 
 
 . . 128 
 
 bullosa. Eoth. . . . 
 
 16 
 
 cruenta. Bng. Bot. 
 
 . . 13 
 
 calo'phylla. Hass. . . 
 
 . 130 
 
 Dama com/u/u/m. Dill. 
 
 . . 195 
 
 crispa. Hass 
 
 . 128 
 
 granulata. Hnds. . 
 
 . . 114 
 
 furfuraoea. Grev. . . 
 
 . 129 
 
 marina. Dillen. 
 
 . . 130 
 
 gelatinosa. Tauoh. . . 
 
 • 16 
 
 mhoMs. Brown. . . 
 
 . . 54 
 
 grarmlaia. Light. . . 
 
 . 114 
 
 noitoc. Linn. . . 
 
 . . 231 
 
 incrassata. E.Bot. . . 
 
 . 195 
 
 pahiStris. Dillen. . 
 
 . . 114 
 
 intestinalis. Huds. . . 
 
 . 130 
 
 virioulata. Huds. . 
 
 . . 281 
 
 lactuca. J. Huds. . . 
 
 . 128 
 
 verrucosa. Huds. . 
 
 . . 234 
 
 hibrica. Eoth. . . . 
 
 . 16 
 
 Teentepohlia. 
 
 
 marina. Bay. . . . 
 
 . 130 
 
 aureus. Ag. . . . 
 
 . . 186 
 
 montana. Lightf. . . 
 
 . 208 
 
 chaVyhea. Johnsfc. . 
 
 . . 284 
 
 pisiformis. Huds. . 19^ 
 
 1,232 
 
 eorymbifera. E. Bot. 
 
 . .284 
 
 prtmi/ormis. Huds. . 
 
 . 233 
 
328 
 
 Ulva — (eotUitmei) 
 
 terrestrii. Gray. 
 UlTACEi. . 
 
 J5j,t£m 
 
 Ukkdo. 
 
 nivalis. Baner. 
 Vrococcus. Boss. 
 
 AllTTiaTini 3ass. 
 
 cryptophylns. Hass. 
 
 Hookerianns. Sass. 
 
 inBignis. Hass. 
 Vaginaria. 
 
 chthonoplastes. Grev. 
 
 vulgaris. Gray. . 
 Vauchexia. B.C. . 
 
 aversa. Bass. 
 
 circiiiata. Kntz. 
 
 clavata. Vanch. . 
 
 caspitosa. Yanch. 
 
 dichotoma. Lyngb. 
 
 Dillwyni. Ag. 
 
 Dillwyni. Babh. 
 
 geminata. Walz. 
 
 gloUfera. D.By. . 
 
 gramilata. Grev. 
 
 hamata. Walz. , 
 
 hamulata. Kntz. 
 
 multicapsularis. Harv. 
 
 omithocephala. Ag. 
 
 ornithocephala. Hass 
 
 orata. Gray. . . 
 
 ovoidea. Hass. . 
 
 pacTiy derma. Walz. 
 
 polysperma. Hass. 
 
 racemosa. Harv. 
 
 racemosa. Sabb, 
 
 radicata. Hook. . 
 
 repens. Hass. . . 
 
 rostellata. Kntz. . 
 
 saXina. Kntz. . . 
 
 sericea. Lyngh. , 
 
 sessilis. Touch. . 
 
 spTuBrocarpa. Kutz, 
 
 submarina. Berk. 
 
 terrestris. Lyngb. 
 
 Ungeri. Thnr. 
 Vavcheeiace^.. . . 
 Vesiculifeea. 
 
 aquale. Hass. 
 
 affimis. Hass. . . 
 
 alata. Hass. . . 
 
 Boscii. Hass. . . 
 Candollei. Hass. 
 
 capillaris. Hass. 
 
 cardiaca. Hass. . 
 
 ciliata. Hass. 
 
 compressa. Hass. 
 
 concatenaia. Hass. 
 
 condensata. Hass. 
 
 crassa. Hass. . . 
 
 PAGE 
 
 . 128 
 . 128 
 . 130 
 
 54 
 
 9 
 
 10 
 
 10 
 
 9 
 
 . 256 
 . 256 
 . 116 
 . 121 
 . 126 
 . 123 
 . 123 
 . 120 
 . 122 
 . 125 
 . 125 
 . 120 
 . 114 
 . 126 
 . 126 
 . 114 
 . 121 
 . 124 
 . 125 
 
 125 
 . 122 
 
 121 
 . 125 
 . 123 
 . 114 
 . 124 
 . 121 
 . 120 
 . 121 
 . 123 
 . 123 
 . 120 
 . 126 
 123, 122 
 . 115 
 
 . 160 
 . 152 
 . 152 
 . 168 
 . 155 
 . 171 
 . 166 
 . 164 
 . 165 
 . 163 
 . 152 
 . 173 
 
 VESicuHFEBi — (continued) 
 
 cnspa. 
 
 Curieri. Hass. 
 
 dissiliens. Hass. 
 
 dubia. Hass. . 
 
 elegwns. Hass. . 
 
 fasciata. Hass. 
 
 fiavescens. Hass. 
 
 hexagona. Hass. 
 
 iniequalis. Hass. 
 
 la&nstris, Hass. 
 
 Zandsboroughii. Hass, 
 
 Mulleri. Hass. . 
 
 ovata. Hass. . . 
 
 paludosa. Hass. . 
 
 princeps. Hass. . 
 
 pvlchella. Hass. 
 
 Balfsii. Hass. . 
 
 IU>thii. Hass. 
 
 sphcerica. Hass. . 
 
 Taucheri. Hass. . 
 
 xernalis. Hass. . 
 
 virescens. Hass. . 
 VoLVOCiXEj; . . . 
 Volvos. Linn. . . 
 
 aureus, Ehr. . . 
 
 globatoT. L. . . 
 
 minor. Stein. 
 
 steBatvs. Ehr. 
 
 ZONOTEICHIA. 
 
 calcarea. Babh. . 
 
 ZOOGAiACTIXA. 
 
 imetropha. Sette. 
 Zygnema. Eictz. 
 
 aVbreviatum. Hass. 
 cestinim. Hass. . 
 affine. Hass. . . 
 aUematum. Hass. 
 angulare. Hass. . 
 angnlatum. Hass. 
 anomalnm. Hass. 
 tella. Hass. . ■ 
 Mpunctatiim. Grev. 
 hipimctatum. Jolmst, 
 commune. ~~ 
 compressum. Lyngb, 
 cruciatum. Vauch. 
 cttrvatum. Ag, 
 deciminum. ~ 
 didiKtum. Hass. 
 Dillvryni. Kutz. 
 dubiwm. Hass. . 
 fiavescens. Hass. 
 gemiflexum. Johnst. 
 gracile. Berk, 
 gracile. Hass. 
 Grevilleanum. Hass, 
 Bassallii. Hass. 
 incequale. Hass. 
 infiatum. Eng. Bet. 
 
 PAGE 
 
 . 155 
 . 152 
 . 152 
 . 152 
 . 168 
 . 170 
 . 161 
 . 170 
 . 152 
 . 172 
 . 168 
 . 152 
 . 169 
 . 156 
 . 171 
 . 166 
 . 152 
 . 159 
 . 152 
 . 156 
 . 155 
 . 153 
 . 50 
 . 56 
 . 64 
 . 63 
 . 64 
 . 64 
 
 279 
 
 12 
 
 76 
 
 92 
 
 92 
 
 93 
 
 88 
 
 92 
 
 , 92 
 
 81 
 
 88 
 
 77 
 
 79 
 
 92 
 
 , 105 
 
 79 
 
 97 
 
 9o 
 
 . 96 
 
 79 
 
 . 97 
 
 . 93 
 
 . 105 
 
 . 99 
 
 , 93 
 
 . 96 
 
 . 94 
 
 . 95 
 
 . 90 
 
INDEX. 
 
 329 
 
 Zygnema. — (oontinued) 
 inflatum. Haas. . . 
 insigne. Hass. . . 
 ineigne. KuU. . . 
 mtermedivm,. Haes. 
 mterrvptum. Hass. 
 Jermeri. Hass. . . 
 leiospermum. D. By 
 longatv/m. Hasa. 
 malformatvm, Hass, 
 maXleolmn. Hass. 
 maxmmn. Hass. 
 minvmv/m. Hass. 
 mirdbile. Hass, . 
 negleotum. Hass. 
 nitidwm. Lyngb. 
 orbioulare. Hasa. 
 ordmari/um. B. . 
 parvnlum. Kute. 
 pa/rimm. Hass. . 
 pectinatum. Ag. 
 guad/ratwm. Hass, 
 qwitvin'wm. Hass. 
 Balfsii. Kwtz. 
 reversv/m. Hass. 
 rmula/re. Hass. . 
 rostratum. Hass. 
 serraimm. Hass. 
 
 PAGE 
 
 . 97 
 . 94 
 . 83 
 . 95 
 . 88 
 . 97 
 
 96 
 92 
 93 
 88 
 96 
 92 
 89 
 85 
 88 
 78 
 78 
 93 
 77 
 95 
 89 
 78 
 92 
 90 
 87 
 85 
 
 Z V GNEM A— (continued) 
 
 PAGE 
 
 sjnralis. Eng. Bot. 
 
 . 90 
 
 stelliuam. Vauch. . 
 
 . 80 
 
 subventricosvm,, Hass. 
 
 . 96 
 
 tenue. Rabh. . . 
 
 . 83 
 
 tennissimum. Hass. 
 
 . 96 
 
 varians. Hass. . . 
 
 . 91 
 
 Vauoherii. Ag. . . 
 
 . 80 
 
 ventricosum. Hass. 
 
 . 96 
 
 Woodsii. Hass. . . 
 
 . 91 
 
 Zygnemaoe^. . . . 
 
 . 74 
 
 Zygneme^ .... 
 
 . 76 
 
 Zygogonium. Eutz. . 
 
 . 98 
 
 Agardhii. Rabh. 
 
 . 99 
 
 conspieuum. Kutz. . 
 
 . 77 
 
 decussaimn. Kutz. . 
 
 . 77 
 
 didymmn. Kabh. . 
 
 . 99 
 
 erioetorum. D.By. 
 
 . 98 
 
 gracile. Berk. . . 
 
 99 
 
 immersum. Kutz. . 
 
 . 77 
 
 loeve. Kutz. . . . 
 
 . 100 
 
 parvulum, Kutz. 
 
 . 78 
 
 pectinatum. Eabh. 
 
 . 77 
 
 plev/rospermum. Kutz. 
 
 . 105 
 
 BalfsU. Kutz. . . 
 
 . 78 
 
 torulosum. Kutz. 
 
 . 98 
 
 Zygophyoe^. . . . 
 
 . 74