i-"7.'>...ui M'A, I ) Albert R.. Mann Libkary Cornell University Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924090245576 DEPARTMENT OF THE INTERIOR. ■ '■ ■# REPORT UlTED STATES GEOLOGICAL SURVEY THE TERRITORIES. UNITED STATES GEOIOGIST-IN-CHAKGE. YOLUIE XII. WASHINGTOIf: GOVERNMENT FEINTING OFFICE. 1879. LETTER TO THE SECRETARY. Office UNiTJic States Geological and GrEOGRAPHICAL SuEVEY OF THE TeBEITORIES, Washington, D. C, January 1, 1879. Sik: I have the honor to transmit herewith, for your approval and for publication, Volume XII of the Final Reports of the Survey under niy direction. This volume has been prepared by Prof Joseph Leidy, the eminent comparative anatomist and microscopist, who is well known as one of the most valued collaborators of the Survey, and the author of the first volume of the quarto series of Reports, entitled " Contributions to the Extinct Ver- tebrate Fauna of the Western Territories." Professor Leidy spent the greater portion of two seasons in the West under the auspices of the Survey. During this time he made a careful exploration of the country about Fort Bridger, Uinta Mountains, and the Salt Lake Basin, in search of the materials for this memoir. The use of the microscope in all branches of natural science has become so universal that the publication of the present volume in con- nection with the Survey needs no explanation. It is intended as a guide and aid to students in this new or little-known field of observation. The facility with which these small objects for study can be obtained all around us will render the work still more timely and useful to the students of this country. There are also a number of closely allied fields of inquiry, as the Diatoms, Desmids, Infusoria, Rotifera, Entomostraca, and Aquatic insects, etc., which, when pursued with the same skill and devotion, will prove equally fruitful in results." The Rhizopods are the lowest and simplest forms of animals, mostly minute, and requiring high power of the microscope to distinguish their structure. While most of them construct shells of great beauty and variety. IV LETTER TO THE SEORETAEY. their soft part consists of a jelly-like substance. This the animal has the power of extending in threads or linger-like processes, which are used as organs of locomotion and prehension, often branching. From the appear- ance of their tempoi'ary organs, resembling roots, the class of animals has received its name of Rhizopoda, meaning literally root-footed. In compensation for the smallness of these creatures, they make up in numbers, and it is questionable whether any other class of animals exceeds them in importance in the economy of nature. Geological evidence shows that they were the starting-point of animal life in time, and their agency in rock-making has not been exceeded by later higher and more visible forms. With the marine kind, known as Foraminifera, we have been longest familiar. Their beautiful many-chambered shells — for the most part just visible to the naked eye — form a large portion of the ocean-mud and the sands of the ocean-shore. Shells of Foraminifera likewise form the basis of miles of strata of limestone, such as the chalk of England and the lime- stones of which Paris and the pyramids of Egypt are built. Fresh-water Rhizopods, though not so abundant as marine forms, are ifevertheless very numerous. They mainly inhabit our lakes, ponds, and standing waters, but they also swarm in sphagnous swamps and even live in moist earth. Professor Leidy has devoted several years of study to the Fresh-water Rhizopods of the eastei-n portion of our country, and his especial object in his western expeditions was to investigate those which are to be found in the elevated regions of the Rocky Mountains. The beautiful plates which illustrate this volume were engraved by Messrs Sinclair & Son, Philadelphia, and to this firm the thanks of the Sur- vey are due for their care and skill. Very respectfully, F. V. HAYDEN, United States Geologist. To the Secretary of the Interior. ^ UNITED STATES GEOLOGICAL SUEVEY OF THE TEERITOEIES. FRESH-WATER RHIZOPODS NORTH AMERICA. BY JOSEPH l.EIDY, M. D., tROFKSSOR OF ANATOMY IN THE UNIVERSITY OP PENNSYLVANIA, AND OF NATURAL HISTORY IN SWARTHMORE COLLEGE, PENNSYLVANIA. I M « » WASHIITGTON: GOVEENMENT PEIKTING OFFICE. 1879. LETTER OF TRANSMITTAL. Philadelphia, January 1, 1879. Dear Sir : On several occasions you have expressed a desire, that, in my trips to the Western Territories, I should undertake the investigation of the microscopic forms of life which inhabit the waters. During the last four years I have studied one important class — the Rhizopods, as they occur in all fresh waters of the country, from the Atlantic border to an altitude of 10,000 feet in the Rocky Mountains. The marine forms of Rhizopods, in all times, have extensively contributed to the construction of stratified rocks The determination of the living fresh-water forms may serve as a guide to the discovery and determination of fossil forms in the vast lacus- trine formations in the interior of our continent. Herewith, I transmit my report for examination and publication, trusting it may meet with your approbation. Respectfully, JOSEPH LEIDY. Dr. F. V. Hayden, U. 8. Geologist, Washington, D. C. VII TABLE OF CONTENTS. Pago. Title of Volume XII of the Final Reports ; i Letter to the Secretary iii Title of Fresh-water Ehizopods -. v Letter of Transmittal vii Table of Contents ix Introduction 1 General Rcmarlis on the Ehizopods 4 Fresh-water Ehizopoda ■. 23 Protoplasta , 23 Protoplasta Lobosa 23 Amcoba 30 AmoBba proteus 30 verrucosa 53 radiosa ♦. 58 villosa 62 Ouramoeba C3 Ouramceba vorax 67 botulicauda .' 71 Pelomyxa '. . 72 Pelomyxa villosa '. 76 Dinamceba 60 Dinamoeba mirabilis 81 Hyalodiscus 94 Hy alodiscus rubicundus 94 Difflugia 95 Difflugia globulosa , 96 pyriformis .T'. 98 urceolata 106 cratera ." , 108 acuminata 109 lobostoma 112 arcula 116 corona 117 constricta 120 spiralis 1-4 Hyalosphenia - 1£8 Hyalosphcnia qnneata I49 papilio 1:>1 tiiiota 138 elegans l'^" Quadrula , l^'J Quadrula symmetrica - 14~ Nebela '■ 145 Nebela collaris 145 X TABLE OF CONTENTS. Pago. Nebela — Continued. Nebela flabellulum 152 carinata 154 Mppocrepis 156 ansata 1E8 barbata 1£9 caudata 160 Heleopera „ 162 Heleopera picta - 162 petricola : 165 Arcella .■ 166 Arcella vulgaris 170 disooides 173 mitrata 175 dentata '- 177 artoorea 178 Centropyxis 180 Centropyxis aculeata - 180 Cocliliopodium lt'4 CocMiopodium bilimbosum 184 vestitum 188 Protoplasta Filosa 169 Pamphagus - 190 Pamphagus mutabilis ^ 191 liyalinus 194 curvus 195 avidus 196 Pseudodifflugia 197 Pseudodifflugia gracilis 198 Cyphoderia 201 Cyphoderia ampulla 202 Campasous 204 Campascus comutus 205 Euglypha 206 Euglypha alveolata 207 ciliata 214 cristata 218 mucronata 219 bracliiata 220 Placocista 221 Placocista spinosa 221 Assulina 224 Assulina seminulum 225 Trinema 226 Trinema enchelys 226 Sphenoderia ' 229 Sphenoderia lenta 229 maorolepis 232 Heliozoa 233 ActinophryB 234 Actinophrys sol 235 picta 241 Heteroplirys 242 Heterophiys myriapoda j, 243 Eaphidiophiys 243 Eapbidiophryi^viridis 248 olegans - £50 TABLE OF CONTENTS. XI Page. Vampyrella 253 Vampyiella lateritia 253 Diploplirys : 256 Diplophrys archeri 256 ActinosphiBrmm 258 Actinospliferium eiohhomii 259 Aoantliooystis 264 AcantLocystis olisetophora 264 ? 268 ? 270 Hyalolampe 271 Hyalolampe fenestrata 271_ Clathrvilina 372' Clathruliua elegans 273 Foraminifera 277 Gromia , 277 Gromia terrioola 277 Biomy xa 281 Biomyxa vagaus 281 Lists of Fresh-water Ehizopods, indicating the many forms which occur together in certain localities -'. 289 Concluding Eemarks 294 Chief works and communications relating to the Fresh-water Ehizopods, with lists of the forms described, and a partial and probable reference of these to corresponding forms described in the body of the present work 297 Index 321 INTRODUCTION. The revelations of the microscope are perhaps not exceeded in impor- tance by those of the telescope. While exciting our curiosity, our wonder and admiration, they have proved of infinite service in advancing our knowledge of things around us. The present work, founded on suCh revelations, I have attempted to prepare in a manner to render it easy of comprehension, with the view of promoting and encouraging a taste for microscopic investigation. Dr. Carpenter, the eminent English physiologist and naturalist, in his treatise 'The Microscope and its Revelations', remarks that "it is a ten- dency common to all observers, and not by any means peculiar to micro- scopists, to describe what they believe and infer, rather than what they actually witness." There ai'e certainly peculiar difficulties in arriving at a faithful inter- pretation of microscopic observations, arising- from many causes, of which a common one is the difficulty of handling minute objects, especially active living animals, so as to examine them from every point of view. While I have endeavored to describe things as they appeared to be, I am conscious of having been unable to avoid the usual proportion of errors, for which I beg indulgence, and which I leave for others who shall pursue the same path of investigation to correct. What are Ehizopods? is a question that will be asked by perhaps most persons whose attention may be directed to the present work. They are the simplest or lowest forms of animal life, constituting the first class of the Protozoa (Greek, protos, primitive ; ^oon, animal). The Rhizopoda (Gr. rhim, root ; pous, foot : — ^root-footed animals) are mostly microscopic beings, rarely just visible to the naked eye ; though some are sufficiently large to appear as conspicuous objects. Their minute- ness is amply compensated by their multitude and world-wide distribution; 1 RHTZ 1 2 FEESH-WATER EHIZOPODS OF NOETH AMEEICA. essentially aquatic, they occur wherever there is moisture. Commencing from one's own doorstep, they may be found in almost every damp nook and crevice, savanna and marsh, pool and ditch, pond and lake, sea and ocean, and from the greatest depths of the latter to the snow-line of mount- ains. By far the greater proportion are marine, and their tiny shells enter abundantly into the composition of the ocean mud and abound in the sands of every ocean shore. They appear to have been the first representatives of animal life on earth; and if there is any truth in the theory of evolution, they represent our own remotest ancestors. Having existed for ages, their remains have largely contributed to the formation of the marine sediment- ary rocks. The particular Ehizopods which form the subjects of the present work are those usually designated as the 'Fresh-water Ehizopods', living mainly in comparatively still fresh waters, in the mud of bogs, among algae and mosses, and even on the ground in damp, shaded places. My investigations were commenced four years ago, and have been continued during that time, in intervals of leisure from teaching and ordinary business pursuits, until last summer, when I began the preparation of my report for publication. In the study of the Ehizopods, my attention has been more particularly directed to the discovery and determination of the various forms occurring in this country, rather than to the elaboration of details of structure, habits, modes of development, and other matters pertaining to their history, though these have not been entirely neglected. In the latter respects, my researches fall short of those of some of the able naturahsts of England and Germany: — Wallich, Carter, and Archer of the former, and Hertwig and Lesser, Grreeff, Cienkowski, and Schulze of the latter country. The ijlustrations accompanying the work, done in chromo-lithography, are not equal in execution to my desire, though they represent the charac- teristic appearance of the subjects in all cases, I believe, sufficiently vvrell to enable the student to recognize these when found. The original drawings made by myself, I think may be fairly viewed as approximating accuracy' at least so far as relates to the outhnes, which have invariably been drawn to a scale of measurements, so as to preserve the proportions of all parts Faults in perspective and other qualities are partially due to my own want of abihty as an artist, and partially to the difficulty of con-ectly interpret- ing the views of objects as ordinarily seen through the microscope. Many INTEODUCTIOK 3 of the illustrations exhibit varioiTS degrees of irnperfection in some of the details, due to exaggeration of defects in the original drawings, which the artists, without any knowledge of the subjects, have attempted closely to imitate. It has long been a matter of regret to me that I have not been able to secure the services of accomplished artists, educated for the special purpose to give us faithful and beautiful representations of natural-history subjects, such as we so frequently see in the scientific periodicals and other works especially of Germany and France. I think it worth while to embrace the opportunity of informing students that microscopic observations, such as those which form the basis of the present work, do not require elaborate and high-priced instruments. Such a microscope as is made by Zentmayer of Philadelphia, Beck of London, or Hartnack of Paris, and sold at prices ranging from $50 to $100, answers all ordinary purposes. The instrument should be furnished with two objective powers, of which the higher should be at least ^th or ^th of an inch focus. A still higher power being occasionally required, I have found an ^th or ^th objective of great service. I have now in use a little instrument of Beck, called the Economic Microscope, with 1-inch and ^-inch object-glasses and two eye-pieces, sold by W. H. Walmsley, No. 921 Chestnut street, Philadelphia, for $50. An important addition to the instrument, for measuring, is a micrometer, divided into fractions of a millimetre, which may be purchased for a couple of dollars. I give the above statement, not with any disposition to detract from the value of the various magnificent microscopes so much in vogue, but with the object of dispelling a common impression widely prevalent, at least among those with whom I habitually come into contact, that the kind of work such as I now put forth can be done only with the help of elaborate and expensive instruments. In aid of my researches among the Rhizopods of the Rocky Mountain Region I acknowledge the services of my friend Dr. J. Van A Carter, for- merly of Fort Bridger, now of Evanston, Wyoming Territory. It was not only under his hospitable roof that I was enabled to pursue my investiga- tions, but he conducted my expeditions into the Uinta Mountains and other places to collect materials, and withal defrayed the expenses of our trips Dr. Carter, in his appreciation of scientific matters, has been of eminent service to geologists and other naturalists visiting his region of country. 4 FEESH-WATEE EHIZOPODS OF NOETH AMEEICA. Some of my most delightful recollections are associated with expe- ditions into the Uinta Mountains conducted by Judge W. A. Carter, of Ft. Bridger, or his son-in-law Dr. J. Van A. Carter. At an elevation of from eight to ten thousand feet the mountains are covered with forests, chiefly of Fir and Pine, with a most wonderful profusion of beautiful flow- ering plants beneath. The forests here and there enclose bright, grassy meadows and ponds, favorite resorts of deer, and in these I obtained rich materials for my investigations. Whatever may be thought of the pertinence of publishing such works as the present one with the Reports of the Geological Survey of the Territories, to remove any misapprehension in the matter I deem it proper to state that my contribution has been given without pecuniary recompense. In my own judgment. Prof Hayden has acted with the most enlightened view in authorizing and encouraging such natural-history investigations as would be facilitated by explorations of the country in which his geological surveys were conducted. With the exception of the cost of publishing the present Report, the only additional expense to which I put the Survey during my explorations in the West amounted to about $222. Much expense was saved through the liberality of various railroad compa- nies in giving me the privilege of free travel and travel on half-fare. GENERAL REMARKS ON THE RHIZOPODS. The simplest kinds of Rhizopods are unprovided with a protection or support of hard parts of any kind, possessing, at least in their ordinary active condition, neither a shell nor an investing membrane. In all kinds, the soft substance of the animal mainly consists of a fluent, viscid, albumi- noid jelly, endowed with an extensile and a contractile power, by which the creature is enabled to execute all those movements which ordinarily distin- guish animal life. The motile jelly of the Rhizopod is regarded to be of the nature of the common elementary basis of organic bodies in general, and, like it, is called the protoplasm (Gr. protos, first ; plasso, I mould :— the primitive material from which organic bodies are moulded). Its resemblance in motive power to muscular tissue, or the flesh of more complex animals, led the French naturaHst Dujardin, who was the first to indicate the true nature of the Rhizopods, to give it the name of sarcode (Gr. sarx, flesh ; eidos, form). GENEEAL EEMAEKS ON THE EHIZOPODS. 5 The soft mass of protoplasm, or sarcode, forming the essential part of the body of all Ehizopods, has no internal cavity like the body-cavity of higher animals, neither has it a mouth like the higher Protozoa, nor has it stomach or intestine. Without trace of nerve elements, and without defi- nite, fixed organs of any kind, internal or external, the Rhizopod, — simplest of all animals, a mere jelly-speck, — moves about with the apparent purposes of more complex creatures. It selects and swallows i,ts appropriate food, digests it, and rejects the insoluble remains. It grows and reproduces its kind. It evolves a wonderful variety of distinctive forms, often of the utmost beauty, and, indeed, it altogether exhibits such marvelous attributes, that one is led to ask the question in what consists the superiority of ani- mals usually regarded as much higher in the scale of life. In this relationship. Dr. Carpenter remarks of the Ehizopods, "If the views which I have expressed as to the nature and relations of their living substance be correct, that substance does not present any such differentia- tion as is necessary to constitute what is commonly understood as ' organi- zation ' even of the lowest degree and simplest kind ; so that the physiolo- gist has here a case in which those vital operations which lie is accustomed to see carried on by an elaborate apparatus, are performed without any special instruments whatever, — a little particle of apparently homogeneous jelly changing itself into a greater variety of forms than the fabled Proteus, laying hold of its food without members, swallowing it without a mouth, digesting it without a stomach, appropriating its nutritious material without absorbent vessels or a circulating system, moving from place to place with- out muscles, feeling (if it has any power to do so) without nerves, propa- gating itself without genital apparatus, — and not only this, but in many instances forming shelly coverings of a symmetry and complexity not sur- passed by those of any testaceous animals." * Through the motile power of the Rhizop'od, it projects or extends portions of its protoplasm, which act as temporary organs of locomotion and prehension, and it again withdraws or contracts them so that they melt away in the mass and leave no trace of their previous existence. From their function, the extensions of protoplasm have received tlie appropriate name of pseudopods (Gr. pseudos, false ; pons, foot). These appear, in gen- eral, in different kinds of Ehizopods, in the condition of threads of extreme * Introduction to the Study of tbo Foraminifera. Preface, vii. 6 FEESH-WATEE EHIZOPODS OP NOETH AMEEIOA. delicacy, of coarser finger -like processes, or of rounded lobes. They often branch and assume a more or less root-like appearance, whence Dujardin gave the class the name of Rhizopods. As previously intimated, the simplest kinds of Rhizopods are unpro- vided with hard parts, or even a membranous investment, and they present to the outside medium in which they live nothing but the naked mass of protoplasm of which they consist. By far the greater number of the class are protected and supported by some kind of skeleton of hard material, consisting of spicules or a trellis-work of silex, or a shell of chitinoid membrane, of limestone, or of the former material. Mostly the hard part is intrinsic, or pertains to the inherent structure of the animal, but frequently is also more or less extrinsic. In the latter instances, the shell usually consists of siliceous particles, commonly hyaline quartz sand, diatom cases, and sponge spicules. Besides some general differences in the character of the soft parts, the sustaining skeleton, or protective shell, of the Rhizopods, exhibits a great variety in form, construction, and arrangement of structure ; frequently is highly intricate and often remarkable for beauty of apparent design. On the general differences observed in the soft body-mass and its pseudopods, and on the absence or presence of hard parts with their form and constitution, the ordinal and other subdivisions of the Rhizopods are founded. It however appears from the researches, especially of British authorities, such as Carpenter, Williamson, "Wallich, Brady, Parker, and Jones, that the members of the class are infinitely variable, and that indeed no absolute distinctions of species and genera exist, such as appear more definitely to characterize the higher forms of animal life. My own investi- gations rather confirm this view, and, under the circumstances, we can only regard the more conspicuous and prevailing forms as so many nominal species, in likeness with the species of higher organic forms, more or less intimately related, and by intermediate forms or varieties merging into one another. As is the case with all other groups of organic beings, few authorities agree in the classification of the Rhizopods ; and it is for convenience rather than from studied opinion that I have adopted the following ordinal arrangement CLASSIFICATION OP THE EHIZOPODS. 7 Class. EHIZOPODA. Order I. Protoplasta ; II. Heliozoa ; III. Eadiolaeia ; IV. FOEAMINIFEEA; V. MoNEEA. The distinguished French naturalist Dujardin, who first recognized the nature of the Rhizopoda, and applied to them this name, included in the class the Foraminifera and the group of Protoplasta, excepting only the genus Amoeba, although he fully understood the relationship of this with the former. The Heliozoa he viewed as another division of the Protozoa, and in his day the Radiolaria wei'e not sufficiently known to hold a recog- nized position in zoological systems. Prof Haeckel, one of the latest and highest authorities on all that concerns the lowest forms of life, includes in the class the Foraminifera, the Heliozoa, and the Radiolaria. The Protoplasta and the Monera, which names originated with him, he regards as two distinct and additional classes in his proposed kingdom of Protista (protiston, primordial). Prof Carpenter includes all the ordinal groups above indicated as Rhizopoda, but associates the Heliozoa in the order of Radiolaria. Dr. Wallich* divides the class into three orders: the Herpnemata, the Protodermata, and the Proteina. In the first are included the Gromida, Foraminifera, and Polycystina; in the second, the Thalassicollidse and Acanthometrina ; and in the third, or highest order, the Actinophryna, Lagynidse, and Amoebina. . . Prof Huxley drops the name of Rhizopoda altogether, and distributes the groups into two divisions of the Protozoa : the Monera and the Endo- plastica To the former he refers the Monera of Haeckel and the Fora- minifera ; to the latter he refers the Radiolaria, including the Heliozoa, the Protoplasta, the Grregarinidse, the Catallacta, and the Infusoria. The essen- tial character of the Monera, according to Haeckel, the founder of the order, is the absence of a" nuclei^, but this has recently been shown by Hertwig and Schulze to exist in the Foraminifera. Carter, Greeif, and others, speak of the Heliozoa as fresh-water Radiolaria. Hertwig and Lesser, who gave ■ the name of Heliozoa to the ordinal group, regard them as of a distinct class from the Radiolaria, and, excluding these, they associate the former together * Annals and Magazine of Natural History, 186:!, si, p. 438. 8 FEESH-WATBR EHIZOPODS OF NORTH AMERICA. with the Foraminifera, Protoplasta, and Monera, as Khizopoda, but" propose for this class to substitute the name of Sarcodina. In my studies of the Protozoa, or animals of the lowest subkingdom, I have habitually viewed as Rhizopods the five ordinal groups indicated in the above classification. This accords with the views of Prof F. E. Schulze, an able investigator of the class. In a recent number of the Archiv fur Mikroscopische Anatomie for 1877, p. 21, he remarks, that his researches led him to consider as pertaining to the Rhizopods, as an essentially harmonious whole, all those low forms which, during the greater part of their hfe, and especially during the period of their highest perfec- tion, hold intercourse with the exterior world, move about, and obtain food, by means of extensile processes of the viscid body-substance, which are again capable of flowing back completely into the latter. Thefirst two orders of the Rhizopods — the Protoplasta and the Heliozoa — are those which are commonly designated as the 'Fresh-water Rhizopods'; the Radiolaria and the Foraminifera, with part of the Monera, are marine. Fresh-water Rhizopods are to be found almost everywhere in positions kept continuously damp or wet, and not too much shaded. They are especially frequent and abundant in comparatively quiet waters; clear, and neither too cold, nor too much heated by the sun, such as lakes, ponds, ditches, and pools. They are also frequent in wet bogs and savannas, among mosses, in springy places, on dripping rocks, the vicinity of water- falls, springs, and fountains, and in marshes, wherever the ground is sujQBi- ciently damp or moist to promote the growth of algae They are also to be found in damp shaded places, among algse, liverworts and mosses, about the roots of sedges, rushes and grasses, or those of shrubs and trees grow- ing in or at the borders of bogs and ponds or along ditches and sluggish watercourses. They are likewise to be found with algse in damp shaded positions in the depressions and fissures of rocks, in the mouths of caves, among decaying logs, among mosses and lichens, on the bark of growing trees, and even in the crevices of walls and pavements about old dwellings and in cities. The favorite habitation of many kinds of Rhizopods is the light super- ficial ooze at the bottom of still waters, where they live in association with diatoms, desmids, and other minute algse, which form the chief food of most of these little creatures. They never penetrate into the deeper and PLACES WHEEE EHIZOPODS MAY JBE POUND. 9 usually black mud, which indeed is almost universally devoid of life of any kind. Rhizopods also occur in the flocculent materials and slimy matter adherent to most submerged objects, such as rocks, the dead boughs of trees, and the stems and leaves of aquatic plants. A frequent position is the under side of floating leaves, such as those of the Pond- lily, Nymphcea odorata; the Spatter-dock, Nuphar advena; and the Nelumbo, Nelumbium luteum. Certain kinds of Rhizopods, especially the Heliozoa, or Sun-ani- malcules, are most frequent among floating plants, such as Duck -meat, Lemna; Horn wort, Ceratophyllum ; Bladderwort, Utricularia; and the various Confervas, as Zygnema, Spirogyra, Qscillatoria, and the Water-purse, Sydrodietyon. In no other position have I found Rhizopods of the kind under con- sideration in such profusion, number, and beauty of form as in sphagnous bogs, living in the moist or wet Bog-moss, or Sphagnum. Sometimes I have found this particular moss actually to swarm with multitudes of these creatures of the most extraordinar}'- kinds and. in the most highly developed condition. A drop of water squeezed from a little pinch of Bog-moss has often yielded scores of half a dozen genera and a greater number of species. Frequently, however, the Sphagnum of many localities contains compara- tively few Rhizopods, though I have rarely found them entirely absent from this moss. Other mosses and liverworts I have not observed to be specially favorite habitations of the Rhizopods, not even such aquatic kinds as the Fontinalis. Notwithstanding the experience of four years' exploration and obser- vation, I have not been able to determine the exact conditions under which particular Rhizopods are to be obtained with certainty and in any consid- erable numbers. In general, they are to be found in greatest number and variety under the peculiar conditions favorable to them, in old established ponds, bogs, etc., which are not liable to become completely dried up in the summer season. At times, however, I have found a profusion of one or two forms in some localities, in which, in another season, I could find but few or none. Sometimes I have found many individuals of a particular kind in a shallow pond of recent origin, which, after drying up in the sunamer and being renewed the following spring, yielded no more of the same. Sometimes the most unpromising places have produced an unex- 10 FEBSH-WATEE EHIZOPODS OF NOETH AMERICA. pected and occasionally a surprisingly rich supply of Rhizopods, and repeatedly the most promising places have yielded exceedingly few. The Rhizopods may be found at all temperate seasons of the year; and even in winter, when out of the influence of a freezing cold, a few may be discovered, though mostly in a comparatively inactive state. Frost or a freezing temperature appears to destroy them. They do not live among actively decaying vegetal matter, nor are they to be found in foul water. I have further not been able to discover them in brackish waters on the sea-coast, though I detected a few forms in feebly saline or alkaline waters in the Bridger Valley of "Wyoming Territory. The Fresh-water Rhizopods appear to inhabit indiscriminately almost any kind of country, no matter what may be its rocky constitution, except it be limestone. According to my experience, they are comparatively rare in limestone districts, and I have repeatedly been disappointed in my expectation of finding them in some large limestone springs in which grew a profusion of Anacharis, Chara, and other aquatic plants. This has appeared the more surprising when it is considered that the allied marine order, the Foraminifera, have so largely contributed to the formation of the limestone rocks. The mode I have habitually adopted for collecting Rhizopods, which is also equally well adapted for collecting man}, other microscopic organ- isms, plants, and animals, is as follows : For ponds, ditches, or other waters, I use a small tin ladle^ or dipper, such as is commonly employed for domestic purposes. Into the handle I insert a stick of convenient length, and for this I usually carry with me a jointed pole of two or three pieces, each about five feet. The dipper is used by slowly skimming the edge along the bottom of the water so as to take up only the most superficial portion of the ooze, which is then gently raised from the water and transferred to a glass jar. A small hole in the bottom of the ladle favors the retention of the ■ collected material, but care should be taken that it is not so large as to permit the material to stream through. After the collecting-jar is full, if more of the material is wanted, after allowing that in the bottle to settle, I pour off a portion of the water and supply an additional quantity from the locality. Usually, I have proved more successful in obtaining Rhizopods from the ooze near the shores of lakes and ponds than I have in deeper water- COLLECTlOlJr AND EXAMIlfATION OP EHIZOPODS. 11 but this I suspect was mainly due to the circumstance that near the shore I could see the ooze at the bottom of the water, and could much better manage to collect the desired material. Aquatic plants, if rooted in the mud, should be carefully cut off and gently lifted from the water so as to disturb as little as possible the adherent materials. A sufficient quantity being placed in a tin preserving- can or other vessel, water from other portions of the plants may be squeezed upon that which is retained. Wet Sphagnum may be collected and put in tin preserving-cans, and the water of other portions may be squeezed upon the portion preserved. The same process may be pursued with other mosses. From the surface of the ground in wet places, to collect the Rhizopods, it is sufficient to scrape up, with the broad blade of a knife, the green algous material with which the animals are usually associated. The materials collected from waters I have preserved, for convenient examination from time to time, by putting them in dishes about three inches in depth, filling them with fresh water, and placing them in the window where they obtain an abundance of light, but without receiving the direct rays of the sun. If exposed to the sun, the water becomes unduly heaterl, and all living things speedily die and decompose. Care should also be observed not to have too much material in the same dish ; and I have found it best to preserve a stratum of ooze which, when settled, is not more than from a line to the eighth of an inch in depth. Some Duck-meat, Lemha, Bladderwort, Utriculdria, Spirogyra, or other plant, collected, and placed in the water, greatly promotes its freshness and continued purity. The dishes should be covered with panes of glass to exclude the dust and prevent evaporation. A day or two after the materials have been placed in dishes, the sediment has deposited and the water become clear. In this condition, there may usually be observed on the surface of the sediment a continuous thin film, or patches of a yellowish, yellowish-green, or green color. The film, or patches of the same material^ is more tenacious than the deposit beneath, and consists of the various living organisms, especially diatoms, desmids, rhizopods, etc., which have extricated themselves from the ooze to occupy the most favorable position to continue their functions. Indeed, it is a remarkable phenomenon to observe with what ease and rapidity these extremely minute living creatures can free themselves from the depths of 12 FRESH-WATER RHIZOPODS OF NORTH AMERICA. the mud in which they had been buried, to occupy a position on its surface, where they receive the full benefit of the conditions necessary to their life. From the living film, as it might not inappropriately be called, the desired objects for examination are to be obtained. Portions may be lifted with a glass tube closed at the upper end by the finger, and then with the other end brought into contact gently with the surface of the ooze. By raising the finger, the pressure of the water forces a portion of the ooze into the tube, when, the finger being replaced, a drop of the contents of the tube may be transferred to a glass slide or an animalcula cage for the field of the microscope. The materials collected and disposed of in the manner above described may be preserved in a good condition for examination for weeks together, and indeed without any further care in this way I have kept a stock of Rhizopods alive during the winter. The Rhizopods collected with wet Sphagnum, or other mosses, or on damp earth, may be readily kept in good condition for examination in glass cases, for which purpose common wide-mouthed candy -jars answer. They should be kept in the light in the same manner as the dishes of water. With Sphagnum I have retained its peculiar Rhizopods alive the whole year through. To examine the Rhizopods of Sphagnum or other mosses, or from the algous film of damp places, wet a fragment, teaze it with a knife and forceps, and press the water from the pulpy mass into a watch-crystal. A drop of the sediment collected is then to be transferred to the field of the microscope. The diflferent forms of fresh- water Rhizopods are not generally restricted to diflferent localities or positions, but are commonly found more or less in association together. Usually the naked forms, and especially the larger ones, the DiflBugias and the Arcellas, are found most frequently, abundantly and best developed, in the ooze of bodies of water. The Euglyphas, Nebelas, and their nearer allies, are in like manner most frequent in the moist Sphagnum of bogs; and the Heliozoa in the positions previously indicated. The chief localities from which I have myself collected the materials of the present work are as follows : OEDEES OF EHIZOPODS— EADIOLAEIA, 13 Ponds, springs, and marshes in the vicinity of Philadelphia, but espe- cially the ditches which traverse the great meadows below the city, in the alluvial triangle called the Neck, between the Delaware River and the mouth of the Schuylkill River. Ponds, marshes, etc , along the course of the Delaware River, both in Pennsylvania and New Jersey, from Philadelphia to the Delaware Water Gap. Sphagnous bogs, pools, and ponds on the Pokono Mountain, Monroe County, and on Broad Mountain, Schuylkill County, Pennsylvania The lower part of the State of New Jersey, along the course of the Camden and Atlantic City Railway, and along the course of the Camden and Cape May Railway. Throughout this broad region materials were col- lected from many localities: ponds and pools, sphagnous bogs, cedar swamps, savannas, and cranberry lands. Also Lake Hattacawana, or Budd's Lake, on Schooley's Mountain, Morris County, New Jersey. The vicinity of Noank, on the coast of Connecticut, and of Newport, Rhode Island. Bridger Valley, in the southwestern corner of Wyoming Temtory, and the Uinta Mountains to the height of 10,000 feet, in the same region. Partridge Island, at the head of the Bay of Fundy, Nova Scotia. Before entering- in detail upon the spedial subjects of my studies, the Fresh-water Rhizopods, nearly all of which pertain to the orders of the Protoplasta and the Heliozoa, some remarks on the characters of the other orders of the class may not be out of place. The Radiolaria (radiolus, a little ray) are the subjects of an ela- borate and magnificent work by Dr. Ernst Haeckel, Professor of Natural History, in Jena.* They are exclusively marine Rhizopods, comprising many wonderfully beautiful forms, living and swimming in vast multitudes in the superficial waters of the ocean. They are generally minute, and are the most complex in their constitution of any of the Rhizopods. They are commonlj'" furnished with a siliceous or flinty skeleton, which, in variety of form, symmetry, and intricacy of construction, is a marvel^of beauty. The material of the skeleton is derived from the exceedingly small proportion • * Die Eadiolarien (Ehizopoda Radiolaria), Berlin, 1862. 14 FEESH-WATEE EHIZOPODS OF NOETH AMEEIOA of silex contained in the sea-water. After death, the skeletons of the Eadio- laria sink to the bottom of the ocean, where they accumulate as an abun- dant component of the mud. In the island of Barbadoes, extensive rock strata of the Tertiary period, 1100 feet. in thickness, consisting of marls, tripoli, and ferruginous sand- stones, are largely composed of the siliceous skeletons of Radiolaria. Material from these strata called 'Barbadoes earth' is well known to microscopists, and is highly prized for the perfection and beauty of the forms it supplies. Likewise, in the Nicobar Islands, of the Indian Archi- pelago, the solid nucleus of the islands, consisting of clays, marls and arenaceous marls of Tertiary age, 2000 feet in thickness, is largely com- posed of the remains of Radiolaria. According to Haeckel, the soft body of the Radiolaria is more highly organized than thaj of the Foraminifera and Heliozoa. It contains a cen- tral capsule of firm membrane enclosing masses of minute cells. The exterior protoplasm commonly contains numerous yellow cells enclosing starch-grains, and in some forms also large vacuoles, and from it emanate in all directions countlesg pseudopodal rays. Most Radiolaria possess a highly complex skeleton composed of silex, exhibiting in different kinds a wonderful variety of the strangest and most elegant forms. Sometimes it consists of a simple trellised ball, some- times a series of several such 'balls enclosed concentrically in one another, and connected together by radial bars. Grenerally delicate spines, often branching, radiate from the surface of the balls. In other instances, the skeleton consists of a star mostly composed of twenty spines, arranged in definite order and united in a common centre. In some Radiolaria, the skeleton is a delicate, many-chambered shell, as in the Foraminifera. Indeed, says Prof. Haeckel, no other group of organisms develop in the construction of their skeleton such a variety of fundamental forms with such geometrical regularity, and such elegant architecture. The Foraminifera {foramen, an aperture; fero, to bear) constitute by far the most important order of the Rhizopods, especially from the vast quantities in whfch they have existed in all times from the earhest Imown appearance of life on earth until now, and from the enormous extent in. which their remains have contributed to the formation of rocks. They are marine shell-bearing animals, mostly living at the bottom of oceans and OEDEKS OF EHIZOPODS— FOEAMLNIFEEA. 15 seas, some attached, but generally free, and creeping on tlie surface of sea- weeds, on the mud, the sands and rocks, or on dead shells ai:d corals, or the lifeless fixed hard parts of other living animals, as the shells of moUusks, corals, sertularians, and sponges. Large numbers are pelagic, or live on the high seas, swimming in the superficial water, while their dead shells form an incessant rain, and contribute largely to the formation of the ocean mud. Of their class, the Foraminifera have been longest and best known, and their tiny and beautiful shells have been the subjects of many descrip- tions and illustrations. The characters of Ihe order have been especially elaborated in more recent works, among which , may be mentioned the "Organization of the Polythalamia" by Dr. Max S. Schultze, and the "Introduction to the Study of the Foraminifera" by Dr. William B. Car- penter. The Foraminifera, though generally too minute to be distinguished by the naked eye, are readily detected with a good pocket-lens. They are commonly largest in tropical seas, and even the same species are better developed in warmer than in colder latitudes. A few, the giants of their kind, are conspicuous for their size, and range even to the diameter of seve- ral inches. In former ages they frequently reached a greater growth, so that fossil forms are commonly larger than those now living. Some of the extinct species exceed in size double that of any known existing ones. The Foraminifera are provided with a shell, mostly calcareous, hnt often partially calcareous with incorporated siliceous sand, or it is composed of sand-grains alone cemented together. With few exceptions, the shells are partitioned into many chambers, and the most common forms, which are spiral, so nearly resemble the shells of the Nautilus and Ammonite, that until a comparatively late period all were classed together as Polythalamia (Gr. polus, many ; tJialamos, chamber) or Cephalopoda (the Cuttle-fishes). D'Orbigny, recognizing in the shells of the Nautilus and Ammonite that the chambers were traversed by a tube, while in the shells of the so-called microscopic Cephalopods the chambers communicated by one or more holes, called the former Siphonifera (siphon, a tube; fero, I carry) and the latter Foraminifera. In a systematic arrangement of the Cephalopods in 1825, D'Orbigny still retained the Foraminifera as an order. Dr. Carpenter remarks that "no suspicion appears at that time to have crossed the mind 16 FEESH-WATEll EHIZOPODS OF NOETH AMEEICA. of M. D'Orbigny that the place of these organisms might be among the lowest instead of among the highest of the Invertebrata." The true nature of the Foraminifera, and their relationship with Amoeba, Difflugia, and other animals of the kind, was first recognized by the accurate observer M. Dujardin. In the Annales des Sciences Naturelles for 1835, there are two articles from M. Dujardin, entitled "New Observations on the Micro- scopic Cephalopods" and "New Observations on the pretended Micro- scopic Cephalopods". The author remarks that he has observed several genera of these animals from the Mediterranean in a living condition, nota- bly MiUola, Rotalia, etc. The segments of the shell successively augment in volume, and are occupied with a red or orange-colored animal matter, of the consistence of thick mucus, very contractile, and susceptible of length- ening into threads. In conclusion, the author remarks that "if one wishes to assign to these animals their place in the animal kingdom, in considering the absence of organs, the homogeneity and simplicity of their material — a sort of mucus endowed with spontaneous movement and contractility — one is led to place them in the lowest rank I first designated them under the name of Symplectomferes, only having in view the succession of similar parts rolled together, in the known species ; but the observation of Gromia • has led me to prefer the name Rhizopods, to express their singular mode of creeping by means of threads, which extend and branch like roots." Dr. Carpenter divides the Foraminifera into two suborders: the Imper- forata and the Perforata, founded on the circumstances that in the former the shell has mostly but a single orifice of communication with the exterior for the emission of the pseudopods, while in the latter the shell has its outer walls everywhere minutely perforated for the same purpose The sarcode of the Foraminifera consists of a viscid protoplasm, usu- ally more or less colored yellowish, brown, or red ; the color being deepest in the earlier formed chambers of the shell, and becoming less towards the last one, in which it is very feeble or absent altogether. The protoplasm contains granular matter, and vacuoles, or drops of more liquid matter than that of the general mass of the sarcode. Nuclei have commonly been sup- posed to be absent, but recent researches of Her twig* and Schulzef have proved their existence. The pseudopods of the Foraminifera extend as * Jenaische Zeitsohrift, x, 1876,41. tArchiv f. Mikros. Anat. 18/7 9. ORDERS OF RHIZOPODS— FORAMINIFERA. 17 exceedingly delicate threads, often in large number, from the one or several mouths or numerous pores of the shell. They divide and subdivide into finer and finer threads, which inosculate freely where they come into con- tact with one another, so as to produce an intricate net. From this condi- tion, Dr. Carpenter has applied to the order the name of Eeticularia. The pseudopods exhibit continual changes in their arrangement, and an incessant circulation in their course. In the larger threads, two streams are observed at the same time, passing in opposite directions ; in the finest threads, a single stream moves outward or inward. The currents carry along granules of the protoplasm, and also convey particles of food which may be caught in the way of the pseudopods. Sea-sands contain as an important constituent the dead shells of recent Foi'aminifera, though in very variable proportions. They are generally most abundant in the sands of warmer latitudes, and especially on shores prbfusely furnished with sea-weeds. Plancus,* who, according to D'Orbigny,t was the first to describe and figure the shells of Foraminifei'a, counted 6000 individuals in an ounce of , sand from the Adriatic. D'Orbigny estimated that there were 160,000 in a gramme of selected sand from the Antilles. Schultzef gives 1,500,000 as the number he found in fifteen grammes of sand from Gaeta on the coast of Sicily. Even on the comparatively ban-en shores of New Jersey, consisting of quartz sand, foraminiferous shells occur in notable quantity. In a portidn scraped from the surface between tides, at Atlantic City, I estimated that there were 18,700 shells to the ounce avoirdupois, all of a single species of Nonionina In another sample, from Cape May, I obtained 38,400 shells to the ounce, likewise of the one species. In sand collected by scraping up the long white lines on the bathing beach at Newport, Ehode Island, occupying an indenture of the rocky coast, covered with sea-weeds, foraminiferous shells were found to be much more numerous, but, excepting in the case of some examples of Miliola, of smaller size. In an ounce of the sand, I estimated that there were about 280,000 shells, of several genera and species. It would appear as if the deep-sea mud almost universally was mainly 'Ariminensis de conchis minus notls. Venice 17.39. tForaminif^res: La Sagra, L'isle do Cuba. Paris, IHOO. Introduction, vii. t Organismus d. Poly thai amieu, 1854, p. L'5. ii KHIZ 18 FRESHWATER RHIZOPODS OF NORTH AMERICA. derived from the shells of Foraminifera. The sediment of the Atlantic Ocean is so largely constituted of one kind of foraminiferous shell, the Globigeriha Mloides, that the mud is now frequently spoken of as the 'Glo- bigerina ooze'; and this material is likewise found in the Pacific and other oceans and seas. In speaking of the composition of the ocean mud, Mr. Thomson re- marks : "The dredging at 2435 fathoms at the mouth of the Bay of Biscay gave a very fair idea of the condition of the bottom of the sea over an enormous area, as we know from many observations which have now been made, with the various sounding instruments contrived to bring up a sample of' the bottom. On that occasion the dredge brought up about one and a half cwt. of calcareous mud. The matter contained in the dredge consisted mainly of a compact 'mortar', of a bluish color, passing into a thin — evidently superficial — layer, much softer and more creamy in consist- ence and of a yellowish color. Under the microscope the surface layer was found to consist chiefly of entire shells of GloUgerina buUoides, large and small, and fragments of such shells mixed with a quantity of amorphous calcareous matter in fine particles, little fine sand, etc. Below the surface layer the sediment becomes gradually more compact, and a slight grey color, due probably to the decomposing organic matter, becomes more pro- nounced, while perfect shells of Grlobigerina almost entirely disappear, frag- ments become smaller, and calcareous mud, structureless and in a fine state of division, is in greatly preponderating proportion. "One can have no doubt, on examining this sediment, that it is formed in the main by the accumulation and disintegration of the shells of Globi- gerina — the shells fresh, whole and living in the surface layer of the deposit, and in the lower layers dead and gradually crumbling down by the decom- position of their organic cement, and by the pressure of the layers above — an animal formation in fact being formed very much in the same way as in the accumulation of vegetal matter in a peat bog, by life and growth above, and death, retarded decomposition and compression beneath."* When we are thus informed of the constitution of ocean mud, we are fully prepared to learn that vast rock-formations of past ages are composed of the shells of Foraminifera. D'Orbigny observes that the ' calcaire gros- sier' of the Paris basin, a coarse limestone of Tertiary age, is chiefly com- »The Deiiths of tho Sea, p. 410. OEDEES OF EHIZOPODS— MONEEA. 19 posed of the shells of these animals. As this rock is employed for building, he remarks that it is no exaggeration to say that Paris, as well as the towns and villages of some of the surrounding departments, are almost built up of Foraminifera. The limestones of early Tertiary age of Southern Europe and Asia and of Northern Africa are largely constituted of Nummulites (nwmmnlus, a small coin), — ^foraminiferous shells resembling money in shape, and ranging from the size of a pin-head to that of a dollar. This 'Nummulitic Lime- stone ' attains a thickness of several thousand feet, and contributes to form those great mountain chains, the Pyrenees, Alps, Apennines, Carpathians, and the Himalayas, often including their snow-clad peaks. It extends through the Mediterranean basin, Asia Minor, and Persia, into India. In Egypt, it furnished building-stone for the great Pyramids. The chalk of Europe, a soft limestone of an earlier time than the former, is also chiefly composed of the shells and their decomposed remains of Foraminifera. The so-called green-sands, like those of our neighboring States, New Jersey and Delaware, of the same and other periods, from the earliest to the lateist times, have been largely due to Foraminifera. Prof. Bailey has further shown that a similar material to the green-sand is now in process of formation in the Gulf of Mexico, through the same agency. The fossil-bearing rocks of earliest time present illustrations of the same character. Limestones of the Carboniferous age have been largely due to foraminiferous shells, and one kind has been specially named 'Fusulina Limestone', from the abundance of shells it contains of the foraminiferous genus Fusulina. The group of organic beings designated as Monera (Gr. moneres, simple) was first definitely characterized by Prof. Haeckel, who describes it in his Monograph as follows : Organisms without organs, which in the perfectly developed condition consist of a freely movable, naked body, composed of a completely struc- tureless and homogeneous sarcode (protoplasm). Never diiferentiating nuclei within the homogeneous protoplasm. Motion occurs through con- tractions of the homogeneous body- substance, and through extension of variable processes (pseudopods), which either remain simple, or branch and anastomose. Nourishment occurs in various ways, mostly after th^ manner of Rhizopods Reproduction takes place only in an asexual manner, 20 FEESH-WATEE EHIZOPODS OP I^TOETH AMEEIOA. through division. Often, though not always, the free moving condition interchanges with one of rest, during which the body excretes and encloses itself in a structureless investment* Thouo-h Prof. Haeckel has indicated and described a number of fresh- water spedes of Monera, I am not sure that I have had the opportunity of finding any of them, excepting perhaps the genus Vampyrella of Cieii- kowski, which he ascribes to the same order. In his History of Creation, Prof. Haeckel observes: "In a state of rest most Monera appear as small globules of slime, invisible or barely visi- ble to the naked eye, and at most about the size of a pin-head. When the Moner moves, there are produced on the surface of the little slime ball, finger- like processes or very fine radiating threads, the so-called false feet or pseudopods. The latter are simple continuous processes of the structure- less albumen-like mass of which the body consists. We are unable to perceive different parts in it, and we can obtain direct proof of the absolute simplicity of the semi-fluid mass of albumen, for with the aid of the micro- scope we can follow the Moner as it receives its nourishment. When minute bodies suitable for food, as, for instance, small particles of decayed organic bodies or microscopic plants and infusoria, accidentally come into contact with the Moner, they remain hanging to the sticky surface of the semi-fluid mass of slime, and here produce an irritation, which is followed by a strong afflux from the slimy mass of the body, and they become finally completely enclosed by it, or they are drawn into the body of the Moner by displacement of the several albuminous particles and there digested, being absorbed by simple diffusion (endosmosis). "Just as simple as is the nourishment, is the mode of reproduction of these primitive beings, which one cannot positively call animal or plant. All Monera propagate themselves only in an asexual manner by self- division. When such a speck, for example, a Protamceba or a Protogenes, has attained a certain size by the assimilation of foreign albuminous matter, it falls into two pieces ; there is formed a constriction around the middle, which finally leads to the separation of the two halves. Each half becomes rounded, and then appears as an independent individual, which commences anew the simple play of the vital phenomena of nutrition and propagation. In other Monera {Vampyrella) the body in the process of propagation, • ^ __^ * Biologisclic Studieii, 1870, 68. OEDEES OF RHIZOPODS— CHALLENGEEroA. 21 instead of two, falls into four equal parts, and in others again (Protomonas, Frotomyxa, Myxastrum) at once into a large number of small globules of slime, each of which again by simple growth becomes like the parent body." * Sir Wyville Thomson, in the Voyage of the Challenger, briefly describes certain Rhizopods, which he refers to a new order. On page 341 of the work indicated, he says: "In the investigations with the towing-net, made by Mr. Murray during the latter part of the cruise, at all depths, about thirty species or more were procured of a beautiful group of minute forms approaching, but in many important points diflfering. from the Radiolarians. This order have apparently hitherto escaped observation, and I retain for the type genus the name Challengeria, and for the Order that of 'Challengerida'. As a rule these forms are extremely minute, although some of them approach in size the smaller Radiolarians. They consist usually of a single chamber of silica varying greatly in form, sometimes triangular, soUietimes lenticular, and frequently globular or flask-shaped ; with a single opening usually guarded by a beautifully formed and fre- quently highly-ornamented lip. The contents of the shell consist of a mass of granular sarcode, with one or more large well defined granular nuclei, and a number of dark brown, sometimes nearly black, rounded compound granular masses. The Challengerida are essentially Rhizopods with mono- thalamous siliceous shells ; and their zoological position may be not very far from such forms as Gromia." Nothing is said of the characters of the pseudopods ; but should they be of the same kind as those of Gromia, this, with the new forms, might conveniently be associated in the same order. * Naturliclie Schopfangsgeschichte, 1872, 166. FRESH-WATER RHIZOPODS. PROTOPLASTA. Froios, first ; plasso, I form or mould. The Protoplasta comprise by far the greater number of the Fresh- water Rhizopods,. and include nearly all the known forms except the Heli- ozoa, or Sun-animalcules. They are divisible into two sub-orders, the liobosa and the FiJosa, founded mainly on the difference of the pseudo- pods, which in the former are comparatively thick, finger-like or lobose, and in the latter filamentous and of extreme delicacy. Some of the Protoplasts are naked, usually have no real distinction in the relative position of parts, and emit pseudopods from any portion of the' body-mass, though even most of these when in movement, for the time' being, may have the body more or less differentiated into an anterior and a posterior region. The greater number of the Protoplasts are provided with an exterior shell, commonly of a more or less flask- or vase-like shape, and, with few exceptions, having a single orifice, from which the pseudopods are projected. The shell is an excreted membrane, chitinoid or siliceous in character, or it is constructed of siliceous sand or particles of similar con- stitution, but, so far as known, appears never to be composed of carbonate of lime. PROTOPLASTA LOBOSA. The liObose Protoplasts, represented by the familiar Amoeba, Difflugia, Arcella, as well as by many other less known genera, are princi- pally characterized, as indicated in the name, from the comparatively thick, lobe-like, or blunt finger-like form of the pseudopods. 23 24 FRESHWATER RHIZOPODS OF NORTH AMERICA. In the Lobose Protoplasts, more than in any other Rhizopods, the sar- code mass of the body exhibits a tendency to differentiate an exterior, usually more consistent layer of protoplasm, which, though actually con- tinuous with the interior, ordinarily more fluent protoplasm, seems like an investing membrane, preventing the escape of the latter. For convenience, the two portions of protoplasm, differently related in position, have l)een appropriately termed the Endosarc and the Ectosarc (Gr melon, within ; ektos, outside; sarx, flesh). The ectosarc appears as the exterior clear protojjlasm ; the endosarc as the interior granular protoplasm, though high powers of the microscope generally reveal an infinitely fine granular constitution also 1o the former. Dr. Wallich regards the endosarc and ectosarc as temporarily distinct portions of the sarcode, mutually convertible into one another. The ecto- sarc becomes differentiated from the endosarc by contact with the outside medium in which the animal lives, and from time to time reverts again to the condition of the more fluent endosarc within. From this view, as intimated by Dr. Wallich himself, the ectosarc is due to a temporary and partial coagulation of the endosarc coming into contact with the water in which the animal lives, and again reverts to the condition of the more fluent endosarc as it retreats to the mass of the latter within the body. The process reminds one of the cooling of a molten mass of metal at the sides of a crucible, and the melting-away again of the crust as it is stirred from the sides into the remainder of the molten mass within. In the movements of the sarcode mass of the body, as exemplified in an Amoeba, a temporary increase of the ectosarc may occur in one or more positions, accompanied with a proportionate flow or drain of hyaline protoplasm from the contiguous endosarc. A reduction in thickness of the ectosarc follows an absorption of the clear protoplasm among the more visible granular constitvients of the endosarc. The pseudopods of the Lobosa commence as projections of the clear ectosarc, and may continue as silch in their extension unless unusually pro- longed or thick. In the latter cases they are accompanied to a variable extent with an influx of the. endosarc. They are mostly digitiform or finger-like processes, or, in other words, are cylindrical, with rounded ends, variable in number and length, often simple, frequently more or less ramose, but almost never anastomosing. Sometimes they are pointed, and PKOTOPLASTA— THE LOBOSE PKOTOPLASTS. 25 indeed in the same species under different circumstances they may be either bhmt or pointed. The endosarc is essentially granular ; that is to say, it consists of a motile hyaline protoplasm, not differentiated from the ectosarc, except in its less consistence and in the thorough diffusion of conspicuous granular elements. These occur in all gradations of size, from those which are imiAeasurably fine and indistinct up to the largest granules which are more or less darkly defined, and resemble oil-molecules. Besides the more generally diffused granular constituents,, the endosarc contains variable pro- portions of larger spherical corpuscles, clear or finely granular, and mostly colorless or pale yellowish, but in some species usually of a bright green color, and apparently of the nature of chlorophyl. An important element of the endosarc is the nucleus, a comparatively large spherical or compressed spherical corpuscle, colorless, and mostly clear, but sometimes finely granular, or more distinctly coarsely and uniformly granular. In the naked forms of the Lobosa, while in motion, the nucleus usually occupies a position at the posterior part of the body, or at least is placed back of the centre In most of the shell-covered forms it occupies a corresponding position ; that is to say, in the part most remote from the mouth of the shell, — in the fundus or upper part of the body. In some forms, as in Arcella, there are two or more nuclei occupying a position on each side of the fundus. Another element of the endosarc, usually situated at its confines and encroaching on the ectosarc, is the contractile or pulsating vesicle. This appears as a clear, colorless, or pale roseate sphere, which is observed' very slowly to enlarge, then rather abruptly to collapse and for the moment dis- appear, again to reappear, commonly in the same position. The successive movements of the vesicle occur with a certain degree of regularity, or rhythm, whence the name of pulsating vesicle. It appears to be due to a gradual concentration of water from all parts of the sarcode mass of the body, forming a drop, which when it reaches a certain size excites con- traction and is expelled. The phenomenon is remarkable, and is in a measure subservient to a respiratory as well as to an excretory function. In the naked Lobosa, the contractile vesicle usually occupies a position posterior to the nucleus or at the back of the body near the surface: In the shell-covered kinds of flask- or vase-Hke shape, there are commonly 26 EEBSH- WATER EHIZOPODS OF NORTH AMERICA. several contractile vesicles situated at the periphery of the body adjacent to the nucleus. In Arcella, the greatest number of contractile vesicles occur, and are ordinarily seen, as the animals are viewed from above or below, along the border of the sarcode mass. Food swallowed by the Lobosa and other Rhizopods, and indeed by most of the Protozoa, appears in the endosarc, commonly in spherical balls, mingled with the other constituents. These balls, or rather the spaces occupied by them, have been called vacuoles, and are usually regarded as of temporary character. Ehrenberg supposed them to be actual stomachs, and hence the name of Polygastrica (Gr. polus, many ; gaster, stomach), which he apphed to all the Protozoa, including other forms now generally regarded as pertaining to the vegetal kingdom. Dr. Wallich considers the so-called vacuoles, or food- vesicles, not in the light of mere spaces, but as temporary vesicles of ectosarc, due to inver- sion of portions of the exterior ectosarc at the time of the inception of the food, or to the contact of water with portions of the endosarc. The food- balls commonly appear with some degree of uniformity in size, and they vary in color and constitution according to the nature of the food and the changes it undergoes during digestion in the endosarc. The solid food in the balls often appears surrounded with a more translucent area than the contiguous endosarc, due to water swallowed with the food Frequently, however, the solid food appears without the translucent area, and in du'ect contact with the endosarc, in which cases liquid originally ingested with the food and altered in some way has probably been drained off into the con- tiguous endosarc. Among the food constituents of the endosarc there frequently occur solid bodies of different forms and extremely different sizes, with or without surrounding Hquid, such as diatoms, desmids, fragments of vegetal tissues, and even other Ehizopods included in their shells. Associated in like manner with the ordinary food-balls, there are fre- quently to be noticed drops of liquid, clear and colorless, or colored, mingled with the other materials of the endosarc. , These particular liquid drops, water-vacuoles or vesicles containing liquid, are due to water swal- lowed in drops, or imbibed and accumulated in drops, or they are the result of more consistent food liquefied in the process of digestion. The food appears to be swallowed by the Lobosa, not by a mere PEOTOPLASTA— THE LOBOSE PEOTOPLASTS. 27 adherence of the material to a viscid substance, and a gradual entangle- ment and sinking of the food into the body, but through an active exten- sion or flowing of the ectosarc over it, with or without the aid of the pseudo- pods. In the naked forms, the inception may occur in any position of the exterior surface of the body, but, according to the researches of Prof. Duncan,* would appear ordinarily to take place at the posterior extremity, where the endosarc is nearest to or actually reaches the surface. Some of my latest observations apparently confirm this view. Whatever may be the position of ingestion in the naked Lobosa, excreta are ordinarily discharged at the posterior extremity of the body adjacent to the position of the contractile vesicle Although there is no true vent, like the positions of the contractile vesicle and nucleus, the position of dis- charge of excrement maintains a certain degree of constancy. In the shell-covered Lobosa, the food and water are ingested at the mouth of the shell, usually through the agency of the pseudopods, and the egesta are discharged in the same position at the base of the pseudopods, if these happen to be protruded. Many of the Lobosa exhibit, among the constituents of the endosarc, variable proportions of clear, colorless or yellowish oil-globules, and also starch-granules. The latter are no doubt often swallowed as part of the food; but in many cases they appear as if they were an intrinsic element of the endosarc. Most of the naked Lobosa frequently contain in the endqsarc more or .less angular particles of quartz sand ; sometimes a few grains, sometimes in large and truly astonishing quantities. The shell-covered Lobosa usually do not contain this material, at least in any obvious quantity. Another frequent constituent of the endosarc, especially in some of the Amoebse, consists of minute crystals, often quite distinct, though it is not easy to make out their exact form and constitution. They sometimes appear as octahedrons, rhombohedrons, and hexagonal tables. Auerbachf supposes them to be of a fatty nature ; Carter J describes them as octahe- drons, or modifications of the same, and as probably consisting of oxalate of lime ; and Wallich § speaks of them as rhombohedrons, probably of car- * Popular Science Review, 1877, 217. + Zeitsohrift f. wis. Zoologie, 1856, 309. t Annals and Magazine of Natural History, 1863, xii, 33. J Ibidem, 1863, xi, 434 ; xii, 135. 28 FRESH- WATEK RHIZOPODS OF NORTH AMERICA. bonate of lime, and again he refers them to the hexagonal system. The. crystals sometimes occur in notable quantity, even in young specimens of Amoeba, and are quite conspicuous ; at other times, even in what appear to be the same species, they are few and small, or not clearly evident. The crystals, unlike the quartz sand, appear to be an intrinsic element of the animal. There is yet little positively known in relation to the modes of repro- duction of Rhizopods, though it is certain that a common mode is by division, as has been observed in some of the naked Lobosa, Heliozoa, and Monera. The opportunities for observing the process have appeared to me to be by no means frequent ; for in all the four years of my study of the Fresh-water^ Rhizopods, I met with an Amoeba in the state of division in but few instances, and the common Sun-animalcule, Actinophrys sol, but rarely. The shell-covered Protoplasts are frequently found in pairs, with the shells movith to mouth. When the shells are sufficiently translucent to allow the soft parts within to be seen, at times it is observed that these become confluent in one mass, which flows to and fro from one shell to the othei'. The mass finally dividing again into two, the individuals with their shells become separated without apparent change from the original state. This condition of union of a pair is commonly named 'conjugation', and has been supposed to hold a relation with the act of reproduction, though it has not been positively proved to be so. From certain appearances, hereafter to be considered in the special cases, I have suspected that many of the supposed examples of conjuga- tion are really due to reproduction through division. From the appear- ances alluded to, there is reason to suspect that from time to time the shell- covered Protoplasts, under appropiiate conditions, — such as are induced by being well fed, so that the animal is in a highly active condition, and the shell is surcharged with sarcode, — quickly project one half the mass of sarcode, which as quickly assumes the shape and size of the parent. The exuded mass at the same time may be supposed to rapidly secrete a shell ; or, if this is composed of foreign matters, as in the case of a Diffluffia. it may be immediately formed by the adherence of particles to the exuded sarcode. If such shall be proved to be one of the modes of reproduction of the shell-covered Protoplasts, it is one which we may suppose would PEOTOPLASTA— THE LOBOSE PROTOPLASTS. 29 assure comparative uniformity of character in the shape, size, and consti- tution of the shell, just as buds of the same plant ordinarily assure the same varieties of flowers and fruit. On the other hand, reproduction of the Rhizopods from germs or spores would probably furnish a partial explanation of the multitudinous varieties of form. The naked Protoplasts, as represented by species of Amoeba, etc., at times which are apparently related with circumstances unfavorable to activity, even of an opposite character, as extremes of temperature, cold or heat, assume a condition of complete quiescence, reminding one of the winter or summer sleep of higher animals. The condition is preceded by retirement into the deeper part of the ooze in which these lowly creatures live, or by concealment in dirt and* other materials accumulated around and adherent to them. Contracted into a globular form, they are purged of all remains of food and other materials, such as sand, etc., swallowed with the former. They then become gradually invested with a structureless mem- brane consisting of one or several layers, apparently the product of exuda- tion and coagulation of a portion of the protoplasm of the sarcode mass of the body. In this encysted condition, the Protoplast remains an indefi- nite period, and perhaps usually undergoes transformation into reproductive germs or spores. Often, however, if the circumstances are changed for one favorable to activity, the creature bursts its envelope and creeps forth to feed in the ordinary manner, as if it had been passing a time in sleep. The shell-covered Protoplasts are frequently found with, the sarcode mass contracted into a ball commonly defined by a membrane of variable thickness, and apparently due to the coagulalion or condensation of the ectosarc, or of an exterior more clear and homogeneous layer of the soft structure. In the formation of these qu'.3scent balls, they are purged of all remains of the food which is often seen occupying the space between the ball and the mouth of the shell. Frequently, also, in the quiescent or encysted condition of the sarcode, the mouth of the shell is closed by an operculum apparently formed by the accumulation of successive layers of matters discharged from the sarcode ball. The encysted ball of the shell-covered Protoplasts in many instances appears to be resolved into globules, or coarse granules of nearly uniform size, which are probably to be viewed as germs or spores. From the researches of Mr. Carter* it would appear that in Amreba * Auuals aud Magazine of Natural History, xviii, 1856, p. 22G. 30 FEESH-WATEE EHIZOPODS OF NOETH AMEEICA. and Euglypha, representatives of the Lobose and Filose Protoplasts, the endosarc becomes resolved into nucleated cells, which are of the nature of ova, while the nucleus is resolved into granuliferous non-nucleated cells, finally breaking up into their constituent granules, which are of the nature of spermatozoids. AMCEBA. Greek, amoihoa, clianging. FbZi/W; LinnEBus, 1760. C/taos; Lmuseus, 1767. Pj-oieas: MuUer,1786. T^iftHo; Gmeliu, 178S. Amiba: Bory, 1824. Amasba: Ehrenberg, 1831. Animal, when at rest, a spherical or oval mass of soft, hyaline, color- less, homogeneous, pale granular protoplasm, possessing extensile and con- tractile power, and in the active conditiofi devoid of an investing membrane, or any kind of covering. In motion, mostly of exceedingly variable and ever-changing form, and with no absolute distinction of parts, though fre- quently exhibiting more or less disposition to differentiation into an anterior and a posterior region. Ectosarc hyaline, crystal-clear, but, with high mag- nifying power, exhibiting more or less of an infinitely fine granular consti- tution. Endosarc continuous with the former, finely and coarsely granular, mingled with corpuscles of intrinsic and varied character, together with various ingesta, consisting of food, water-drops, sand, etc. Containing also a nucleus and a contractile or pulsating vesicle, or sometimes more than one of either or both of these constituents. Body with no external appendages of a fixed or permanent character. Pseudopods digitate, simple or branching, cylindroid and blunt, or more or less tapering and pointed, or short and broadly lobate, consisting of exten- sions of the ectosarc with variable proportions of the endosarc, or of the former alone. Animal in the quiescent state, purged of food and other ingested mat- ters, globular in form, and invested with a structureless membrane, appa- rently produced by coagulation of a portion of the ectosarc. AMOEBA PROTEUS. Plates I, figs. 1-8; II, figs. 1-13; IV, figs. 22-25; VII, figs. 13-19; VIII, figs. 17-30. Dcr klcine Proteus. Eiisel: Insecteu Belustiguug, 1755, iii, 621, tab. ci. Volvox Chaos. Liunseus : Systoma Naturte, eel. x, 1760, i, 821. Volvox Proteus. Pallas: Elenohua Zoopliytorum, 1766, 417. CMOS Protkeus. Linnseus: Systema Naturaa, ed. 12 et 13, 1767, i, 1326. Vohox Spliarula. Miiller: Verm. Torres. Fluviat. 1773, 31. GENUS AMOEBA— AMOEBA PllOTBUS. ' 31 Protevs diffljwns. Miillcr : Animalcula Infusoria, 1786, 9, tab. ii, figs. 1-12. — Surrixay : Diet. Sci. Nat. 1826. Vibrio Proteus. Gmelin: Lin. Syst. Nat., ed. 13, 1788, 3899. Amiba divergens. Bory: Diet. Clas. Hist. Nat. 1822, 261. Amiba Swaili. Bory: Enoyo. M^thi., Hist. Nat. Zoophytes, 1824, 46. — Dujardin: Hist. Nat. Zoophytes, Infus. 1841, 232. Amiba MUlleri. Bory: Enoyc. Mdth., Hist. Nat. Zoophytes, 1824, 46. Amceba princeps. Ehrenherg: Ahh. Ak. Wis. Berlin, 1831, 28, 79; Infusionsthierchen, 1838, 126, Taf. viii, Fig. X. — Perty: Kenntniss kleinst. Lehensformen, 1852, 188. — Auerhach: Zeitsoh. wissens. Zool. 1856, 407, Taf. xxii, Kg. 1-10.— Leidy: Pr. Ac. Nat. So. 1874, 14,143. Amiba princeps. Dujardin: Hist. Nat. Zoophytes, Infus. 1841, 232, pi. i, fig. 11. Amoeba ramosa. Fromentel: Etudes Microzoaires, 346, pi. xxviii, fig. 2. Amwba communis. Duncan: Pop. So. Review, 1877, 233. Amooba chaos. Leidy: Pr. Ac. Nat. Sc. 1878, 99. Amooba proleus. Leidy: Pr. Ac. Nat. Sc. 1878, 99. Species comparatively large, nearly colorless, or more or less black by transmitted light, pale yellowish by reflected light; spheroidal or ovoidal when at rest; very variable and ever changing in shape when in motion, ordinarily ramose,. palmate, or radiate; comparatively active, creeping, with a disposition to differentiate into an anterior and a posterior region. Pseu- dopods digitate, simple or branching, and blunt, sometimes tapering and pointed. Posterior part of the body in contraction receding in the advan- cing pseudopods, sometimes assuming a mulberry -like appearance. Nucleus usually single, discoid, habitually posterior. Contractile vesicle usually single and large, habitually behind the former. Ectosarc thinly differen- tiated. Endosarc finely and coarsely granular, with many and varied ele- ments, contributing in its flow to the extension of the pseudopods. Size, in the globular form to 0.2 mm.; in the ovoidal form to 0.3 by 015 mm. ; extended in a dendroid form, occupying a space of 6.5 mm. in length by 0.4 mm. in breadth; in a palmate form 0.5 mm. long by 0.35 mm. broad; in a radiate form from 0.2 mm. to 0.5 by 0.4 mm. ; in an irregularly cyHndroid form to 1 mm. long. The largest observed occupied a space of 0.6 by 0.2 and 0.35 mm. Locality. — Common in the superficial ooze of ponds and ditches almost everywhere, though rarely in large numbers. Ditches below Philadelphia and brick-ponds in the vicinity. Ponds in the neighboring counties, including Delaware, Che^ster, Montgomery, Bucks, Berks, and Northamp- ton; Broad Mountain, Schuylkill County; Pokono Mountain, Monroe County, Pennsylvania; at Absecom, Hammonton, Woodstown, Vineland, Cape May, and other places in New Jersey; Newport and Narragansett, Rhode Island ; and lakes of the Uinta Mountains, Wyoming Territory. A large Ai»«Bba is the subject of the earliest notice of a Fresh-watei 32 FEESH-WATEE EHIZOPODS OF NOETH AMEEICA. Rhizopod. It was discovered by Rosel, and described in a work entitled "Insecten Belustigung ", or Recreation among Insects, published in Nurn- berg in 1755. Rosel calls the animal the little Proteus, and accompanies his description with nineteen well-executed and colored figures engraved by himself. Linnaeus, in the Systema Naturae, referring to Rosel's animal, named it Volvox Chaos, and subsequently Chaos Protheus. Pallas called it Volvox Proteus. Miiller afterwards named it Volvox Sphcerula, but later, after having himself observed the animal, described and figured it under the name of Proteus diffluens. As the generic name of Proteus had been previously appropriated for the well-known Salamandroid of Adelsberg, Bory de St. Vincent substituted that of Amiba for the animal of Rosel and Miiller, calling it by the various names of Amiba divergens, A. Boesili, and A. MuUeri. Ehrenberg, in the Transactions of the Academy of Sciences of Berlin for 1830, indicated and figured a comparatively small Amoeba, the ^^th of a line (pp. 39, 75, pi. I, figs. 5), under the name ,of Amoeba diffluens, regarding it as the same as the Proteus diffluens of Miiller. In the Transactions of the following year, Ehrenberg described what he considered to be a new species with the name of Amosba princeps. The characters given of this are as follows : Diameter ith of a line ; body trans- parent, yellowish, with many easily and voluntarily movable blunt pro- cesses; four times larger than the Proteus. This description is accompanied with one of Amoeba diffluens (Proteus diffluens, Miiller), as follows: Diameter Jjtli of a line; body transparent as water, mostly with only three or four variable processes; four times smaller than the preceding species. In his great work, the Infusionsthierchen, 1 838, Ehrenberg described Amo^a princeps as '"large, yellowish, equalling Jth of a line, provided with a variable number of cylindrical appendages, thick and rounded at the end." The accompanying figures (Taf VIII, Fig. X) accord with the description, and agree with the familiar common large Amoeba. In the same work, Amoeba diffluens is described as "rarely surpassing the ith of a line, hyaline; processes variable, moderately long and robust and suba,cute." Under this species, Ehrenberg places as synonyms the GEmiS AMCEBA— AMCEBA PEOTEUS. 33 names of all forms of Amoeba previously described by others, including the one first discovered, the little Proteus of Rosel. In the earlier description of Amoeba princeps, Ehrenberg says it is four times larger than the Proteus, meaning the Proteus diffluens of Miiller and his own Amoeba diffluens, but not the Proteus of Rosel ; for this, according to the actual representation of the latter, is four times larger than Amoeba princeps, and sixteen times larger than Amoeba diffluens, according to the measurements of these given by Ehrenberg. In the remarks on Amoeba princeps, in the Infusionsthierchen, Ehren- berg says " it is true that Rosel described a larger species of Proteus of which the dimension accords with this, but the blunt processes, of the species occurring in Berlin, do not agree well with those of Rosel's figures, but rather approximate those of larger individuals of Amoeba diffluens." It is natural to suppose that an Amoeba discovered by the earliest microscopic observers would be one of the more common large forms, and that such was the case appears to be fairly proved by figures and descrip- tions. Rosel, in referring to one of his figures of the little Proteus, remarks that in its natural size it looked like A. Now, this figure A represents the animal in its quiescent state, in globular form, and the figure measures just four fifths of a line. No Amoeba has since been recorded, in the same condition, so large as this, and it is not unfair to suppose that the figure is somewhat exaggerated, which could readily occur in absence of the accurate means of measureinent which came subsequently into use. Rosel refers to his having held his little Proteus at rest with a pointed feather, which is alone sufficient to prove that he had under his observation one of the largest forms of Amoeba. In size, according to the actual measurements given, Rosel's Proteus is as much larger than Amoeba princeps as this is than Amoeba diffluens. In all other characters ascribed by Ehrenberg to Amoeba princeps, it appears to the writer to agree with the Proteus of Rosel, and this without doubt better than does the Amoeba diffluens as described by Ehrenberg. Amoeba princeps is said by the latter to be yellowish, while the Amoeba diffluens is said to be clear as water. Though Rosel says nothing of the color of the Proteus, his figures, carefully colored, exhibit the granular 3 BHIZ 34 FRESHWATER RHIZOPODS OF NORTH AMERICA. contents yellowish, and the exterior investment colorless, just as our large common Amoeba appears under partially reflected and transmitted light. Most of Rosel's figures exhibit the characteristic changes of form of the Proteus, and these certainly agree with those of our common large Amoeba, and better with those of Ehrenberg's figures of Amoeba princeps than with those of the same author's figures of Amoeba diffluens. Of the figures of Rosel, one he likens in its branching to the antler of a deer, a resemblance which all must have seen who are familiar with the large Amoeba commonly regarded as the Amoeba princeps. As regards both size and color of the Proteus of Rosel, it might refer to other large Amoebse than A. princeps, as for instance the A. villosa of "W*allich, or the Pelomyxa palustris of Greeff ; but the changes of form and the extension and shape of the pseudopods rather approximate it to the former. Miiller's description and figures of Proteus diffluens, which that author regarded to be the same as Rosel's Proteus, appear to apply to the same animal as Ehrenberg's Amoeba princeps, rather than to the Amoeba diffluens of the latter. From the review thus presented, I think it will be admitted that the little Proteus of Rosel, the Proteus diffluens of Miiller, the Amoeba princeps of Ehrenberg, and our large familiar Amoeba, are to be regarded as one and the same animal. It has been suggested that all forms of Amoeba may eventually be found to be transitory phases of the same species ; but even this view does not render the determinations of Ehrenberg and those who follow him in relation to Amoeba princeps and Amoeba diffluens any the less incorrect. Having arrived at the conclusion that our common large Amoeba, usually called Amoeba princeps, is the same as Rosel's Proteus, the question arises as to its appropriate name. Ehrenberg changed the name of Amiba of Bory into Amoeba ; and had it not been that the latter mode of spelling the word had come into such common use, I would have dropped the ugly diphthong, and resumed the word Amiba, as employed by Bory and Dujardin. Of the specific names employed for the little Proteus, that of chaos in Volvox Chaos of Liunseus is oldest ; but that of proteus in Volvox Proteus of Pallas appears more appropriate, and would at the same time serve to GlENUS AMCEBA— AMCEBA PEOTEUS. 35 perpetuate the name given to the animal by its discoverer. I therefore suggest that the name of Afnoeba proteus should be employed for the common large. Amoeba, recognizable as the Proteus of Rosel and the Amosba princeps of Ehrenberg ; otherwise, according to the strict rules of scientific nomenclature, it should be Amoeba chaos. Amceba protieus (pis. I, II) is one of the largest forms of the genus, and is the one which is perhaps the most familiar to those who are accustomed to the examination of the microscopic life abounding in fresh waters. It is commonly found in the superficial ooze of clear and comparatively (fuiet waters, such as ponds, lakes, and ditches. It also occurs among Duck-meat and on the under surface of leaves of aquatic plants floating on the surface of water. In some instances, in certain localities, it may be found in profusion; but frequently in similar places, or even at other seasons in the same place, I have failed to obtain it after the most diligent search. Specimens often vary, especially in dififerent localities, to such a degree that it is difficult to decide whether to regard them as really pertaining to this or some other described species. The habitual appearance of characteristic forms as they have come within my notice may be ^iescribed as follows : The Amceba, if observed immediately after having been transferred from the material in which it lived to the object-glass of the microscope^ appears as a globtilar or ovoidal, granular ball, translucent and of a blackish hue by transmitted light, or faintly yellowish white by reflected light. Often, however, from the first moment of observation, the animal appears of irregular shape, with projected pseudopods already in movement, apparently as if it had been little affected by disturbance. The globular or ovoidal quiescent Amceba after a little while puts forth from ever}?^ part of the body a multitude of clear, rounded extensions of the ectosarc, which give one the impression that the creature had sud- denly exuded, or, if I may use the term, sweated, numerous drops of liquid. These quickly elongate, and assume the form of digitate pseudopods, in which, condition the animal may present the appearance seen in fig. 1, pi. I. A number of the pseudopods continue to elongate and become thicker, not only .from an extension of the ectosarc, but by the attendant influx of the endosarc. The greater number of the pseudopods originally seen are 36 FEBSH-WATEE EHIZOPODS OF NOETH AMEEICA. withdrawn and altogether disappear. The growing pseudopods are cyHii- drical or digitate, with bkxnt extremities. They extend in all directions, are usually more or less curved, and frequently branch. In thi& condition, the Amoeba may present the appearance represented in fig. 2. Occasionally the rounded or ovoidal mass composing the body of the Amoeba, after putting forth numerous processes in the manner above described, withdraws the most of these, while a few others rapidly elongate, and diverge on each side, and the animal may assume a shape reminding one of a great spider. A specimen in this condition is represented in fig. 1, pi. II. Commonly, while one or two, and occasionally more, of the pseudo- pods, continue to extend and branch, others shorten and disappear, and the principal mass of the body is diminished at the expense of the growth of the advancing pseudopods, and it may to a greater or less extent merge into them. As the Amoeba advances through the extension of one or more prin- cipal pseudopods in a particular direction', the whole together becomes more or less differentiated into an anterior and a posterior region. The posterior extremity of the body, in its contraction through the flow of its endosarc into the advancing pseudopods, frequently assumes a more or less mammil- lary appearance. In this condition, the Amoeba, in its form and branching, may remind one of the antler of an elk, and such specimens are represented in figs. 3, 4, pi. I. In the continued extension and branching of one or more of the chief pseudopods, the Amoeba progresses more or less rapidly, the body appear- ing incessantly to exhaust itself in the continued growth or elongation of the pseudopods and in the production of new ones, while it is as incessantly replenished by the contraction and melting-away of pre-existing pseudo- pods. While the animal moves along, its direction may change at any moment by the more active prolongation of any one of the pseudopods. The changes of form produced by the extension and branching of cer- tain of the pseudopods, with the recession, melting-away, and total disap- pearance of others, is endless. Sometimes the animal creeps onward in a flowing manner with comparatively simple cylindroid form, occasionally emitting a single pseudopod, on one side or the other. More commonly in movement it assumes a dendroid or palmate form, or sometimes, diver- ging from the directly onward course, it becomes more radiate in appearance. GENUS AMOEBA— AMCEBA PEOTEUS. 37 Not infrequently it assumes more or less grotesque shapes, in wMcli almost every conceivable likeness may be imagined. Usually Ammba proteus creeps along surfaces, mainly extending its psQudopods, and advancing in the same general direction. The pseudopods may, however, be extended or produ '^'Q ^ ^^ %Jl y 2 \/ 3 M f-\-4 ^ s Pelomyxa villosa; mode of motion. At times, Felomyxa villosa will appear stationary, or nearly so, and comparatively quiescent, and will project from any part of its surface, slowly or more or less rapidly, a variable number of narrow, conical, or somewhat spindle-shaped, pointed pseudopods of clear ectosarc, as seen in figs. 3, 5, 10. These receive none of the endosarc, and are not used as locomotive organs, but perhaps serve a tactile function. I have not observed Pelomyxa villosa assume the branching condition of Amcsba proteus, but under undue pressure I have seen it project one or more long digitate pseudopods, as in the latter. The villous area or appendage of the Pelomyxa under consideration resembles that ascribed to Amoeba villosa by Dr. "Wallich. In the resting *Annals and Magazine of Natural History, 18G3, xi, 370. GENUS PELOMYXA— PELOMTXA VILLOSA. 77 condition or spheroidal form of the animal it is not obvious, and it appears to be capable of complete retraction and obliteration, as is the case with the ordinary pseudopodal extensions. It is variable in appearance, though as ordinarily seen it forms a discoid or sucker-like process defined from the rest of the body by a constriction. When not projected, it is sometimes visible as a circular patch terminating the posterior extremity of the body, as represented in figs. 1, 13. Sometimes the process appears as a conical or irregularly papillary projection. The villi are very variable; sometimes numerous, minute and crowded; sometimes fewer, thicker and widely separated; at times short and papillory, at others more or less long and hair- like, and occasionally branched. See figs. 1-10, 12, 13, 15-17. The villous portion or process of the body is highly prehensile, and serves the animal to fix its position in like manner with tbe sucker of a leech. At times when I have poured off the liquid from tbe glass on which I was examining a specimen of the Pelomyxa to put on it clearer water, it would maintain its place by means of the villous end of the body. As a temporary organ of prehension it is no doubt of importance in obtaining food. Algae and other materials are often seen adherent to and dragged along after it in the progressive movements of the animal, as represented in fig 14. In structure, the villous process appears as an extension of finely granular homogeneous endosarc without the slightest differentiation of enclosing ectosarc, and when it is of iri-egular or papillary form it looks as if it were a sort of hernial protrusion of the endosarc through an accidental rupture of the ectosarc. Sometimes the villous area of Pelomyxa villosa appears only as a villous fringe to the posterior extremity of the body. Occasionally I have observed an individual emit a multitude of minute villi near or in conjunction with the usual villous area, or in other positions of the body. These addi- tional or supplemental villi appeared to be less permanent than the others, or at least after a time they were withdrawn and were no longer visible in the same individual. Pelomyxa villosa I have usually found to be so opaque, except in young specimens, that the different elements of its interior structure are undis- tinguishable without the animal is submitted to considerable pressure, or it is actually crushed. In habit, like the Pelomyxa palustris, it is exceedingly gluttonous, and is remarkable for the manner in which it gorges itself with 78 FKESH-WATEE EHIZOPODS QF NORTH AMERICA. food and other materials of diflPerent kinds. Usually the quantity of the ingesta is so great as totally to obscure from view all the intrinsic consti- tuents of the endosarc except when they rush into pseudopodal projections of the ectosarc. The food is mainly of vegetal character, consisting of all sorts of algse, especially diatoms, desmids, and other unicellular forms, osciUarias and other filamentous forms, fragments of higher plants, fibres and particles of wood and leaves, etc., besides flocculent, apparently decaying, vegetal matter. The food in the interior of the animal, as in other amoeboid forms, when of soft or yielding character, appears as variously colored balls, mostly yellowish, brownish, or green, often enclosed in water-drops, but often also free from the latter, as indicated by the absence of the clear zone, which usually indicates the presence of surrounding liquid. Much of the food apparently is diffused, as fine yellowish matter, among the intrinsic granu- lar constituents of the endosarc. In the ordinary process of digestion in Pelomyxa villosa, as in other amoeboid forms, green vegetal substances gradually assume a yellowish or brownish hue. The insoluble residue of the food of all kinds is from time to time discharged in the usual manner at the posterior extremity of the body, but whether through or to one side of the villous process I did not ascertain. Quartz-sand is a frequent and abundant material mingled with the food and other constituents of the endosai-c. Not only fine but coarse particles are swallowed, but they appear always to be directly in contact with the granular and other matters of the endosarc, and not contained in vacuoles or water-drops, as ordinarily is the case with most solid food. In many individuals, the quartz-sand has appeared to predominate over everything else in the endosarc, and such specimens, which were literally bags of sand, I formerly described as a species, with the name of Amoeba sabulosa. Pelomyxa palustris, as described by Prof. Grreeff, also swallows a nota- ble quantity of sand ; but this appears not to be the case, at least to any remarkable extent, with Amoeba villosa, as described by Dr. Wallich and Dr. Duncan. Dr. Wallich describes crystals of rhombohedral form as a constituent of the endosarc of Amoeba villosa; but these bodies, ordinarily so conspicu- ous and common in Amoeba proteus, either do not exist, or they escaped my GENUS PELOMYXA— PELOMYXA VILLOSA. 79 notice, in the more characteristic or matured specimens of Pelomyxa villosa. In some young amoeboid forms, which I suspected to pertain to the latter, crystals undoubtedly existed, and perhaps they are likewise abundant enough in mature forms, but ordinarily are obscured from view by the presence of the large proportion of sand particles. Prof Greeff does not mention them as an element of Pelomyxa palustris-. The basis of the endosarc of Pelomyxa villosa, as in the latter, consists of a pale and finely granular protoplasm, mingled with more distinct fine oil-like molecules. Besides the food materials and other ingesta, the endo- sarc contains a variety of other elements. Among these there are variable proportions of clear vacuoles, sometimes numerous, sometimes few, of dif- ferent sizes. Another element consists of clear or indistinctly granular corpuscles of albuminoid or oleaginous appearance, mostly colorless, but sometimes more or less feebly yellowish. They range from a small size up to 0.006 mm., though the prevailing size was about one-half this dimension. Under the action of acetic acid they mostly remained unchanged, though many became more distinctly granular, and less distinctly outlined. These corpuscles probably correspond with the 'sarcoblasts' of Amoeba villosa of Dr. Wallich, and the 'Glanzkorper' or shining corpuscles o£ Pelomyxa palus- tris of Prof Greeff. Mingled with the clearer corpuscles just indicated, there were others, comparatively fewer, and measuring about 0.004 mm. These were more or less homogeneous, with scattered granules superficially situated. Still other corpuscle^, about the same size as the preceding, were finely granular, and contained a darker granular nucleolus. I am uncertain whether these corpuscles correspond with the nuclei o£ Pelomyxa palmtris as described by •Prof Greeff. In some crushed specimens of the variety of Pelomyxa villosa, origi- nally noticed by me under the name of Amoeba sabulosa, I further noticed a few comparatively large granular spheres reaching about 0.016 mm., and containing each several scattered nucleoli, some of which appeared clear and homogeneous, while others were granular. In several instances, in crushed specimens of Pelomyxa villosa, I also observed, as one of the constituents of the endosarc, numerous minute rods, from 0.001 to 0.005 mm. in length, and resembling vibrios, but motionless 80 FEESH-WATEE EHIZOPODS OF NOETH AMEEICA. Under the j^th inch objective power of the microscope, many appeared to be transversely striated. Similar bodies are described by Prof. GreefF as a constituent of the endosarc of Pelomyxa palustris. Dr. Wallich describes a conspicuous nucleus and an equally conspicu- ous contractile vesicle as present in Amoeba villosa, having the same essential characters and holding the same habitual position as in Amoeba proteus. In the figures accompanying Dr. Wallich's memoir, the single large nucleus, and the large contractile vesicle, or in its place several smaller ones, are among the most striking features of the creature. In Pelomyxa villosa, except in those specimens I have regarded as young individuals, I have at no time been able to detect a single large nucleus like that represented in Amoeba villosa, or such as exists in A. proteus. I have, also, at no time observed a single large and conspicuous contractile vesicle in the more characteristic forms of the animal; but in its place there are usually from one to half a dozen small ones, commonly occupying a position in the vicinity of the villous area of the body, or even partly within this area when it is produced as a process. Frequently the small contractile vesicles are more or less obscured from view by other surround- ing elements. They commonly remain separate and independant of one another, and while one appears and undergoes enlargement another collapses and disappears. I have not been able to trace a continuation of the history of Pelomyxa villosa. In one instance I observed a large individual replete with quartz-sand, apparently burst and scatter its softer granular constituents until reduced to about one-half the original size. The remaining portion of the body appeared unhurt, but what the phenomenon meant I did not positively ascertain, though I suspected that it was attendant upon the expulsion- of ■ germs. DINAMCEBA. - CKen found under favorable circumstances, is usually observed gorged with food. It appears mainly to feed on algae, and its favorite food consists of the common desmids Didymoprivm grevillii and Bamhusina hrebissonii, especially GENUS DINAMOEBA— DINAMCEBA MIEABILIS. 85 the former. Where these two desmids thrive luxuriantly, in ponds of the deep sphagnous and cedar swamps of New Jersey, I have found the favorite haunts of Dinamoeba. Less frequently among its food contents I have observed diatoms, closteria, and the brownish flocculent matter common in some of the ponds indicated. The green spots so generally observed in Dinamceba are mostly due to the presence of scattered cells of Didymoprium and less frequently of Bambusina, scattered as food contents through the endosarc. As a result of digestion, the green endochrome of the desmids loses its color, at first becoming paler and then yellowish green, then ochredus yellow. The discharged cells of the desmids appear with the yellow shriveled remains of the endochrome in the centre. The figures of pi. VI represent individuals of Dinamoeba, feeding on Didymoprium, and containing in their interior multitudes of food-balls mainly consisting of joints of that plant, of various shades of green, and others rendered brown or yellow as the result of digestion. As is intimated, by Prof Duncan, to be the case in Amoeba, I suspect that Dinamceba habitually takes its food at the posterior part of the body. I have not seen the animal in the act of seizing its food, so that I am unable to say whether it does so through the aid of the terminal papillae. My observations, however, lead me to believe that in swallowing the food it first enters to either side of the papillary extremity. In one instance in which I detected Dinamoeba in the act of swallowing, the animal presented the appearance represented in fig. 1, pi. VI, and had been but a few minutes previously transferred to the animalcula-cage. It was a fine vigorous specimen, broadly oval, 0.18 mm. long by 0.16 broad, with its characteristic subulate pseudopods projecting in every direction. All parts bristled with spicules, and the body was enveloped in its hyaline jelly-cloak. A long filament of Didymoprium had one end bent and swallowed by the Dinamceba, entering from the front, on the left side, in advance of the middle. At the position of entrance it wasVeiicIosed for some distance by a thick papillary protrusion of clear ectosarc, which clasped it so tightly as to constrict the jelly-envelope of the Didymoprium completely through to the cellular axis of the plant. A little later the animal slowly expanded so as to measure 0.24 mm. in length, and retaining the original breadth. At the same time, the Didy- 86 FEESH-WATBE EHIZOPODS OF NOETH AMEEICA. moprium was broken, the detached portion pushed off, and the retained portion drawn in, and with this the large papilla of ectosarc. A moment after, a large protrusion of the body occurred to the left of the posterior extremity, followed by an abrupt discharge from it of twenty -four cells, mostly of Didymoprium, with a few of Bambusina. The discharged cells contained the yellow shriveled remains of the endochrome. A view of the animal in the condition just described is represented in fig. 2. Later, as the animal slowly glided along, it presented the appearance seen in fig. 3. The body was depressed pyriform, with the posterior nar- row end crowded with long papillae. In this condition it measured 0.28 mm. long. Eight hours subsequently, the same individual measured 0.24 mm. long by 0.16 mm. broad. In another instance I observed an active, well-fed Dinamoeba in the act of swallowing a filament of Bambusina. The successive steps of the process are represented in the woodcuts 1-12. Successive changes ol)serve(l in Dinamoeba mirabiUs while in the act of swallowing a filament of tlic alga Bambusina. The arrows indicate the course of movement in the swallowing of the alga. When first seen, the animal was oval, 0.22 mm. long by 0.16 mm. broad. The alga was 1.12 mm. long, and a portion of it was immersed in the Dinamoeba, entering to the left of the posterior extremity, and extend- GENUS DINAMCEBA— DINAMCEBA MIRABILIS. 87 ing along the left side, the fore end causing a sHght protrusion of ectosarc at the head (1). A little later the animal slightly elongated, remaining of the same breadth (2). Gradually moving with an inclination to the left, the relative position of the alga was changed so that it crossed in a slant, sind the anterior end protruded to the right of the hea^d (3). The relative position of the alga continued to change, so that it became trans- verse (4), then gradually slanted in the opposite direction (5), and at last assumed nearly its original position, as seen in cut 6. It next acquired a median position, extending through the length of the animal, as seen in cut 7. The creature now extended in both directions along the alga, as repre- sented in the succeeding woodcut (8), until it became 0.36 mm. long by 0.128 broad. The movements up to this moment had been slow and uniform, but now the animal rather suddenly doubled upon itself, bending the alga with it, as seen in cut 9. The two extremities of the alga were bent more closely together iintil they were parallel, and their ends pro- truded together from the same pole of the animal, as represented in cuts 1 0, 1 1 . In this condition the animal measured nearly the same as origi- nally, that is, 0.24 mm. long by 0.16 mm. broad. Subsequently the right extremity of the alga was drawn into the animal, leading but one protruded, as seen in cut 12, and after a little while this also disappeared, and the animal moved away, with the lower part, as seen in the woodcut, in advance. As the alga was three times the length of the animal after it was swallowed, it must have formed a coil; but this was entirely obscured from view by the abundance of food and other constituents of the endo- sarc. During the process of swallowing the al^a, as may be noticed in the outline figures, the number and position of the pseudopods incessantly varied, In the beginning they were numerous; at one time none, and later but two or three. From the creature doubling upon itself, in the manner represented, it would seem as if the head and papillary end of Dinamoeba were not permanently differentiated, for both subsequentiy appeared together to become the tail end, while an intermediate portion of the body assumed the relative position of the head. Indeed, no portions of the exterior of Dinamoeba are constant, although they usually seem to be so. Head and tail appear to be mutually interchangeable, and such also is the case with the processes I have for convenience distinguished as pseudopods and papilla. 88 FEESH-WATEE EHIZOPODS OP NORTH AMEEICA. Some hours later, on examining the same Dinamceba, which had been preserved in the animalcula-cage, it presented the appearance represented in fig. 6, pi. VI. It was oval in shape, 0.272 mm. long by 0.16 mm. broad, and sitting, as it were, on a Didymoprium. From the head projected a num- ber of pseridopods. The posterior extremity clasped the alga by means of a transverse cylindrical process of greater length than the breadth of the body. The ends of the process on each side were extensions of the ectosarc fringed with papillae. The cylinder embraced the alga so tightly as to contract its gelatinoid sheath close to its green cellular axis. While watching the Dinamcfiba, without any suspicion of what was to follow, and with the impression that the animal was holding a resting position, as seen in the woodcut 13, the Didymoprium suddenly broke within its clasp, as represented in the following woodcut 1 4. Successive changes observed in Dinamceba miraMUs while in the act of swallowing a fila- ment of the alga Didymoprium. The animal subsequently passed, through the successive changes seen in cuts 15-21. The Dinamceba gradually shortened, the pseudo- pods in front diminished to two, the two portions of the alga were made to approach each other, and the right side of the body projected in a nipple-like prominence, from which there were suddenly discharged upward of twenty cells of Bambusina (15). These were probably derived from the filament swallowed, as previously described. The cells were nearly all separated, and contained only the shriveled remains of the endochrome. The Dinamceba again became elongated, all pseudopods disappeared, GENUS DINAMCEBA— DINAMCEBA MIEABILIS. 89 and the two portions of the alga approached so as to project from the ani- nxjal at an acute angle, while at the same time the right portion was observed slowly to sink into the interior (16). The animal next turned to the left, the two portions of the alga assumed a position at a right angle, and the left portion broke into two (17). The animal then turned until the head was directed backward, and the two portions of tlie alga remaining in connection with the animal assumed a parallel position dose together on the left of the tail end (18). What had been the left portion of the alga sunk gradually" into the body and disappeared (19). ' Subsequently what had been the head of the animal shrunk and became the tail end furnished with pseudopocls, while the previous tail end projected pseudopods and moved in advance as the head end (20). The projecting extremity of what had been the right portion of the alga broke off close to the animal and was rejected (21), while the retained portion sunk out of sight. Some days later I. had the opportunity of observing another Dinamoeba in the condition represented: in fig. 4, pi. VI. It was a. fine, large, specimen, of ovate form, the third of -a millimetre, long by the fifth of. a millimetre broad. From the left of the posterior part of the body projected two .divi- sions of a Didymoprium, which no doubt had been- broken apart, as in the former instance. The two divisions of the alga assumed a symmetrical position at the tail end, and afterward portions of each were successively broken off, and the retained pieces were swallowed. Habitually Dinamoeba rejects excrementitious matters at one side of the posterior papillary extremity ; but I have repeatedly observed the animal discharge the remains of food not only from other parts of the body, but in two or three widely separated positions at once, as represented in fig. 7. Though Dinamceba miraUlis is a more sluggish animal than Amoeba proteus, it appears to be more irritable. Disturbance generally causes it to withdraw its pseudopods and contract its body, though slowly. A slight shock, I have also noticed, will frequently cause it to discharge a portion of its food contents, and this several times and at several points at once. An active specimen of Dinamceba, from Atco, New Jersey, when first noticed, was oval, 0.3 mm. in length by 0.2 mm. in breadth. After a moment, from disturbance, it discharged a few cells of Didymoprium, at the same -time, from the right of the head and the left of the tail, and in a few seconds afterward upward of twenty cells of the same alga from the 90 FEESH-WATER EHIZOPODS OF NOETH AMEEICA. former position, and a series of four cells, still connected together, from the latter position. The animal then became globular and quiet, and measured 0.2 mm. in diameter. On the same occasion, in the same drop of water, I observed another fine Dinamceba, with an oval body 0.25 mm. long by 0.2 mm. broad, with numerous subulate pseudopods projected in all directions. It exhibited a thickly papillose tail-like appendage 12 mm. long by 0.06 mm. broad. The tail was filled with fine granular matter, a multitude of darkly defined oil-like molecules, clear globules, and three cells of Didymoprium. The animal afterward discharged a group of cells of the latter alga from the body to the left of the tail, and subsequently assumed a long clavate shape 0.4 mm. long by 0.18 mm. broad at the thicker end. In one instance I observed a Dinamceba, which contained, with other food, a desmid, the Closterium didymotocum, as represented in fig. 1, pi. VII. When first seen, the alga held a transverse position causing a considerable protrusion of the body on the left side. The alga had evidently been seized. just after it had parted from another; — ^for one-half of the cell was comparatively tender and doubled upon the older and more rigid half. With the Closterium, smaller algae, and other ordinary materials, there was an unusually large vacuole, which discharged itself several hours after first observing it. About eight hours after seeing the Dinamceba, the minute spicules of the surface had disappeared, and two hours later the Closterium was discharged, but without my having seen the act. The following morn- ing the animal presented the appearance represented in fig. 2. It was 0.21 mm. long by 0.12 mm. broad at the fore part. The pseudopods were remark- ably long, up to 0.12 mm., and projected in every direction. The posterior extremity ended in a number of compound papillae. The endosarc, besides colored food-balls, contained a multitude of colorless globules. Three smaller ones of these appeared within the tail end as contractile vesicles. No trace of the minute spicules, usual in Dinamceba, was to be seen on any part of the surface of the animal. In the Proceedings of the Academy of Natural Sciences for 1874, page 167, I described an amoeboid, under the name of Amoeba tentaculata, as follows: Body spheroidal, oval, or limaciform, projecting a multitude of long conical or fusiform pseudopods of clear ectosarc,. into which no gran- GENUS DINAMCEBA— DINAMCBBA MIEABILIS. 91 ules of the endosarc enter ; posteriorly finely papillate, or with a discoid papillate subdivision. Exterior of the body colorless and transparent; interior yellowish and spotted brown or green from the food contents. When moving, the animal resembles a sea-slug, Eolis, in its shape and from its many long pointed pseudopods. At the fore part of the body, in pro- . gression, a large extent of perfectly clear ectosarc precedes the endosarc, equal to about one-sixth of the length of the body. This is blunt in front, and with its divergent pseudopods resembles the head of a slug. When floating, the animal looks like a large Actinophrys with thick conical rays. This amoeboid, which I now suspect to represent only another condition or stage of Dinamoeha mirabilis, I have repeatedly found, in the autumn, in the same localities. It agrees in habitual shape and size, in the kind of pseudopods, and the possession of the posterior papillary organ, with the more characteristic form. We have seen that both the minutely spiculate condition of the surface and the gelatinoid coat of Dinamoeba may be dis- pensed with, so as to reduce it to the condition of the amoeboid form under consideration. This amoeboid seems as if it were Dinamoeba which had passed the actively feeding stage, as it contains but comparatively little food and the endosarc is much reduced. The large proportion of ectosarc in relation with the endosarc reminds one of Amoeba verrucosa. In motion, the creature advances slug-like in manner and general appearance. The body is composed of a central mass of granular endo- sarc enveloped with a thick layer of clear ectosarc, of which a still thicker portion forms the head, as seen in figs. 5, 7, and 10, pi. VII. The pseudo- pods, usually numerous, form subulate processes of clear ectosarc occu- pying mostly the anterior region of the body. The posterior papillae are variable in number and size, and in advance show more or less disposition- to merge into pseudopods. Figs. 5-7 represent three successive views of the same individual as observed at intervals during thirty-six hours. As first seen, fig. 5, it was elongated elliptical with prolonged blunt poles, both of which, as weU as the exterior layer of the intermediate body portion, appeared to be com- posed of clear ectosarc. The central mass of granular endosarc was mingled with difi'used brownish material, and contained a few clear globules or vacuoles, various articles of food, and a large pale granular nucleus 92 FEESH- WATER RHIZOPODS OF NORTH AMERICA. surrounded by a clear halo. Pointed conical pseudopods of clear ectosarc projected everywhere from the head and body, while the tail was minutely and profusely papillose. When next examined, the animal appeared as in fig. 6, oval in outline, with the anterior half covered with pseudopods, and the posterior half with numerous short blunt papillae. The nucleus was concealed from view. Later the body was elongated, with the posterior part most expanded, as in fig. 7. The nucleus was nearly central and quite distinct. In the first and last views, several small contractile vesicles were observed at the posterior extremity of the animal. Among the articles of food there was a long colorless thread, appar- ently a cotton or ligneous fibre, coiled among the other constituents of the endosarc. A bright green desmid, as seen in figs. 5, 6, finally assumed a brown hue, as seen in fig. 7. Fig. 8 represents an individual of the same kind as the preceding, in the act of floating or swimming. The body of globular form, and with numerous pointed pseudopods radiating in all directions, gave it the general appearance of a Heliozoan, except in the character of the rays. The usual posterior papillae did not appear in this condition, but subsequently were seen, when the animal assumed the elongated creeping position. The size of the central body was ranch, reduced in its proportions, from the multi- tude of pseudopodal rays, and measured 0.065 mm. in diameter. The endosarc of the amoeboid under consideration is usually pale gran- ular, and apparently mingled with brownish matter, which I have suspected to be derived from the brown flocculent material usually so abundant in the locality in which the creature is found. It also contains variable pro- portions of fine oil-like molecules, water-vacuoles, brownish and colorless granular food-balls, diatoms, and other food materials, but rarely a particle of quartz-sand. Mostly the fine oil-like molecules are very few or are altogether absent, and frequently also water-vacuoles appeared not to be present except in the nature of contractile vesicles. Of these there are apparent a variable number situated within the villous extremity of the body, often small and comparatively numerous, at other times few and larger. Commonly a nucleus may be detected in the movements of the animal, as seen in figs. 5 and 7. It is of large size, pale granular, and surrounded by a clear ring. In fig. 10, an individual is represented, in which the GENUS DIKAMCEBA— DINAMCEBA MIEABILIS. 93 nucleus appeared to be a sphere containing large granules of uniform size. The specimen was quiet, remained nearly stationary, and occasionally emitted here and there a small conical pseudopod. In a similar specimen the nucleus presented the appearance of including exceedingly dehcate coiled filaments, but the time did not permit me to investigate further the nature of these. Dinamaeha mirabilis, in size, habitual form, and some other characters, approaches Pehmyxa villosa, and after recognizing ^wfl?&a tentaculata as representing another stage of the former, I began to suspect that it might likewise be the same. When, however, we take into consideration the usual abundance of pseudopods in Dinamoeba, their paucity or absence in Pelo- myxa villosa, the difference in the character of the villous and papillary processes, and the difference in habits, with other occasional pecuUarities, we may regard them as distinct unless further investigation shall prove otherwise. JDinamoeba mirabilis bears considerable resemblance to Mastigamceha aspera, described by Prof. Schulze.* This animal is broad, fusiform, about 0.1 mm. long, provided with many pseudopods and a general investment of minute bacteria-like bodies, but is particularly distinguished by the possession of a long flaipellum, projecting in front, from an ovate corpuscle enclosing a nuclear body. When I first saw the figure of Mastigamceha, it occurred to me th9,t Dinamoeba was the same, and that the flagellum in the latter had inadvertently escaped my notice. I waited rather impatiently until the following season, that I might again have the opportunity of exam- ining what I had described as Dinamoeba. I have since seen an abundance of specimens in a variety of conditions ; but in none did I ever see a flagellum. Dinamoeba further differs from Mastigamoeba in other respects : in the habitual form of the body; in the pseudopods, which are digitiform in the latter ; and in the relative position of the minute spiculate bodies investing the animal, which in Mastigamoeba are described as generally placed parallel with the surface. Dinamoeba seems also quite distinct from Bactylosphcerimn vitreum of Hertwig and Lesser,! which appears to be related with Mastigama^a aspera, * ArcMv f. mikroskopische Anatomie, 1875, 583, Taf. xxxv. t Archiv f. mikroskopische Anatomie, 1874, Sup. U, Taf. ii, Fig. 1. 94 FEESH-WATEE EHIZOPODS OF NOETH AMEEICA. but, like the former, is devoid of the flagellum. Dactylosphserium is a smaller animal than Dinamceba, of irregularly rounded form, and from 0.012 to 0.06 mm, in diameter. The pseudopods projecting in all directions are somewhat conical and blunt. Two varieties are described, in one of which the endosarc is occupied with multitudes of bright-yellow corpuscles; in the other, with green corpuscles. In most examples of the variety with green corpuscles, the body is covered with minute villi of protoplasm, which, though simulating the minute spicules investing Dinamceba, are clearly of a different character. HYALODISOUS. Gieeli, hualos, ciystal ; diseos, a qnoit. Byalodiseus : Hertwig and Lesser, 1874. FlaTcopua: Schulze, 1875. Body naked, discoidal, consisting of a colored granular endosarc, with nucleus and vacuoles, and a clear colorless ectosarc, which in motion of the animal extends in a broad zone beyond the colored mass of endosarcj and projects pointed conical processes mostly few in number. HYALODISCUS RUBICUNDUS. Plate XLV, flgs. 17,18. Hyalodiacus ruUoundus. Hertwig and Lesser : Arch. mik. Anat. 1874, x, Supl. 49, Taf. ii, Fig. 5. t Flahopus ruber. Schulze : Arch. mik. Anat. 1875, xi, 348, Taf. xix, Fig. 9-16. Endosarc brick-red in color. Sise. — 0.03-0.06 mm. diameter. In the outset of my studies of the Fresh-water Rhizopods, I met with several specimens of what I suppose to be the curious colored amceboid form described by Hertwig and Lesser under the name of Hyalodiscus rnbicnndus, but I have since seen no others. They were found in the ooze of Cooper's Creek, New Jersey, in the month of May. One of the specimens, shortly after being noticed, exhibited the appear- ance seen in fig. 17, pi. XLV. It had an irregularly circular outline, measured about 0.0625 mm. in breadth, and consisted of two portions. One of these was an orange or light brick-red body with a variable number of conical pointed processes ; the other was a thin, delicate, broad, cres- centic band of clear colorless ectosarc embracing more than half the cir- cumference of the former. The animal slowly glided in an amceba-like manner, in the direction of the pseudopodal expansion of ectosarc. In its GENUS HYALODISCUS— HYALODISCUS EUBICUNDUS. 95 movements the red mass underwent more or less change of shape, the sur- face at different points would rise and fall, and here and there the pointed processes would be withdrawn and others would be projected. The band of ectosarc also moved in a wave-like manner, extending and receding in different positions. The red mass of endosarc was composed of a basis of fine red granules with a few larger ones of the same color but darker, and a few scattered oil-like molecules. The central portion of the endosarc, from time to time, exhibited a clearer circular spot, apparently indicating the presence of a nucleus. There were also to be seen two or three small vacuoles, but I failed to detect any movement in them. Another specimen, found at the same time with the preceding, repre- sented in fig. 18, was about half the size. It was of the same color, but the endosarc contained a multitude of conspicuous globular colored corpus- cles mingled with the finer granular basis. The clear colorless ectosarc extended around the border of the colored endosarc, and projected a few conical processes, into which none of the colored granular matter of the latter rea^'lied. The movements of the animal were of the same character as in the former specimen. Plakopus ruber, described by Prof. Schulze, is probably identical with Hyalodiscus rubicundus, as suspected by this author, though it is a very much larger animal, and contains several nuclei. Prof. Schulze gives as the size of the former from 0.2 to 0.6 mm. DIFFLUGIA. Latin, diffluo, to flow. IKfflugia:Jjecleic,18l5. JrceZZa; Ehrenberg, 1841. XecgMereitma; Schlumberger, 1845. SomoeoOiUmys; ffeterocosmia; Mxasaula: Ehrenberg, 1871. Shell very variable in shape, usually composed of extraneous angular particles of hyaline quartz-sand, sometimes mingled with other bodies, such as diatom-cases, sponge-spicules, etc.; the same forms sometimes composed of chitinoid membrane incorporated with scattered extraneous particles or composed in part or entirely of intrinsic particles of peculiar character. Mouth inferior, usually terminal, rarely sub-terminal. Sarcodic mass com- monly occupying the greater part of the capacity of the shell, attached by threads of ectosarc to the interior of the fundus and sides, and by a pro- 96 FEESH-WATEE EHIZOPODS OF NOETH AMEEICA. longation to the margin of the mouth. Nucleus single, situated near tne fundus of the endosarc. Contractile vesicles several, situated at the periphery of the latter, contiguous to the nucleus. Pseudopods usually up to half a dozen or more, cylindrical, simple or branching, commonly rounded at the ends, sometimes spreading and pointed. DIFFLUGIA GLOBULOSA. Plates XV, figs. 25-31; XVI, figs. 1-24. Difflugia-glohulosa. Dujardin : An. Sc. Nat. 1837, viii, 311, pi. ix, figs. 1 a, 6; Hist. Nat. InfoBoires, 1841, 248, pi. ii, fig. 6. Pritchard : Hist. Infusoria, 1861, 554, pi. xxi, fig. 10. Difflmgia proteiformis. Ehrenberg: Infusionsthierclieu, 1838, 131, Taf. ix, Fig. i; MicrograpMc Diet. 1860, 232, pi. 23, fig. 39.— Pritchard: Infusoria, 1861, 553.— Leidy: Proc. Ac. Nat. Sc. 1877,307. Difflugia gloMlaris. WalUcli: An. Mag. Nat. Hist, xiii, 1864, 241, pli xvi, figs. 1, 2, 17, 27.— Iieidy: Proc. Ac. Nat. Sc. 1877, 307, 321. Difflugia protdformis, subspecies D. globularis. Wallich: Ibidem. Difflugia acropodia. Hertwig and Lesser: Arch. mik. Anat. 1874, x, Snpl. 107, Taf. ii. Fig. 6. Shell spheroidal or oval, with the oral pole more or less truncated. Mouth inferior, terminal, circular, usually truncating the shell; sometimes more or less protruding or bordered by a short neck, rarely more or less inverted. Shell commonly compdsed of quartz-sand, sometimes of diatoms, and sometimes of chitinoid membrane usually incorporated with more or less sand and, diatoms. Sarcode, independent of the food, colorless. Size: — Smallest specimen, with shell of sand, 0.036 mm. long by 0.03 mm. broad; with the mouth 015 mm, wide. Chitinoid specimens, with diatoms and sand, from 0.024 mm. long by 0.032 mm. broad; with the mouth 0.016 mm. wide, to 0.108 mm. long, 0.12 mm. broad; with the mouth 0.06 mm. wide. Largest specimens, of sand grains, 0.26 mm. long, 0.184 mm. broad, with the mouth 0.08 mm. wide. Localities. — In the ooze of ditches and ponds frequent, in the vicinity of Philadelphia, Pennsylvania, New Jersey, Maine, Rhode Island, Connec- ticut, Florida, Alabama, Nova Scotia, Utah, and near Fort Bridger and in the Uinta Mountains, Wyoming Territory. Small foi*ms are not unfre- quent on moist earth in bogs, meadows, and even, with algae and mosses, in the crevices of the brick pavements of the city of Philadelphia. Dujardin, in 1837, described a species with the name of Difflu§^ia g'lobnlosa, in wbich he says the shell is corneous, globular, and 0.1 mm. long. Of the accompanying figures, one is ovoid, with the mouth at the nan-ower end ; the other is represented as an upper view, and is oval, so GENUS DIFFLUGIA— DIFFLFGIA GLOBULOSA. 97 that, if strictly correct, the shell would be compressed ovoid. Later, he describes the shell as brown, globular, or ovoid and smooth; and the accompanying figure is circular in outline, with pseudopods directed from one pole. Ehrenberg, in 1838, described an oval form, the shell of which is composed of quartz-sand, as Difflugia proteiformis, and attributes this name to Lamarck. To the same he refers one of the three difi'erent forms described by Leclerc as characteristic of the genus Difflugia. Lamarck, however, applied the name of D. proteiformis to all the forms indicated by Leclerc, without discrimination. Of the three difi'erent forms noticed by Leclerc, one is readily recog- nizable as Difflugia spiralis; a second, as D. acuminata; while the third, referred to D. proteiformis by Ehrenberg, from its shape would appear rather to associate itself with the D. pyriformis oi Dr. Perty. Dr. Wallich describes a more or less globular form, the shell of which is composed of quartz-sand, or this together with diatoms, as a subspecies of D. proteiformis, with the name of D. glohularis. This name he attributes to Dujardin, evidently in mistake for that of D. globulosa. Difflugia globulosa, as I have supposed it to be, is not uncommon in the ooze of ponds and ditches, and the smallest examples are frequent among moss, algJE, and other plants in damp shaded places. The shell varies in shape from oval to ovoid and subpyriform, and to spheroidal and oblate spheroidal, as seen in figs. 25-31, pi. XV, and figs. 1-24, pi. XVI. The oral pole of the shell is more or less truncated, and the mouth is large, circular, entire, inferior, and commonly terminal. Mostly it forms the truncation of the oral pole, but sometimes the latter is more or less inflected, and the mouth becomes elevated above the level of the bottom of the shell. Less frequently, the mouth is more or less pro- jected, so as to produce a short neck to the shell. Oval or ovoid varieties of the shell merge into forms which may be regarded as pertaining to Difflugia piriformis. Oblate spheroidal shells, with the oral pole more or less inflected to the mouth, resemble in shape the shell of a sea-urchin. Echinus. In structure, the shell, as usual in other species of Difflugia, is com- posed of particles of quartz-sand, as represented in most of the figures above indicated. The smallest specimens frequently consist of chitinoid 7 RHIZ 98 FRESH- WATER RHIZOPODS OP NORTH AMERICA. membrane incorporated with Variable proportions of sand grains, as seen in figs 13-17, pi. XVI. Specimens, found in sphagnous swamps, sometimes consist of chitinoid membrane incorporated with variable .pro- portions of diatoms, or fragments of the same, with sand grains and other particles of a less determinate character, as represented in 'figs. 9, 10, 18, 19, pi. XVI. Specimens are also fomid, in the same situations, composed almost entirely of diatoms, as represented in figs. 2 1 , 22. The larger shells of Difflugia gldbulosa, composed of quartz-sand, are commonly colorless, but may be more or less yellowish or brownish, apparently due to ferrugi- nous staining. Occasionally specimens are seen, like those of figs. 23, 24, in which the cementing material of the sand particles exhibits a deeper stain of the same kind. The smallest shells are more commonly of a yellowish hue. In my experience it has occurred to meet with dead shells of D. gldbulosa more frequently than with living specimens. The sarcode of D. gldbulosa, independent of food contents, is colorless. Difflugia gldbulosa through intermediate forms merges into D. pyriformis, and I suspect also into 2). Idbostoma. The small oblate-spheroidal forms, with inflected base, especially when mainly composed of chitinoid mem- brane, are scarcely distinguishable from Arcellas. I have also seen speci- mens in which the mouth was more or less eccentric, and I was uncertain whether to refer them to the species under consideration, or whether to regard them as pertaining to Difflugia constricta, or the spineless form of Centropyxis aculeata. The range of size is considerable. The smallest specimens, found among moist earth, measured about 0.036 mm. long by 0.03 mm. broad, with the mouth 0.015 mm. The largest specimens, from the ooze of a pond, measured 0.3 mm. in diameter, with the mouth 0.16 mm. DIFFLUGIA PYRIFORMIS. Plates X; XI; XII, figs. 1-18; XV, figs. 32,33; XVI, fig. 38; XIX, figs. 24-26. Difflugia. Leolero : Mdm. Mus. Hist. Nat. 1815, ii, 474, pi. 17, fig. Diffl/iigia pyriformis. Perty : Mittheil. Natnrf. Gesells. Bern, 1848, 168 ; Kennt. Tdeinst. Lebensformen, 1852, 187, Tab. ix. Fig. 9.— Pritohard : Hist. Infusoria, 1861, pi. xxi, fig. 17.— Carter : An. Mag. Nat. Hist, xii, 1863, 249; xiii, 1864, 21, pi. i, fig. 1.— Wallich: An. Mag. Nat. Hist. xiii, 1864, 240, pi. xvi, figs. 9, 10, 39, 40.— Ehrenberg : Ab. Ak. Wis. Berlin, 1871, 264.— Leidy : Pr. Ac. Nat. Sc. 1874, 14, 79 ; 1877, 307. Difflugia proteiformis. In part of Lamarck and Ehrenberg = Loclerc's figs. 2, 3, pi. 17, M6m. dii Mus. d'Hist. Nat. ii, 1815. GENUS DIFPLUGIA— DIFFLUGIA PTEIFOEMIS. 99 Difflugia ? Carter: Ab. Mag Nat. Hist, siii, 1864, 29, pi. i, fig. 11. Difflugia proteiformis, suljsp. D. mitriformis, var. Z>. pyriformia. Wallicli: An. Mag. Nat. Hist, xiii, 1864, 240. JDifflugia compressa. Carter : An. Mag. Nat. Hist, xiii, 1864, 22, pi. i, figs. 5, 6. — Leidy : Proc. Ac. Nat. So. 1874,14; 1875,307. D. Corticellaptjriformis. Ehrenljerg: Abh. Ak. Wis. Berlin, 1871,247. Difflugia entoohloris. Leidy : Pioc. Ac. Nat. ,Sc. 1874, 79; 1875, 307. Difflugia vas. Leidy : Pr. Ac. Nat. So. 1874, 155; 1875, 307. Difflugia nodosa, vai. of pyriformia. Leidy : see following pages. Difflugia cornuta, var. of pyriformia. Ibidem. Shell pyriform, flask-shaped, or ovoid, with the narrower pole prolonged into a neck of variable length, of uniform transverse diameters, or more or less compressed ; fundus obtusely rounded or subacute, or more or less ex- panded and variably produced into from one to three conical processes; neck gradually and evenly narrowed to the oral end, cylindroid, sometimes con- stricted ; mouth inferior, terminal, circular, or slightly oval. Structure of the shell usually of angular particles of quartz-sand, sometimes mingled with diatoms ; less frequently composed of chitinoid membrane, with vari- able proportions of diatoms and sand. Sarcode mostly with the endo- sarc bright green, from the presence of chlorophyl grains, but often color- less, except as modified by the presence of food. Size. — Ranging from 0.06 to 0.58 mm. long, 0.04 to 0.24 mm. broad; mouth 0.016 to 0.12 mm. wide. Locality. — ^Everywhere in the ooze of ponds, ditches, and bogs. Observed in Pennsylvania, New Jersey, Rhode Island, Connecticut, Florida, Alabama, Nova Scotia, Colorado, Utah, Fort Bridger, and Uinta Mountains, Wyoming. Variety I. — B. pyriformis ; the ordinary characteristic form, with the opposite diameters uniform. See pi. X. Variety 2. — D. comj^ressa ; like the preceding, but more or less com- pressed. See pi. XI, figs. 1-6 ; pi. XII, figs. 10-16. Variety 3. — D. nodosa ; usually a large form like the latter, but with the fundus variably produced into from one to three eminences. See pi. XI, figs. 7-22. Variety 4. — D. cornuta ; pyriform, with the fundus provided with one or two pointed conical processes. See pi. XII, figs. 17, 18. Variety 5. — B.vas; like the ordinary form, but witli the neck defined from the body by a constriction. See pi. XII, figs. 2-9. 100 FRESH-WATEE EHIZOPODS OF NOKTH AMERICA. Difflugia pyriformis is one of the most common species, and it presents much variety of shape and size. The shell is ordinarily flask-like or baloon-form, or, as indicated by the specific name, pear-shaped, with an oval or ovoid body more or less gradually prolonged into a neck, which tapers to the mouth or is cylindroid, and of variable proportionate length. Usually the shell is of uniform diameters, but is sometimes more or less compressed so as to be wider in one direction. Occasionally specimens occur exhibiting some want of bilateral symmetry. The fundus of the shell is mostly regularly rounded, but sometimes is more or less subacute. The mouth is inferior, terminal, and circular or oval. Characteristic specimens of the ordinary forms, exhibiting considerable variety in exact shape, size, and structure, are represented in pi. X. Specimens of JDifflugia pyriformis of the ordinary kinds have a wide range in size. Some of the smallest measure only the ith of an inch, ■ while large ones reach ten times that length. Compressed forms oi D. pyriformis, constituting what I have viewed as the variety — and agreeing with Mr. Carter's species — D. compressa, are unfrequent compared with those with more uniform diameters. Intei'me- diate conditions occur, showing the gradation of one form into the other. In D. compressa, the shell exhibits variable degrees of compression, some- times comparatively little, at others to such an extent that the shell is twice the breadth in one direction that it is in the other. The length usually exceeds the greater breadth, but rarely the latter actually exceeds the former. Specimens exhibiting various degrees of relative breadth are represented in figs. 10-16, pi. XII. The size of compressed specimens I have found to range as follows : Length ji th to ^th of an inch ; greater breadth ^th to ^^th of an inch ; lesser breadth ith to jigth of an inch ; with the oral end giotli to jjgth of an inch in the greater width. A striking variety of B. pyriformis, certainly not distinct from this as a species, I have named D. nodosa. It is not an unfrequent associate with the more ordinary form, and is distinguished by its usually large size, its more or less compressed form, and its broad fundus, which is produced into from one to three knobs or conical eminences, varying greatly in degree of development. GENUS DIFFLUGIA— DUTLUGIA PYEIFOEMIS. 101 In the summer of 1874, I found this variety in extraordinary profusion in Swarthmore brick-pond, and all the specimens of pi. XI were derived from this locality. The subsequent two seasons I could find none of the kind in the same pond, but in 1877 it again appeared in moderate quantity. When first discovered, the specimens were so abxmdant that a drop of ooze, in which the animal lived, would often contain several dozen indi- viduals. They were remarkable for their large size, and the brig) it green color and activity of the animal. Notwithstanding the great number of indi- viduals, scarcely two could be found in all respects alike. The general shape was that of the ordinary D pyriformis, usually more or less com- pressed ; but the proportions varied considerably. Commonly the breadth was nearly or quite double in one direction what it was in the other ; but sometimes the compression was trifling, when the shell presented the ordinary form of B. pyriformis. Commonly the greatest breadth occupied the upper third or fourth of the shell. In the view of the specimens from the narrower side, the shape was pretty uni^rmly pyriform. In the view from the broader side, the lateral border varied from an inclined plane to a concave line, while the fundus varied exceedingly ; sometimes from evenly convex to obtusely angular ; sometimes from horizontally straight to concave ; sometimes with a single median eminence, a pair of lateral eminences, or a transverse row of three, and all variable in their proportions. Unsymmetrical forms also occurred, in which the knobs or eminences on one side of the shell were dispropor- tionately produced. The size of the knobby specimens, from Swarthmore pond, ranged as follows : the smallest specimen was ^d of an inch long ; ith of an inch in the greater, and ji^th of an inch in the lesser breadth. A large specimen measured ^th of an inch long ; ^th of an inch in the greater, and ^th of an inch in the 'lesser breadth, with the oral end jith of an inch wide. In my early observations on the variety D. nodosa, T was led to view it as a species distinct from Z>. pyriformis, and from the bright green color of the endosarc I named it D. entochloris. Another variety of Bifflugia pyriformis, which I formerly supposed to be a distinct species, I named B. vas. It has the shape of the more charac- teristic sjoecimens of B pyriformis, but has the neck defined from the body 102 FEESH-WATBE EHIZOPODS OF NOETH AMEEICA. by a narrow constriction, as seen in figs. 2-9, pi. XII. I think there can be but little doubt that this variety and the ordinary more familiar form of B. pyHformis merge into one another ; and I have met with various inter- mediate forms. See figs. 24-26, pi. XIX. The specimens vary greatly in size, and this is also the case in the proportions of the body and neck of the shell. Ordinarily those from Absecom pond range from |;th to ith of an inch in length. The smallest specimen observed, from Swarthmore brick-pond, was ith of an inch long and g-^yth of an inch broad. The largest one, from Absecom pond, was ith of an inch long by ^th of an inch broad. Still another variety which I have occasionally seen is represented in figs. 17, 18, pi. XII. It may be distinguished as D. cornuta, and has the characteristic form of D. pyriformis, but has the fundus provided with one or two conical spines. This variety I have observed to approximate by intermediate forms the more characteristic ones of J), acuminata. The shell of Difflugia pyriformis is commonly composed of coarse, irregular grains of hyaline quartz-sand, and is often the roughest of its kind; though sometimes, considering the coarseness of the materials, the shell is wonderful for its evenness. The shell may be composed altogether of comparatively lai'ge stones, or it may be partly constructed of these more or less uniformly distributed, with the intervals filled in with smaller ones. Sometimes the larger stones especially occupy the fundus or the greater part of the body, and the neck is composed of smaller ones; some- times the arrangement is reversed, and sometimes the largest stones are arranged contiguous to the mouth. Not unfrequently one or several stones greatly exceed the others, and produce conspicuous unsymmetrical projec- tions in the shell, as seen in figs. 6-9, 12-15, pi. X; figs. 37, 38, pi. XVI. It may not be unworthy of remark, that the coarsest and most uneven specimens are found together in association with the smoothest, in the same localities and apparently under the same circumstances. Less frequently the shell of Difflugia pyriformis is constructed of an intermixture of quartz-sand and diatoms in varying proportions, usually the former predominating, but sometimes the latter. Large naviculas are often conspicuous among the building materials, and occasionally spicules ©f the fresh-water sponge are noticed with them. Such specimens are represented in figs, 13, 15, 18-21, pi. X. Sometimes the shell of D. pyri- GENUS DIFPLUGIA— DIFFLUGIA PYEIFOEMIS. 103 formis consists of chitinoid membrane, colorless or straw-colored, and having incorporated variable quantities of diatoms and sand, as seen in figs. 22-26, pi. X. Specimens of this kind, of the smallest size, occasionally- met with, are remarkable for the great proportionate size of the adherent diatoms, as seen in figs. 22, 23, reminding one of the cases of the basket- worm {Thyridopteryx), often seen suspended from the branches of the arbor- vitse and other trees. Earely I have seen a Difflugia, referable to D. pyriformis, in which the shell appeared to be composed of chitinoid membrane incorporated with flocculent black matter, apparently from the sediment of the locality in which the creature was found. Such a specimen is represented in fig. 27, pi. X. The shell of D. pyriformis, in all the specimens included as varieties under the names of D. compressa, B. nodosa, D. vas, and D. cornuta, as seen in tHe various figures of these, in plates XI and XII, was composed exclu- sively of angular particles of quartz-sand. Rare, indeed, is it to see a rounded particle of quartz-sand entering into the construction of the shell of any Difflugia ; but an example of one such shell, pertaining to D. pyri- formis, exhibiting several rounded sand grains, is seen in fig. 15, pi. X. The interior sarcode of Difflugia pyriformis, as usual in the genus from the nature of the shell, is greatly obscured from view. Commonly, the greater portion of the mass occupying the body of the shell is of a bright green color due to the presence of an abundance of chlorophyl granules, which appear to be an intrinsic element of structure of the endosarc. Less frequently the sarcode appears to be in greater part or even entirely colorless, except that the central portion may be more or less colored by the presence of food contents. The expressed sarcode of D. pyriformis usually exhibits a faintly granular and colorless basis mingled with variable proportions of bright green chlorophyl granules, and others which are colorless and darkly defined and resemble starch. Besides these, there may be seen a large and clear or faintly granular nucleus, together with the varied constituents of the food. In individuals with uncolored sarcode, the chlorophyl granules are absent, and such also appears to be the case with most of the starch-like granules. Sometimes, in the bright green specimens, the expressed nucleus exhibits a uniform and distinct granular appearance. Mr. Carter, in an account 104 FEESH-WATER EHIZOPODS OF NORTH AMERICA. of the structure of the sarcode of Difflugia pyriformis, indicates two dif- ferent conditions or stages as above described. The chlorophyl granules, when present, he regards as part of the structure of the animal, as much so as the same colored element is, in the green fresh-water polyp (Hydra viridis). Colorless granules, in association with the green ones, he deter- mined to be of the nature of starch, and these he also regards as part of the structure of the animal. In the colorless stage of the latter lie further intimates the absence of the chlorophyl and a diminution in the quantity of the starch.* According to the same able investigator, the green condition of the sarcode is associated with greater activity of the animal, and is especially common in the spring season; while the colorless condition, indicative of more passive habit, occurs in autumn. The changes in color he supposes to be connected with changes in the nucleus, and to be related with the reproductive process. * The Swarthmore specimens, above mentioned, found in such profusion in the summer of 1874, were all possessed of a bright green endosarc, and were in the most active condition. Neither before nor since have I met with any form of Difflugia which exhibited more lively movements, and such varied changes in the appearance of the pseudopods. Extreme extension of the latter was accompanied by an influx of more or less of the endosarc with chlorophyl and starch-Hke granules. Of the many changes presented by the pseudopods, examples are given in the figures of pi. XI. While it has occuiTed to me to see multitudes of Difflugia pyriformis in all its varieties of the ordinary form, and of D. compressa, D. nodosa, and D. vas, with the sarcode in a bright green condition, at all temperate seasons of the year, I have also observed them in the Qolorless condition in variable, but comparatively small, proportion, at the same times and in the same localities. The animal is also to be seen of every grade, from that in which the body of the shell appears in greater part to be occupied by a bright green endosarc, to that in which all color is absent except what is due to the presence of food. Commonly, when the bright green specimens of JD. pyriformis are abundant, the uncolored ones are comparatively few. I have further observed bright green specimens of B. pyriformis, in which the sar- code was not only in a passive condition, but was contracted into a central • Anuals aud Magazine of Natural History, xii, 1863, 249. GENUS DIFPLUGIA— DIPFLUGIA PYEIFOEMIS. 105 ball occupying the body of the shell. Not unfrequently specimens appear as if the color of the sarcode, as it is ordinarily seen, had undergone a change into a yellowish or brownish hue. Difflugia piriformis was first described with this name by Perty,* from specimens collected in Switzerland. Two of the figures accompanying Leclerc's original description of the characters of the genus Difflugia appear to belong to the same.f These figures EhrenbergJ refers to his ow^n B. proteiformis, attributing the name to Lamarck, § who, however, applied it without discrimination to all the forms, comprising three distinct ones, de- scribed by Leclerc as representing the genus. Ehrenberg's figures and description of B. proteiformis,\\ as I have before intimated, appear rather to apply to the B. globulosa of Dujardin.TE Ehrenberg remarks of B. dblonga, described and figured in the 'Infusionsthierchen' as a form with a purely chitinoid shell, that if it is the same as the B. pyriformis, of Perty, deprived of its incrusting material, as intimated by Claparfede and Lach- mann, the latter name should be disused.** This would be just, if we could be positive of the relation of B. dblonga with B. pyriformis; but in its shape it appears rather to be related with B. acuminata without its point. Carterff and Wallichf t describe Bifflugia pyriformis as occurring both in England and India. The latter author refers the more ordinary form, as a variety, to a subspecies which he names D. mitriformis. Figures of the latter, with one or two points to the fundus, he refers to B. acuminata as another variety of B. mitriformis.§§ Lang describes a form under the name of B. triangulata, the figures of which remind me of the knobby variety of B. pyriformis. The shell is described as triangular, flat, membranous, and reticulated. |||| Bifflugia pyriformis by gradual transition merges into B. globulosa, B. acuminata, etc. * Keunt. kleinst. Lebensformen, 187. + M6m. Mus. Hist. Nat. ii, 1815, pi. 17, figs. 2, 3. X Infusionsthierchen, 131. § Animaux sans Vertfebres. II Infusionsthierchen, Taf. ix, Fig. i. HAn. So. Nat. 1837, viii, 311, pi. ix, fig. 1; Hist. Nat. Infusoires, 248, pi. ii, fig. .6. **Abh. Ak. Wis. Berlin, 1871,256. ttAn. Mag. Nat. Hist, xu, 1863, 249. Xt Ibid, xiii, 1364, 240. §$ Ibid. pi. xvi, figs. 7, 8, 12 5. III! Quart. Jour. Mio. So. t, 1865, 285. 106 FEESH-WATBE BHIZOPODS OF NORTH AMERICA. DIFFLUGIA URCEOLATA. Pl-^tes XIV; XVI, figs. 32-34; XIX, figs. 28, 29. Difflvgia urceolata. Carter : An. Mag. Nat. Hist, xiii, 1864, 27, 37, pi. i, fig. 7.— Leidy : Pr. Ac. Nat. So. 1877, 307. IMfflugia lageniformis. Wallich : An. Mag. Nat. Hist, xiii, 1864, 240, pi. xvi, figs. 15, IC. — Leidy : Pr. Ac. Nat. Sc. 1874, 14. Difflugia proteiformis, subspecies B. mitriformis, var. D. lageni/ormia. Wallich : Ibid. Bifflugia amphora. Leidy: Proc. Ac. Nat. Sc. 1874,79. Biffliigia olla. Leidy : Proc. Ac. Nat. Sc. 1874, 156 ; 1877, 307. Shell amphora-form ; body spheroid, ovoid, or ovate, with the fundus obtusely and evenly rounded, or more or less acute, or acuminate, and rarely furnished with several usually blunt spines ; neck short, more or less contracted ; mouth large, circular, terminal, with or without a rim of varia- ble breadth, usually reflected and terminating in a thin delicate edge. Struc- ture of the shell commonly of hyaline quartz-sand ; rarely of chitinoid membrane with variable proportions of diatoms and sand. Sarcode color- less ; pseudopods many, digitate, simple, and branching. Sise. — Of the spheroid forms, from 0.18 mm. to 0.44 mm. long by 14 mm. to 0.38 mm. broad ; of the ovoid forms, 0.2 mm. to 0.52 mm. long by 0.14 mm. to 0.36 mm. broad. Locality. — Ditches and ponds in the vicinity of Philadelphia ; ponds of sphagnous swamps in New Jersey ; pools and ponds at Fort Bridger, on Bridger Butte, and in the Uinta Mountains, to an elevation of 10,000 feet, Wyoming Territory. Difflu§ria urceolata was originally described by Mr. Carter from specimens found in England. It is represented as of oval fonu, shghtly prolonged to form a short neck, and with a rim slightly reflected. Its size is stated at ^d of an inch in length and id of an inch in breadth. The species was described the same year by Dr. Wallich, likewise from specimens found in England, under the name of Difflugia lageniformis. It is represented of oval form, with a short contracted neck and a strongly reflected lip. Difflugia urceolata is the largest species of the genus, and is common in the ooze of ditches traversing the meadows below the city of Philadelphia, and communicating with the Delaware and Schuylkill Rivers. It is also frequent in the ponds of sphagnous swamps, such as those of Atco, and GEEUS DIFFLUGIA— DIFFLUGIA UECEOLATA. 107 Absecom, and Lake Hatacawanna, New Jersey; and I also found it abun- dantly in ponds of the Uinta Mountains, Wyoming Territory. Ordinarily the shell of Difflugia urceolata strikingly resembles the ancient Roman amphora. The body of the shell varies from a globular shape to a more or less ovoid form. The upper extremity, or fundus, is obtusely rounded or more or less acute, and sometimes it is rounded and more or less acuminate. The neck is a short and slight cylindrical constriction from the body. The mouth is large and circular, and frequently truncates the neck ; but, mostly, it is surrounded by a lip of variable breadth, usually more or less reflected, and terminated by a thin delicate edge. Sometimes the neck is more or less everted, and terminates at the mouth without extending in a circular lip or rim. PL XIV, figs. 1-8 ; pi. XVI, figs. 33, 34. The size of the spheroidal forms of B. urceolata ranges from about the jijth to the ^„th of an inch in diameter ; the ovoid forms measure from the ith to the ith of an inch in length. In the ponds of sphagnous swamps of New Jersey, a variety of JD. urceolata is common, in association with the more ordinary forms, in which the fundus of the shell is provided with usually from three to half a dozen nipple-shaped spines. This constitutes the variety I formerly named D. olla. The shell is commonly of the shape of the spheroidal form of J). urceolata. The spines are mostly blunt, and often terminate in a single stone flake of greater width than the spine at its point of attachment. They are arranged in a circle, more or less regular, around the fundus, usually unaccompanied by a central spine, though occasionally also there is one in this position. They are mostly shorter, less acute, and less eccen- tric than the conical spines in a similar position in D corona. Examples of the variety named JD. olla are represented in figs. 10-13, pi. XIV; fig. 32, pi. XVI ; and figs. 28, 29, pi. XIX. The shell of Difflugia urceolata is composed, as is generally the case in other species of the genus, of colorless angular particles of quartz-sand, mostly of larger ones scattered with some appearance of regularity, while the intervals are occupied with smaller ones. The surface of the shell, though often uneven, is less so commonly than in some of the smaller species of Difflugia. Frequently larger stones occupy the neck of the shell, 108 FEESH-WATEE EHIZOPODS OP NOETH AMEEICA. but passing thence they gradually become smaller approaching the edge of the rim or reflected lip. Only in the variety with spines to the fundus, previously indicated as D. olla, from the sphagnous ponds of New Jersey, have I seen a few speci- mens in which the shell was composed of colorless chitinoid membrane, incorporated with diatoms and fine sand grains, as seen in fig. 29, pi, XIX. The interior sarcode of D. urceolata, in all its variety of forms and in all seasons, I have found to be colorless, independently of the hues given to the central portion of the endosarc by the varied nature of the food. The pseudopods are ordinarily from two or three to half a dozen, and of the usual simple digitate kind. Difflugia urceolata by transitional forms merges into D. acuminata. DIFFLUGIA CRATERA. Plates XII, figs. 19-21 ; XVI, fig. 35. Difflugia cratera. Leidy : Proc. Ac. Nat. Sc. 1677, 307. Shell goblet-shape, with oval or spheroidal body and wide cylindroid neck; fundus obtuse; mouth terminal, large, circular, truncating the neck, or with a reflected rim. Composed of colorless chitinoid membrane, incor- porated with minute particles of sand and dirt. Size. — Length 0.056 mm. to 0.066 mm.; breadth of body 0.036 mm. to 0.042 mm.; breadth of neck 0.028 mm. to* 0.036 mm. Locality. — Among Ceratophyllum and other aquatic plants. Canal at Bristol, Berks County, Pennsylvania; Buffalo, New York. Difflug^ia cratera is one of the smallest species of the genus, and, though apparently rare, may be common enough, but ha,ve escaped frequent observation from its diminutive size. I first found it among hornwort, col- lected in the canal at Bristol, Pa., August, 1876, and noticed about a dozen individuals. I have since met with it recently, August, 1878, in some sediment from the water-supply of Buffalo, New York. The sediment sent to me, on a glass slip, for examination, consisted mainly of the curious four-spined infusorian, Ceratium longicorne, and with it I detected two individuals of Difflugia cratera. All the specimens observed appeared to be empty shells, though it is not improbable some of them may have contained the living sarcode, which, being contracted and transparent, escaped notice. GENUS DIFFLUGIA— DIFFLUGIA CEATEKA. 109 Later, October, 1878, in an additional supply of sediment, received from Buffalo, in association with Geratium hngic'orne, I observed a number of specimens of the same little Difflugia. The Bristol specimens of Difflugia cratera varied but slightly in any respect. The shell, as represented in figs. 19, 20, pi. XII, was goblet- shaped, with the body and neck of nearly equal length. The body, a little longer than the neck, was ovoid, with the narrower pole forming the fundus of the sheU. The neck was wide, cylindroid, and slightly ex- panded approaching the mouth, which was large, circular, and terminal. The Buffalo specimens differed considerably from the former, as well as among themselves, as seen in fig. 21, pi. XII, and fig. 35, pi. XVI. The beautiful goblet-shaped shells varied in the proportionate length of the body and neck. The former was more or less oblately spheroidal, and the latter longer or shorter than the body, and expanded in variable degrees approaching the mouth. In all the specimens, from both localities, the shell was composed of colorless chitinoid membrane, which exhibited a minutely wrinkled appear- ance, and sparsely scattered over the surface there were a few minute sand grains and fine particles of dirt. The Bristol specimens measured about 0.056 mm. in length ; the Buf- falo specimens ranged from 0.066 mm to 0.072 mm. in length. Since the above was written, it has occurred to me that the minute shells, referred to Difflugia cratera, may perhaps pertain to a species of ciliated infusorian, of the genus Tintinnus. DIFFLUGIA ACUMINATA. Plate XIII. Difflugia. Leclerc: M^m. Mus. Hist. Nat. ii, 1815, 474, pi. 17, fig. 5. Difflugia acuminata. Ehrenberg : Infusionsthierchen, 1838, 131, Taf. ix. Fig. iii. — ^Perty : Kennt. kleinst. Lebensformen, 1852, 187.— Leidy : Pr. Ac. Nat. Sc. 1874, 14, 79 ; 1877, 307. Difflugia acuminata, var. acaulis. Perty : Ante, 187, Taf. ix, Fig. 6. Difflugia bacillariarum. Perty : Ante, 187, Taf. ix. Fig. 7. Difflugia pj/riformis. Carter: An. Mag. Nat. Hist, xii, 1863,251; xiii, 1864, 36, "acuminated variety," pi. i, fig. 1 1. Difflugia proteiformis, var. acuminata. Wallich : An. Mag. Nat. Hist, xl, 1863, 453, pi. x, fig. 13. Difflugia f Carter : An. Mag. Nat. Hist, xii, 1864, 29, pi. i, fig. 10. Difflugia proteiformis, subspecies D. mitriformis, var. D. acuminata. Wallich: An. Mag. Nat. Hist, xiii, 1864, 240, pi. xvi, figs. 11, 12. D. Corticella acuminata. Ehrenberg : Abh. Ak. Wis. Berlin, 1871, 247. Shell amphgra-form or oblong oval, pyriform, or cylindroid with the upper part more or less inflated ; fundus acute, acuminate, or prolonged no FEESH-WATEE EHIZOPODS OF ]SrOETH AMEEICA. into a nipple-shaped process, rarely with two or three points ; neck long, short, or none; mouth large, terminal, circular; lip usually straight. Com- posed of angular qiiartz-sand, sometimes with intermingled diatoms, rarely of the latter altogether, sometimes of chitinoid membrane with scattered sand and diatoms. Sarcode colorless ; pseudopods as usual in the genus. Sise. — Smallest specimens with shell of sand were 0.1 mm. long, 0.048 mm. broad, and 0.032 mm. wide at the mouth; large pyriform specimens of sand, 0.4 mm. long, 0.184 mm. broad, and 0.064 wide at the mouth; largest cylindroid ones of stones, 0.520 mm. long, 0.12 mm. broad, and 0.1 mm. wide at the mouth. Smallest specimens with the shell of diatoms measured about 0.084 mm. long, 0.036 mm. broad, and 0.024 mm. at the mouth. Locality, — ^Ditches near Philadelphia, Swarthmore pond. Darby pond, Pennsylvania ; Absecom pond, and ponds of Atco, Kirkwood, and other sphagnous swamps of New Jersey; ponds at Fort Bridger and Uinta Mountains, Wyoming Territory. France, Leclerc; Berlin, Ehrenberg; Switzerland, Perty ; England, Carter and Wallich. The shell of Difliu§^ia acuminata in shape is like an ancient Roman amphora, or is oblong oval, gradually narrowing toward the oral extrem- ity, and acute or tapering at the summit ; or it is pyriform, with the fundus in the latter condition ; or it is cylindroid, more or less inflated above, and tapering at the fundus. See pi. XIII. The mouth is terminal, circular, and large, with the lip straight or slightly contracted and rarely slightly everted. In one instance only, as seen in fig. 12, have I seen it surrounded by a projecting rim. The shell either narrows from the body gradually and regularly to the mouth, or more or less abruptly, forming a neck of variable length, sometimes short, sometimes long, and of every interme- diate degree. The longer-necked varieties present us with the pyriform and drop-tube-like shells. The fundus of the shell presents various degrees of acuteness, passing into a more or less acuminate condition or prolonged into a nipple-like pro- cess, which may be short and thick, or long and narrow. The process is usually straight, but is often bent to one side, and sometimes occupies a position unsymmetrically to one side. Rarely there are two or three processes to the fundus, as seen in figs. 25-29, pi. XII. The amphora-like specimens of Difflugia acuminata graduate into D. GEKUS DIFFLUGIA— DIFFLUGIA ACUMINATA. HI urceolata, and the pyriform varieties into JD. pyriformis, while the drop- tube-hke forms are the most pecuHar or characteristic. The shell of Difflugia acuminata is ordinarily composed of clear quartz- sand, as in D. pyriformis. Occasionally I have seen particles of garnet mingled with the former, as represented in figs. 14, 15, pi. XIII. Some- times the quartz-sand is mingled with variable proportions of diatoms. Not unfrequently the shell is composed of colorless chitinoid membrane, incorporated with quartz-sand alone or with this and intermingled diatoms. In this kind usually the grains of sand are closely placed in juxtaposition at and near the mouth of the shell, but are elsewhere scattered and separated by wide intervals. In some cases, the shell is more or less covered with large diatoms, generally adherent in the length, and diverging upward beyond the boundary of the shell, as seen in figs. 21, 22. Certain specimens found among sphagnum consisted entirely of dia- toms, as seen in figs 23-26, in most cases (which is unusual) still retaining portions of the endochroine. The sarcode of Difflugia acummata is colorless, excepting the usual coloring in the endosarc dependent on the presence of food, though I have met with an individual, as seen in fig. 15, in which the endosarc was bright green. In this case the color may have been due to the food, as the specimen was obtained from among an abundance of green alga. It should be mentioned, however, in this relation, that most of the specimens from which drawings were made were empty shells, chosen on account of their comparative translucency and distinctness of structure. The range of size of Difflugia acuminata is considerable. The smallest ones observed are those composed of diatoms, from sphagnum. These are about the ith of an inch in length by the ^th of an inch in breadth One of the smallest amphora-like shells, composed of sand, measured the jjjth of an inch long by the ~^i\x of an inch broad. One of the largest anaphora-like shells, composed of sand, measured the ^th of an inch long by the jj-^th of an inch broad ; and one of the largest pyriform shells had nearly the same measurement. 'J'he largest drop-tube-like shell measured nearly the ith of an inch long by the —^ of an inch in breadth. Difflugia acuminata is one of the commonest of the genus, and is found almost everywhere with other familiar kinds of Difflugia. It is one of the three forms originally indicated and figured by Leclerc as character- 112 FRESH- WATEE RHIZOPODS OP NORTH AMERICA. istic of the genus. It was described and figured by Ehrenberg in the 'Infusionsthierchen,' and was first specifically named by him. It was also figured and described under the same name by Perty, and subsequently likewise by Carter and Wallich. Perty represents a specimen in which the shell appears to be composed of chitinoid membrane incorporated with scattered quartz grains. He also figures and describes another under the name of Bifflugia hacillariarum, which appears to be a variety of Z>. acuminata in which the shell is com- posed of diatoms. DIFFLUGIA LOBOSTOMA. Plate XV, flgs. 1-24; XVI, figs. 25-29. Viffiugia protdformis. Carter: An. Mag. Nat. Hist, xviii, 1856, 128. Difflugia trieuspia. Carter: An. Mag. Nat. Hist, xviii, 1856, 221, pi. vii, flg. 80. — Ehrenberg: Ab. Ak. Wis. Berlin, 1871, 264. Difflugia oblonga. Fresenius: Abb. Sencienb. Naturf. Gesells. ii, 1856-8, 225, Taf. xii. Fig. 43-45. D. Exassvla tricuKpis. Ehrenberg : Abh. Ak. Wissens. Berlin, 1871, 246. Difflugia lobostoma. Leidy : Pr. Ac. Nat. So. Phil. 1874, 79 ; 1877, 307. '^ Difflugia crenulata. Leidy: Pr. Ac. Nat. Sc. Phil. 1874, 79. Shell ovoid, oval, or nearly spherical, usually composed of quartz- sand, rarely in part or wholly of diatoms or of chitinoid membrane with a few quartz particles; mouth terminal, usually from three- to six-lobed, occasionally more; fundus obtusely rounded. Sarcode colorless, or with the endosarc colored green from the presence of abundance of chlorophyl granules; pseudopods to half a dozen or more, and exhibiting the usual shape and changes as in other species. Sige. — Ordinarily about 0.12 mm. long and 0.1 mm. broad, with the mouth 0.032 mm. wide. Eanging from 0.08 mm. long by 0.06 mm. broad, with the mouth 0.024 mm. wide, to 0.14 mm. long by 0.128 mm. broad, with the mouth 0.048 wide. Locality. — Ponds and ditches in the vicinity of Philadelphia; Swarth- more brick-pond, and ponds on Darby Creek, Delaware County; Morris- ville pond, Berks County; ponds in vicinity of Easton, Northampton County, Pennsylvania; ponds in New Jersey; Spencer pond, Maine; vicinity of Jacksonville, Florida; Fort Bridger and Uinta Mountains, "Wyoming Territory. Bombay, Carter; Germany, Fresenius. Difflug^ia lobostoilla is one of the most common species, and may be found more or less abundantly in the ooze, or among algse, in ponds and GENUS DIFFLUGIA— DirFLUGIA LOBOSTOMA. 113 ditclies where other kinds occur. As usually observed, it is seen lying o^ the side, and it often requires patient manipulation to make it tuyi in such a way as to obtain a view of the mouth, on the peculiar character of which its specific distinction mainly depends. As ordinarily seen, it bears so close a resemblance with the con'esponding views of Bifflugia proteiformis, as described and figured by Ehrenberg,* that it may not only be readily taken for the same, but I have suspected that Ehrenberg may have actually had this animal under observation when he described D. proteiformis. Ehrenberg, however, makes no allusion to the character of the mouth of the latter, and subsequently, in referring to one of the varieties of D. lobo- stoma, described by Mr. Carter, first as D. proteiformis, and then, from the trilobate condition of the mouth, as JD. tricuspis, he does not even hint that the latter is synonymous with his D. proteiformis. f The name of Bifflugia proteiformis is exceedingly indefinite in its application. It was originally applied by Lamarck, f without discrimina- tion, to all the forms figured and described by Leclerc as characteristic of the genus Difflugia.§ Ehrenberg, attributing the name to Lamarck, applied it to a new form, and ascribed one of the forms represented by Leclerc to the same species. || Dr. Wallich uses the name of Bifflugia proteiformis in a sort of generic sense, and regards all other forms of the genus ordinarily recognized as transitional subspecies and varieties.1[ As previously intimated, Mr. Carter applied the name of B. proteiformis to a species, and subsequently, from the trilobate form of the mouth, named it Bifflugia tricuspis.** The late Prof Bailey, of West Point, New York, in his Microscopical Observations made in South Carolina, Georgia, and Florida, mentions the occurrence of B. proteiformis, but gives no clue as to the particular form he viewed as this species.ff Ehrenberg's description of B. proteiformis is too incomplete to deter- mine whether it applies to what I have viewed as the B. glohulosa of Dujar- din, or the present species, which I have named, from the peculiar character of the mouth, B. Idbostoma. I was led to reject Mr. Carter's name of B. tricuspis, evidently applied to the same, as it is objectionable, if we include * Infusionsthierclien, 131, Taf. ix, Fig. i. || Infxisioiistliierchen, 131. + Abh. Ai. Wis. Berlin, 1871, 238, 264. IF An. Mag. if at. Hist, xiii, 1864, 215. t Animanx sans Verfcfebres, ii, 1816. **n)id. xviii, 1856, 128, 221. § M6m. Mus. Hist. Nat. t. ii, 474, pi. 17. tt Smithson. Contrib. ii, 1850. 8 KHIZ 114 FRESH- WATEE EHIZOPODS OF ^OETH AMEEICA. with the species all the varieties in which the number of cusps, or rather lobes, to the mouth, varies from three to half a dozea or more. A variety of the same species, with a five-lobed mouth, is figured and described by Fresenius, and referred by him to the B. oblonga of Ehrenberg.* The reference is, however, improbable, for Ehrenberg, in speaking of the Difflu- gia tricuspis of Carter, remarks that Fresenius regards it as B. oblonga, but adds that he had not perceived a three-lobed mouth to the latter,t from which it may be suspected that no lobes whatever were present, as appears to be the case, if we may found an opinion on the figures of that form in the ' Infusionsthierchen.' The shell of Bifflugia Idbostoma is commonly ovoid, with the mouth situated at the narrower pole. Less frequently it is oval or nearly spherical, or the ovoidal form may be more or less prolonged at the narrower pole, so as to assume a sub-pyriform shape. The mouth may truncate the shell, or it may not interfere with the curvature of the oral pole, or this may more or less protrude so as to form a short neck or rim. Usually the mouth is trilobed, or is bordered with three rounded lobes or sinuses separated by angular points, and resembles the trefoil opening employed in architectural decoration, as seen in figs. 1, 3, pi. XV. The number of lobes of the mouth may, however, vary from that given to half a dozen or more. Next in frequency to the trilobate mouth, according to my experience, is the six-lobed mouth, as seen in figs. 10, 12, and after this comes the quadrilobate mouth, as seen in figs. 6, 8, 1 6. Large specimens, with a many-lobed mouth, approximate- Bifflugia corona, and indeed I have observed so many of intermediate condition in all respects, that there is little doubt that the two species merge into one another. The shell of Bifflugia lohostoma is usually composed of angular quartz- sand, in common with other species of the genus. Barely it is com- posed of diatoms, or diatom-like plates, together with fragments of others, sometimes with variable proportions of quartz-sand. Small shells occa- sionally occur composed of chitinoid membrane with quartz particles incorporated. Individuals in which the shell is composed wholly of quartz- sand are represented in figs. 1-15, pi. XV. * Abh. Senckenl). Naturf. Geselis. ii, 185&-8, 225. ^ Abh. Ak. Wis. Berlin, 1871, 238, 239. GEimS DIFFLUGIA— DIFFLUGIA LQBOSTOMA. 115 Specimens in which the shell is composed of thin an^lar siliceous plates, consisting at least in part of diatoms and fragments of others, found usually in sphagnous swamps, are represented in figs. 18-20. In several instances I have found specimens of large size, especially in ponds of the Uinta Mountains, as represented in figs. 16, 17, in which the shell was composed of rectangular and oval plates defined by interrupted or dotted lines, the nature of which I did not determine. Another variety, observed in a few instances, from Woodstown pond, Gloucester County, New Jersey, had a mammillated shell, as represented in figs. 21, 22. Themtilberry appearance of the shell reminds one of the figure of a form designated by Dr. Wallich as Difflugia ttiberculata. The specimen had a six-lobed mouth with a short rim, but the composition of the shell I failed to make out. In several instances, once at Morrisville pond, Berks County, and' the other in the ditches below Philadelphia, I found peculiar translucent pale yellowish specimens, such as are represented in figs. 25, 26, pi. XVI. The ovoid shell, with trilobate mouth, appeared to be composed of a cancellated membrane, as in the genus Nebela. Rarely, also, I have seen a specimen with trilobate mouth, in which the shell appeared to be composed of flocculent dirt, as represented in fig. 29. A small specimen, such as I have occasionally seen, with trilobate mouth, and with the shell composed of chitinoid membrane, incorporated with a few scattered quartz particles, is represented in figs. 27, 28. This specimen, from Swarthmore brick -pond, accords with the Bifflugia tricuspis of Mr. Carter, described as a smaller and less incrusted- species than B. pro- teiformis, with trefoil opening of the test, measuring ith of an inch, from Bombay, Ehcenberg regards it as a distinct species, and the name has certa,inly precedence of the one under which it is here included, but has appeared to me inappropriate for adoption. In perhaps most cases in which I have observed Bifflugia lohostoma, especially the ordinary form with trilobate mouth, the endosarc has appeared bright green from the presence of chlorophyl corpuscles ; but in many instances all color except that derived from the food has been absent. Bifflugia lohostoma commonly ranges in size from the gi th to the j^^th of an inch. 116 FEESH-WATEE EHIZOPODS OF NOETH AMEEICA. A large specimen, referable to D. lobostoma, from Jacksonville, Florida, is represented in fig. 8, pi. XVII. It had a six-lobed mouth, with deep sinuses, separated by angular points. In all respects it closely resembled one, of which the mouth is represented in fig. 12 of the same plate, of 2>. corona, from Lake Hattacawanna, New Jersey, except that it was devoid of spines to the summit. At the side of the latter it might be regarded as a spineless variety of the same species. Another specimen, from Hammonton pond, Atlantic County, New Jei'- sey, represented in figs. 18, 19, pi. XV, may be regarded as a transitional form from D. lobostoma to B. corona or D. urceolata. The shell is larger than usual in D. lobostoma, is nearly spherical, provided with a short neck and a feebly crenulated mouth, in which the crenulations are seen to be about eleven. It is composed of thin angular plates, apparently consisting of diatoms and fragments of others. As before intimated, Difflugia lobostoma is the commonest of our species, and is found in the superficial mud and flocculent matter of most fresh-water ponds and ditches. I have also frequently found it among the filamentous algae and the materials adherent to aquatic plants. When first noticed after removal to the field of the microscope, it is usually seen lying on the side. Protruding its finger-like pseudopods, commonly about half a dozen, after some apparent struggling it rises on end, generally with the mouth down- ward. On tapping the slide upon which it is examined, it either firmly maintains its position, or withdrawing the pseudopods it falls again on the side, and usually much labor and patience are required to get the creature in such a position as to see the mouth. From the common occurrence of D. lobostoma, with the circumstance that, as ordinarily seen, it so much resembles the B. proteiformis of Ehrenberg, I have been led to suppose that it is the former, which is usually regarded as the latter by authors. I have repeatedly seen Difflugia lobostoma in conjugation, mostly two individuals, but in several instances three together, so as to give a view in outline comparable to the trefoil-shape of the mouth of the commonest variety. DIFFLUGIA ARCULA. Plates XV, flgs. 34-37 ; XVI, figs. 30, 31. Shell hemispheroidal; fundus convex; base inverted, shallow infun- dibuliform; mouth inferior, central, trilobed. Structure of shell usually GENUS DIFFLUGIA— DIFPLUGIA AEOULA. 117 of yellowish chitinoid membrane, mostly with more or less adherent dirt or scattered particles of quartz-sand or diatoms, especially occupying the fundus. Sise. — From 0.112 mm. to 0.144 mm. broad by 0.06 miji. to 0.08 mm. high; mouth 0.028 mm. to 0.04 mm wide. Locality. — Sphagnum of Atco and Absecom, New Jersey; of Toby- hanna, Pokono Mountain, Monroe County, and Broad Mountain, Schuylkill County, Pennsylvania. Difflugia arcula is perhaps an extreme variety of Bifflugia Idbostoma. It is not unfrequent, and appears to be confined to sphagnous swamps, ^n shape, color, and matei-ial of structure, its shell resembles that of an Arcella, as seen in figs. 34-37, pi. XV. Usually it is nearly hemisphe- roidal; but the height is commonly a little greater than half the breadth. The top is evenly rounded and dome-like. The bottom is a broad, shallow, inverted funnel with reflected border. The mouth is central and trilobed; the lobes or sinuses being variably narrowed in degree. See figs. 34-37, pi. XY; figs. 30, 31, pi. XVI. In structure, the shell is composed of chitinoid membrane of difierent shades of straw-color, often with irregular darker spots, apparently as if due to adherent dirt. Frequently, also, it has incorporated particles of hyaline quartz-sand mostly scattered on the sides, or more especially accumulated on the fundus. Sometimes a few diatoms or fragments of these are mingled with the quartz-sand. The specimens observed were always dead, so that I did not ascertain the appearance of the sarcode. The smallest specimen measured ^^gd of an inch broad and ^^d of an inch high; the largest was ^^d of an inch broad and j^th of an inch high. Bifflugia arcula probably merges into B. globuhsa, B. Idbostoma, Ceni/ro- pyxis, and Arcella. DIFFLUGIA CORONA. Plate XVII. Difflugia corona. WalUch: Au. Mag. Nat. Hist. xUi, 1864.— Leidy : Pr. Ac. Nat. So. 1874, 14, 79; 1877 307. Difflugia protdformis, subsp. D. glohularis, var. D. corona. Wallioh : Ibid. Shell spherical or spheroidal, composed of clear angular quartz-sand; fundus with a number of conical spines of the same composition as the rest of the shell; mouth terminal, circular, with the border multidentate or 118 FEESH-WATEE EHIZOPODS OF IfOETH AMEEICA. crenulate. Sarcode colorless; pseudopods many, of the usual form in the genus. Size.— Ranges from (U4 mm. to 0.32 mm. in diameter; mouth 0.06 mm. to 0.18 mm. wide; spines 0.04 mm. to 0.06 mm. long. ioca%.— Ditches near Philadelphia, ponds on Darby Creek, and Swarthmore brick-pond, Delaware County, Morrisville pond, Berks County, Pennsylvania; Atco pond, Woodstown pond, Hammonton pond," Absecom pond, and Lake Hattacawanna, New Jersey; Spencer pond, Maine; Jacksonville, Florida. England, Wallich. Difflii^ia corona, as represented in the figures of pi. XVII, is the most remarkable and beautiful species of the genus. It was first indicated by Dr. Wallich from specimens found in England It is a common Ameri- can species, and is frequent in the vicinity of Philadelphia. The shell of Bifflugia corona is usually nearly spherical, but frequently is shghtly prolonged approaching the mouth. It is commonly one of the smoothest of the genus, though composed of angular particles of quartz- sand in the usual manner. The mouth is circular, and commonly trun- cates the spheroidal shell, or it continues its curvature, or it is somewhat projected. The lip or border of the mouth is dentated or crenulated. The denticles are thick, angular processes, more or less acute, sometimes blunted, concentric, or slightly everted. They range in number from six to sixteen; but the most frequent number is twelve, and usually a larger rather than a smaller number prevails. The intervening notches are thick- edged, as deep as they are wide, and rounded at bottom. The fundus of the shell is furnished with a variable number of acute conical spines. Generally there are from three to seven ; but they range in number from one to eleven. Mostly they form an eccentric circle, widely divergent, nearly equidistant, and usually occupy a position at the upper third of the shell. Often there is a central spine, sometimes longer than the others. Often this is absent, and sometimes it is the only one existing. The spines are straight or slightly curved, sharp-pointed, hollow processes of the shell, with the same composition. The shell is composed of colorless angular quartz-sand, usually with the larger particles scattered, with some appearance of uniformity, and with the intervals occupied by smaller ones. Often, too, larger stones are GENUS DIFFLUGIA— DIFPLUGIA CORONA. 119 ranged near the mouth, and sometimes form a nearly unbroken row. The denticles of the mouth and the spines of the fundus are likewise made up of sand. Not unfrequently the spines end in a single sharp splinter, or flake, which, in many instances, is of so marked a character that one can- not avoid the impression that it has been specially selected. Mostly the denticles and the tips of the spines are colored ferruginous brown, while the rest of the shell is uncolored. As usual in Difflugias, the shell has an uneven surface, varying in this respect mainly according to the proportionate quantity of large and small sand gr-ains entering into its composition. Nevertheless, the grains are united in such a manner that, as before intimatedj it is comparatively one of the least uneven in the genus. Irregular variations from the usual forms of B. corona are occasionall}^ found. In several instances I have seen specimens somewhat compressed and unsyrametrical, probably from accident. Such a one is represented in fig. 11, pi. XVII. In this, also, the spines were disproportionately large compared with their ordinary condition. Sometimes the spines may be more irregularly disposed, out of the usual proportions, more curved, much reduced in size, and rarely nearly obsolete. I have occasionally met with a specimen in which the mouth was more or less oblique or subterminal, and with a single spine terminating the fundus, as seen in fig. 7. This matter brings us to what may be viewed as transitional forms. Fig. 12 represents the mouth of a shell of Diffliigia corona, from Lake Hattacawanna, New Jersey. In all respects, the specimen accords with the commoner forms, but has only six denticles to the mouth. It differs only from the large specimen of Bifflugia lobostoma, of fig. 8, from Jacksonville, Florida, in the possession of spines to the fundus. As we have seen that the number of the spines in B. corona may be reduced from eleven to one, we may regard the specimen of B. lobostoma, just indicated, as a spineless form of B. corona. Thus, no positive character separates Bifflugia corona ironi Bifflugia lobostoma as an independent species. The interior sarcode of B. corona, as visible through its stony wall, appears colorless, with a more or less brownish tinge and darker spots of the same, centrally in the endosarc, dependent on the food. The pseudo- pods present the usual appearance, digitate and palmate, or long and cylin- drical, simple or branching, and ever changing. in length and form They 120 FEESH-WATEE EHIZOPODS OE NOETH AMEEICA. are sometimes extended upward even to the ends of the spines projecting from the fundus. Mostly perfectly clear, under high powers of the micro- scope they appear uniformly and exceedingly finely granular. When much extended, they often exhibit the entrance, along their axis, of coarser granules from the endosarc. Dr. Wallich, who first described B. corona, views it as a variety of what he calls the subspecies Difflugia gldbularis. In the original notice of the latter,* as D. globulosa, Dujardin describes the shell as corneous and nearly globular, and accompanies the account with figures, one of which, representing a side view, is ovoid, with an oval mouth without crenulation. In the 'Histoire Naturelle des Infusoires,' he describes the shell as brown, globular or ovoid, and smooth. In the 'Proceedings of the Dublin Microscopical Club,' 1866, p. 53, it is stated that Mr. Archer, among other Rhizopods exhibited one that he "would refer somewhat doubtfully to Difflugia corona." He remarks, "If this be D. corona, Dr. Wallich's figure is too regular and symmetrical, too diagrammatic, the adherent foreign particles too accurately adapted, and too much of one size, and the horns too short." According to my experience, Dr. Wallich's figure is a fair representation of the species, and Mr. Archer's criticism leads me to suppose that he had under comparison an irregular specimen, and not one of the usual character. Difflugia corona ranges from the ^t^ ^ ^^^ ¥^ of an inch. It is one of the most characteristic and beautiful forms, and is also common in many localities. It is found living in the surface mud at the bottom of ponds and ditches, or among the dirt adherent to submerged aquatic plants. It feeds on algae and apparently also on decaying vegetal matter. DIFFLUGIA CONSTRICTA. Plate XVIII. Jrcella comtricta, Ehrenberg: Abh. Akad. Wis. BerUn, 1841, 410, Taf. iv, i, Fig. 35, Taf. v, Fig. 1. Areella lunata. Ehrenberg: Ibidem, 1841, 410; 1871, 259, Taf. iii, ii, Fig. 3, 4. Arcella Arctiseon. Ehrenberg : Microgeologie, 1854, 108, 171 ; Abh. Ak. Wis. 1871, 258, Taf. iii, ii, Fig. 17. Areella guaUmalensis. Elirenberg : Microgeologie, 1854, 364 ; Ab. Ak. Wis. 1871, 259, Taf. iii, ii. Fig. 16 ; Nordpolarfahit, 1874, Taf. iii, Fig. 35. Difflugia marswpiformis. Wallich : An. Mag. Nat. Hist, xiii, 1864, 241, 244, pi. xvi, flgs. 3-5.— Leidy : Pr. Ac. Nat. Sc. 1877, 307. Difflugia protdformis, sahspeeies D. marmpiformis. Wallich: Ibidem. Difflugia marmpifwmis, variety D. cassia. Wallich: Ibidem, flg. 6. — Leidy: Pr. Ac. Nat. Sc. 1877,321. A. HortuBoehlarmjs constriota. Ehrenberg: Ab. Ak. Wis. 1871, 244. *An. Sc. Nat. viii, 1837, 311, pi. 9, lig. 1. GENUS DIFFLUGIA— DIPFLUGIA OONSTEICTA. 121 A. Sbmwochlamys Iwnata. Ehrenberg : Ibidem, 244, 274. A. Heteroeosmia Arctiaeon. Ehrenberg : Ibidem, 245, 274. A. Helerooosmia gvaUmaleneia.- Ehienberg : Ibidem, 245, 274. Arcclla horeaUs. Ehrenberg : Nordpolarfahrt, 1874, Taf. iii, Fig. 29. Arcella laliceps. Ehrenberg : Ibidem, Fig. 30. Shell laterally ovoid, with the fundus posterior and more or less pro- longed obliquely upward, obtusely rounded and simple, or in the largest forms often provided with from one to half a dozen conical spines. Mouth antero-inferior, large, circular or oval, and inverted, with the anterior lip often prominent. Shell as usually seen (lying on the front, by transmitted light) more or less pyriform, with the narrower part downward and including the mouth, which appears as a clearer transversely oval or somewhat reni- form or circular space ; sometimes in the shorter forms nearly circular or even transversely oval in outline. Shell composed of hyaline quartz-sand, or of chitinoid membrane, usually with variable proportions of scattered mineral particles. Colorless, yellowish, or brown. Interior sarcode transparent and colorless. Si^e. — Spineless specimens range from 0.09 mm. long by 0.078 mm. broad, to 0.232 mm. long by 0.16 mm. broad. The spine-bearing forms range from 0.18 mm. long by 0.12 mm. broad, to 0.34 mm. long by 0.18 mm. broad.* Locality. — The smaller spineless forms are found almost everywhere in moist places; the larger forms, including those bearing spines, are found commonly in the ooze of ponds. New Jersey, Pennsylvania, Maine, Flo- rida, Alabama ; and at Fort Bridger and in the Uinta Mountains, Wyoming: Difflngia constricta, of which many forms are represented in pi. XVIII, is one of the most common species. It holds a slanting position in comparison with that maintained by others ; that is to say, when the ani- mal is erect, as in its ordinary movements, the long axis, corresponding with a line passing from the centre of the mouth to the summit of the shell, is oblique instead of being perpendicular. The inclination of the axis ranges between 30° and 60°. Commonly the shape of the shell is slightly compressed pyriform or ovoid, with the narrower end downward and forward. It is of variable * The length is taken from the anterior lip to the ftindus, as the specimens are usually seen lying on the object-glass of the microscope. The true length would be from the centre of the mouth in the axis of the shell to the fundus. 122 FEESH-WATEE EHIZOPODS OF NOETH AMEEICA. length, and wider from side to side than from before backward. In the lateral view, with the plane of the mouth or bottom of the shell on a level, it appears obliquely ovoid, with the fundus directed backward and upward, and with the fore part of the base or anterior lip usually more or -less prominent. In the front or back view of the shell, as it is ordinarily seen, lying on the object-plate of the microscope, by transmitted light, it appears pyriform, ovoid or spheroid in outline, with a clearer transversely oval or somewhat reniform or round space included within the lower or narrower part and produced by the mouth. See figs. 2, 5, 7, 15, 22. The bottom of the shell is concave, and the nearly circular or oval mouth is inflected and situated above the level of the border of the base. The fundus is usually obtusely rounded and simple, and viewed from behind is transversely oval and flattened below, as seen in fig. 13. In the largest and most elongated forms, the fundus is often provided with from one to half a dozen acute, conical spines. A single spine pro- duces a central, rather abruptly tapering point ; a pair surmount the sides, and a greater number are ranged in a usually more or less regular row. Unsymmetrical forms of Bifflugia constricta are not unfrequent, espe- cially in the larger specimens, both in the shape of the shell and. in the arrangement of the spines, when these exist. The shell is ordinarily composed in the usual manner of other species of the genus ; that is to say, of angular particles of quartz-sand. Sometimes the particles have more or less uniformity ; sometimes heavier grains sur- round the mouth, and not unfrequently also occupy the top of the fundus. When spines are present they have the same composition as the body of the shell ; but a remarkable circumstance is the frequent termination of these spines with a single sharp-pointed and trenchant splinter, as if specially selected for the purpose, and as represented in figs. 56, 57. Earely the shell is composed of chitinoid membrane incorporated with variable proportions of scattered quartz particles, in the form of minute grains or thin plates. Occasionally minute oval pellets, and sometimes dia- toms, enter into the constitution of the shell. The sarcode of Bifflugia constricta, independent of any food contents, is transparent and colorless, and the animal is so very sensitive and indis- posed to protrude its pseudopods, that in most cases it is difficult, in con- GENUS DIFFLUGIA— DIPFLUGIA CONSTEICTA. 123 sequence of the structure of the shell obscuring the interior, to detennine whether the specimens under examination are dead or alive. Bifflugia constrida, in its various forms, is one of the most abundant of species, and appears to be found almost everywhere where moisture and algae are present. Small spineless specimens, cap-like in form, of the variety named by Dr. Wallich Bifflugia cassis, such as represented in figs. 8-34, pi. XVIII, are very common with algae, on the surface of moist earth, in marshy places, in meadows, and in forests. I have found them constantly, in asso- ciation with the common wheel-animalcule and several other rhizopods, about the roots of mosses, and with algae, in the crevices of the pavements in shaded places in the city of Philadelphia. I have even found them among mosses and lichens high up in trees. They also occur frequently among sphagnum. The small spineless forms are frequently of various shades of brown, while the larger ones are usually colorless. The largest varieties and the spine-bearing forms are found in the ooze of ponds. These appear to constitute the variety named by Dr. Wallich Bifflugia marsupiformis. See figs. 35-55. A somewhat peculiar variety, represented in figs. 37-44, I have not unfrequently found among sphagnum. The shell is cap-like in shape, yellowish brown in color, and composed of chitinoid membrane, usually incorporated with variable proportions of scattered sand particles. In the view from the front or back, the shell appears transversely oval, but flat beneath. The mouth is deeply inflected, or forms the smaller opening of an inverted funnel, of which the base of the shell forms the greater opening. Sometimes the fundus of the shell is loaded with comparatively large stones, and rarely the shell is almost devoid of sand particles. This form of shell approximates closely, if it does not really merge into, the spineless variety of Centropyxis. pjither of the names Bifflugia marsupiformis or B. cassis, given by Dr. Wallich, better applies to the species than that of Arcella constricta, given originally by Ehrenberg. The apparent constriction, often absent, is due to the. narrowing of the shell, as seen in the front view, opposite the position of the mouth. The form of Bifflugia consi/ricta repeats that of Trinema enchelys, but 124 FEESH-WATEE EHIZOPODS OF NOETH AMEEIOA. I have not been able to ascertain whether these actually merge into each other. The range in size of Bifflugia constricta is considerable. The smallest measured was ith of an inch long from the anterior lip to the fundus, the breadth was sHghtly less than the length, and the thickness or fore and aft diameter of the fundus ^th of an inch, and the mouth was g^gth of an inch wide. The largest was ^i^th of an inch long from anterior lip to fundus, jl-^th of an inch broad, 255th of an inch thick, and the mouth ^i^th of an inch wide. The spines of the fundus reach a length of g^gth of an inch. DIFFLUGIA SPIRALIS. Plate XIX, figs. 1-23. Diffluffia. Leclerc: M6m. Mus. Hist. Nat. 1815, ii, 474, p]. It, figs. 1 and 4. Difflugia spiralis. Ehrenberg: Moiiatsb. d. Berlin. Aiad. d. Wissens. 1840, 199; Abhand. Akad. Wissens. BerUn, 1871, 274, Taf. iii. Fig. 25-27.— Bailey : Micros. Obs., in Smithson. Contrib. 1850, 41.— Fresenius : Abhand. Senckenb. Naturf. Gesells. ii, 1856-8, 224, Taf. xii, Fig. 37-42.— Pritchard : History of Infusoria, 1861, 553.— Carter: An. Mag. Nat. Hist, xiii, 1864, 18, pi. i, fig. 9.— Wallich: An. Mag. Nat. Hist, xiii, 1864, 215.— Leidy: Pr. Ac. Nat. So. 1874,79; 1877,307. Zccquereusiajurassica. SoMumbergcr : An. Sc. Nat. 1845, 355. Sifflugiaproteiformis, monstrosa. Perty: Kenntniss Meinster Lebensfortaen, 1852, 187, 214, Taf. viii, Fig. 22. Bifflugia Helix. Cohn : Zeitsob. f. wissens. Zoologie, 1853, 261. Difflugia proieiformis, Tar. septifera. Wallicb: An. Mag. Nat. Hist. 1853, xi, 1853, 453, pi. x, fig. 12. JOifflugia proteiformia. WaUieb: An. Mag. Nat. Hist. 1863, xii, 456. Bifflugia protmformis, subspecies B. miiriformia, Yar. /3. B. spiralis. WaUich: An. Mag. Nat. Hist. 1864, xiii, 1884, 240, pi. xvi, figs. 24, 25. B. Cwticella spiralis. Ehrenberg : Abh. Ak. Wis. Berlin, 1871, 247. Shell retort-shaped, usually with a laterally compressed spheroidal body, and a short, wide, cylindroid neck, obtuse fundus, and terminal circu- lar or slightly oval mouth. A partition occupying the interior of the shell, defining the neck from the body, and giving to the shell by transmitted hght the appearance of a single turn of a spiral. Structure of the shell variable; frequently of quartz-sand, often of pecuHar elements, or of chit- inoid membrane incorporated with various extraneous particles. Sarcode colorless; pseudopods as usual in the genus. Sise.— Length 0.096 mm. to 0.188 mm.; breadth of body 0.068 mm. to 0.164 mm.; thickness 0.068 mm. to 0.136 mm. Locality. — Lakes, ponds, and ditches. Pennsylvania, New Jersey, Rhode Island, South Carolina, Georgia, Florida, Alabama, and the Uinta Mountains of Wyoming Territory. Difflngria spiralis, a common and pretty species (figs. 1-23, pi. XIX), is one of the most remarkable forms of the genus, and is also the most GENUS DIFFLUGIA— DIFPLUGIA SPIEALIS. 125 variable in the structure of its shell. It is one of the original forms described by Leclerc, in 1815, under the generic name alone. Though not strictly correct to call it spiral, the construction of the shell, especially when viewed by transmitted light, gives rise to such an impression, and thus led Ehren- berg so to name it, and likewise Bailey after him, apparently without knowing that the former had done so. In Difflugia spiralis we may recognize one of the enigmatic rhizopods, described, without illustrations, by Schlumberger, in 1845, in the 'Annales des Sciences Naturelles.' I refer to the Lecquereusid jurassica, described as having " a somewhat depressed ovoid-globular retort-shaped shell with a short, wide neck and a terminal circular aperture, from which project thick, cylindrical, blunt pseudopods." The shell of Difflugia spiralis is retort-like or flask-shaped, with a usually compressed spheroidal body, and a short, wide, cylindroid neck, which is commonly produced a little more from one side than the other of the shell. The body and neck are, however, quite variable in their exact form and proportions. Commonly the larger specimens with a stony structure accord with the general form indicated. Smaller specimens usually have a proportionately, and often absolutely, longer neck and a more spherical, uncompressed form of body. The neck is mostly straight, but is sometimes slightly bent or curved. Grenerally it is evenly expanded where it joins the body, but is frequently inflated more to one side. The mouth is terminal, circular, or slightly oval, and is neither contracted nor expanded at the border. The shell, as ordinarily viewed lying on one of the usually broader surfaces, exhibits a dark line, indicating the presence of an interior partition, which starts from the bottom of the neck on one side and extends in a more or less oblique direction or curve upward toward the opposite side. In some specimens, the partition appears to extend from one half to two thirds way across the shell, and in others nearly or quite completely across in a sigmoid line to the opposite side. The partition apparently continues inwardly the curvature of one side of the body of the shell, and thus gives rise to the impression that the latter makes a spiral turn. Ordinarily the structure of the shell so obscures the partition from view that a satisfactory idea of its exact form and relations cannot be obtained. In most instances in smaller and more Iranslucent specimens, in which the 126 FEESH-WATEK EHIZOPODS OF NORTH AMERICA. partition could be distinguished, it appeared to be a crescentoid plate, with a large circular aperture between its upper part and the contiguous portion of the shell. In other instances, the aperture seemed to pass through the upper part of the partition itself. • In many specimens, the neck is more or less defined from the body of the shell by a narrow constriction in the line of the partition, especially in those in which the latter extends completely across. The structure of the shell of Difflugia spiraJds is of more variable char- acter than in any other species of the genus. Frequently it is entirely composed of angular, colorless quartz-sand, as in the species of Difflugia generally, and as seen in figs. 1-3, 6, pi. XIX. In these specimens, also, the usual varieties in arrangement occur, some being constructed of particles of some uniformity of size, small or large, while others are composed of scattered coarser particles, with the intervals filled in with smaller ones. Sometimes there is an accumulation, especially of larger stones, centrally on the broader surfaces of the shell, as seen in figs. 4, 5. The former figure represents a large specimen, in which the shell was mainly composed of thin, narrow, rectangular plates, mingled with some diatoms, and the central portion of the broader surfaces of the body was occupied by large particles of quartz-sand. A singular variety is that in which the shell is composed of short vermic- ular bodies closely laid together, as represented in figs. 7, 9—11. The same form is described by Dr. Wallich as occurring in England. The vermicular bodies are transparent and colorless, but when viewed by reflected light present a silvery white lustre. Dr. Wallich calls them chitinous pellets. Occasionally I have found specimens composed of similar bodies sepa- rated by marked intervals, and apparently imbedded in a homogeneous membrane, as represented in fig. 8. Other varieties of shells, related with those last indicated, consisted of a net-work of apparently the same nature as the vermicular bodies, as seen in fig. 12, or of minute scattered corpuscles, as seen in fig. 13. "With these shells, as represented in the two figures just referred to, there were incor- porated scattered particles of quartz-sand. Another interesting variety observed is one in which the shell was mainly constituted in the usual way of a stone-work masonry, but had the neck composed of vermicular bodies, as seen in fig. 5. GENUS DIFPLUGIA— BIFELUGIA SPIRALIS. 127 A singular variety is represented in figs. 14, 16, in which the shell is composed of narrow plates or rods mostly in small parallel groups of twos •and threes or more, and laid closely together in every direction. This is probably the kind to which Schlumberger refers in his account of Lecque- reusia jurassica, in which he says the shell is composed of a paste of minute bacillar bodies. Small forms of Bifflugia spiralis are not uncommon in which the shell is composed of transparent chitinoid membrane incorporated with variable proportions of linear bodies, diatoms, and sand particles, as represented in figs. 16-22. A curious specimen, of large size, represented in fig. 23, was composed of irregularly rounded or oval bodies containing a central nucleus. The nature of these bodies I did not determine. The sarcode of Bifflugia spiralis is colorless, independently of the color given to the endosarc from the presence of food. In the more translucent specimens it can often be detected as a spheroidal mass of variable size occupying the body of the shell, with a narrow neck passing off from one side, in a retort-like manner, and extending through the aperture of the partition, and thence gradually widening to the mouth. The food usually gives to the endosarc a yellowish or pale brownish hue, which is sometimes mingled with gi-een and other colors. The pseudopo'ds in num- ber, form, and changes, are of the same character as in other species of the genus. The size of Bifflugia spiralis ranges from the ith to the jggth of an inch. Bifflugia spiralis may be regarded as the oldest known species, and, as previously intimated, was described and figured by Leclerc in 1815. He represents two varieties; one in which the shell is composed of quartz-sand, the other in which it appears to be composed of chitinoid membrane. He also represents two individuals united, mouth to mouth, in the condition usually indicated as that of conjugation. Perty describes and figures the same species, but regards it as a mon- strosity of Bifflugia pyriformis, in which view he is sustained by Dr. Wallich. \ can see no reason why Bifflugia spiralis should be considered a monstrosity any more than any other recognized form of the genus. Bifflugia spiralis is a common species, but I have found it especially 128 PEESH-WATEE EHIZOPODS OF NOETH AMEEICA. abundant in the ponds of sphagnous and cedar swamps in New Jersey, where it is also to be obtained, in the greatest variety of form, in association with D. pyriformis, B. urceolata, etc. The habits and food are the s^me as in other species generally. I have occasionally observed two individuals of Bifflugia spiralis applied together, mouth to mouth, in the manner first described and figured b^ Leclerc, and as represented in fig. 3, pi. XIX. This condition I have not been able to discover leading to any important result, and I may say the same of other species of Dif&ugia seen in conjugation. In one instance I saw two small individuals applied to the mouth of a third and larger individual, and in another instance I saw three small individuals in like manner applied to a larger one. In the instance represented in the figure, on focusing the conjugating pair so as to see the contents, they were observed to flow from one to the other and back again. After about half a dozen repetitions of the flow and ebb, the contents, apparently equally divided in the two shells, remained quiescent for a time, and then the two individuals separated and moved away in the usual manner. The construction of the shell prevented the determination of any change within, even if such had taken place. HYALOSPHENIA. Greek, liualoB, crystal; tphen, a wedge. Hyalosphenia: Stein, 1857. JHfflugia: Tatem, 1870. Catharia: Leidy, 1874. Shell compressed ovoid to pyriform, composed of transparent structure- less chitinoid membrane; mouth terminal, inferior, transversely elliptical. Sarcode mass occupying the interior of the shell to a variable extent, attached to its inner surface by divergent threads and also connected to the border of the mouth; composed of pale granular protoplasm mingled with colorless or colored corpuscles, or both together. Nucleus large, and cen- trally situated in the fundus of the sarcode. Contractile vesicles several, occupying a position between the former and the periphery of the fundus. Pseudopods few, digitate. GENUS HYALOSPHENIA— HYALOSPHENIA CUEEATA. 129 HYALOSPHENIA CUNEATA. Plate XX, flgB.1-10. Hyaloaphmia ouneala. Stein : Sitzungsb. Bolim. Akad. Wissens. 1857. Diffiugia ligata. Tatem : Month. Micros. Jour, iv, 1870, 313, pi. Ixviii, fig. 1. Caikaria ligata. Leidy : Proc. Ac. Nat. Sc. 1874, 79. Syalosphmia lata. ScLulze: Aichiv mikr. Anat. xi, 1875, 335, Taf. xviii. Fig. 15, 18. — Archer: Quart. Jour. Mic. So. 1877, 110. Eyalosphenia ligata. Leidy: Pr. Ac. Nat. So. 1875, 415; 1876,197. Shell compressed ovoid, with the narrower part conical and truncate at the oral end, laterally and at the fundus convex ; mouth terminal, oval. Shell composed of delicate, transparent, colorless, and structureless chiti- noid membrane. Sarcode mass colorless, pyriform, and attached by threads of ectosarc to the interior of the shell; pseudopods digitate, usually not more than one or two. Sise. — Length 0.06 mm. to 0.076 mm. ; breadth 0.044 mm. to 0.06 mm. ; thickness 0.02 mm ; breadth of mouth 0.016 mm. by 0.012 mm. Locality. — Lansdowne station spring, on Westchester railway, five miles from Philadelphia. Hyalosphenia cniaeata, figs. 1-10, pi. XX, is compressed ovoid, and in the view of the broader side presents a transversely convex fundus and more or less tapering lateral borders, which may be plane, convex, or con- cave in their descent to the mouth. The narrower view of the shell is also obtusely rounded at the fundus and tapering at the sides. The mouth is terminal and oval, with obtusely rounded commissures. The shell of H. cuneata consists of delicate, transparent, colorless chitinoid membrane without trace of definite structure. It is sometimes sufiiciently delicate to be bent by the tension of the threads of ectosarc attached to it within. In one specimen, the broad sides of the fundus appeared to be bent inward by the tension of these threads, as seen in the lateral view, fig. 5. In another specimen, the tension of the threads appeared to indent every point of attachment, as seen along the border in fig. 1 . The size of the shell in several specimens ranged from ^^th to gi^th of an inch in length, by ith to ^^ih of an inch in breadth, and about ^th of an inch in thickness. The mouth measured about the ^^^ih. of an inch wide. 9 EHIZ 130 FEESH-WATEE EHIZOPODS OP NOETH AMEEICA. The sarcode in the few specimens observed occupied about one half of the interior capacity of the shell. It was inverted vase-like in shape, attached at the border of the mouth, gradually contracting and then expanding again within the body. It was attached by long diverging threads of the ectosarc to the sides and fundus of the shell. The sarcode is colorless, and its basis consists of a pale, finely granular protoplasm. Imbedded in the body, toward the fundus of the shell, it contains a large, faintly granular and globular nucleus, from g^th to g^th of an inch in diameter. At the periphery of the body, contiguous to the nucleus, two or three contractile vesicles may be visible at once. Around, but especially below, the position of the nucleus, the endosarc contained a midtitude of darkly outlined granules, and a variable number of larger, clear, well-defined globules, oil-hke in appearance. A few pale vacuoles and small brown food masses were likewise visible. Usually S. cuneata puts forth but a single digitate pseudopod, but occasionally two and less rarely three are emitted. They present the com- mon form and the scarcely perceptible granular character observed in related animals. H. cuneata, from its great transparency, would be admirably adapted for the study of the various life phenomena of its kind, but unfortunately the creature appears to be exceedingly rare. In four years I found only half a dozen individuals, and all these were obtained from the same locality, a spring, in which grew water-cress, near Lansdowne station, on the West- chester railway, a few miles from Philadelphia. In one instance two individuals were found in conjugation, and when first observed they presented the appearance seen in fig. 6. The sarcode of both was continuous at the mouth of the shells ; but in one of these it was less than a fourth of the quantity in the other. A moment after, the sar- code was observed to flow from the larger to the smaller portion until the two became equal in size, and assumed each a trilobate form, as seen in fig. 7. A fourth lobe was produced in one portion of the sarcode, and then the lobes became extended in both so as to form an attachment to the sides and fundus of the shell, as seen in fig. 8. Shortly after, one portion of the sarcode narrowed its connection with the other at the mouth of the shell, then detached itself and shrunk away, as represented in fig. 9. At this time the specimens were accidentally lost ; but several hours later, one of the GENUS HYALOSPHEOTA— HYALOSPHEKLA PAPILIO. 131 individuals was found again, and presented the appearance seen in fig. 10, with the sarcode contracted into the fundus of the shell. From first to last a nucleus appeared to be absent in the sarcode. The endosarc contained fine granular matter, coarser, darkly defined granules, oil-like globules, clear vacuoles, and a few brown food particles. Hyalosphenia cuneata, with this name, was first described by Stein. What appears to be the same was afterward described by Tatem, in Eng- land, under the name of Difflugioi ligata. Schulze subsequently described what he regards as a distinct species from that of Stein under the name of Hyalosphenia lata. I have not access to the description of the latter author; but from its quotation by Schulze I cannot detect sufficient difference to distinguish two species. Stein remarks that in H. cuneata the animal can abruptly and quickly separate from the mouth of the shell and retract to the bottom. Schulze remarks that in II. lata he never observed such a sudden contraction as this. That this apparent difference of habit has no specific value is shown in the fact, that most lobose rhizopods, when disturbed, may retract their pseudopods, but retain the connection of the sarcode mass with the mouth of the shell, notwithstanding the rudest shaking, while at other times any of them may and will sever the connection and quickly retreat to the fundus of the shell. The specific names of cuneata, ligata, and lata are expressive of charac- ters common to any or all the examples described by Stein, Tatem, Schulze, and myself. HYALOSPHENIA PAPILIO. Plate XXI. Difflugia (Catltaria) papilio. Leidy: Pr. Ac. Nat. Sc. 1874, 156. Hyalosphenia papilio. Leldy: Pr. Ac. Nat. Sc. 1875, 415; 1876, 197. Shell compressed oblong ovoid, or occasionally compressed pyriform; in the broader view, with the fundus transversely convex and the sides gradually tapering to the slightly convex oral end, or with a pyriform out- line; in the narrower view, with the fundus angularly rounded and the oral end notched. Mouth transversely oval, with rounded commissures. Shell composed of transparent, yellowish chitinoid membrane. Sarcode with bright green endosarc from the presence of chlorophyl; the mass 132 FEESH-WATEE EHIZOPODS OF NOETH AMBEICA. attached by divergent threads to the summit and sides of the shell; pseu- dopods colorless, digitate, up to half a dozen in number. Sue.— From 0.108 mm. to 0.14 mm. long, 0.068 mm. to 0.084 mm. broad, 0.032 mm. to 0.04 mm. thick; and the mouth end from 0.032 mm. to 0.04 mm. broad and 0.008 mm. in the opposite diameter. ioca%.— Abundant in the moist sphagnum of sphagnous swamps of Pennsylvania and New Jersey. Tobyhanna, Pokono Mountain, Monroe County; Broad Mountain, Schuylkill County, Swarthmore, Delaware County, Pennyslvania ; Absecom, Atlantic County, Longacoming, Ham- monton, Atco, Malaga, Vineland, etc.. New Jersey. Hyalosphenia papilio is common and at times exceedingly abundant in moist bog-moss or sphagnum, in sphagnous swamps, but is not found in ponds except accidentally. No other lobose rhizopod has more impressed me with its beauty than this one. From its deHcacy and transparency, its bright colors and form, as it moves among the leaves of sphagnum, desmids, and diatoms, I have associated it with the idea of a butterfly hovering among flowers. From its comparative abundance, the readiness and certainty with which it may be obtained and preserved, and from its transparency, which allows its structure to be well seen, it is peculiarly well adapted for the study of the life-history of its order. I have collected it from early spring to late autumn, and have retained it alive in sphagnum, in a. glass case, through the winter. During the Christmas holidays, I have repeatedly exhibited it, in the living condition, to the admiration of friends.* * This interesting Ehizopod, found together with a profusion of other remarkahle microscopic forms of both animal and vegetal life, of which many are novel and yet undescribed, recalls pleasing recollections of excursions into the sphagnous bogs, cedar swamps, and pine barrens in the southern region of New Jersey. These localities have special charms for the botanical student on account of the diversity of beautiful and interesting plants they produce. In proper season, in most places, they are redolent with the rich perfume of the Magnolia glauca and the fragrance of the Clethra alnifolia. In early spring, the groimd is adorned with bright patches of the little Pyxie, Pyxidanthera barhulata, and Sand-Myrtle, Leiophyllum buxifoUum. Later, the swamps display an abundance of Meloniaa hdlata, and still later, many other Uliaoeous plants, as Zygadetma Umanthoides, Narthedum ametioanum, besides more common ones. Eich are the woods and swamps in Orchids of the genera Cypripedium, Goodyera, Spiranfhes, Liparis, Hdbenaria, Calopogon, Pogonia, and Arethuaa. On dry banks, amidst a host of Vacciniums and other ericaceous plants, are conspicuously seen the spikes of white flowers of the grassy-looking Xeropfvyllum aaphodeloidea ; while the bogs below are as conspicuously dotted with the curious green and purple Pitcher-plant, Sarracmia purpurea, nestling among sphagnum, and entangled among Cranberry and Sundews, Droaera filiformia, etc. In many places occurs the singular grass, with its underground fruit, the AmphioarpumPwaUi; and in more restricted localities appears the rare little fern, the ScMacm puailla. Upward of thirty years ago, while examining the structure of sphagnum, my attention was distracted by the movements of a singular animal, whose character and aflSnities I did not then recog- nize. September 9th, 1873, the fiftieth anniversary of my birth, a friend, Clarence S. Bement, presented GENUS HYALOSPHBNIA— HYALOSPHENIA PAPILIO. 133 The shell of H. papilio, pi. XXI, is usually compressed oblong ovoid, but occasionally is compressed pyriform. The compression is about equal to one half the greater diameter. The transverse section, figs. 14, 15, is elliptical, with rounded angular poles. Viewed on the broader surface, figs. 1, 3-5, 7, 11-13, the outline is broadly convex at the fundus, from ■ which the sides slant in a straight or nearly straight line close to the mouth, where they are commonly slightly everted. The lower extremity or line of the mouth is transversely slightly convex. In a comparatively few specimens, in the- view of the broad surface of the shell the outline is decidedly pyriform, as seen in fig. 10. In the view of the narrower side of the shell, the outline is flask-shaped, with the fundus rounded, obtusely angular, or slightly prolonged; and the oral end appears as a concave notch. See figs. 2, 6, 8, 9. The mouth is inferior, terminal, and transversely elliptical, with rounded commissures, and is convex in the wider and concave in the narrower direction. The shell is buff- or straw-colored, of lighter or darker shade, and rarely nearly colorless. Among thousands of specimens from different localities, I do not recollect meeting with one in which at least a trace of yellow could not be detected. As in other species of the genus, it is perfectly transparent and structureless, nor did I ever find a specimen with adherent extraneous bodies of any kind. The thickness of the shell is pretty uniform, but is slightly greater around the mouth. In the view of the broader side of the shell, along the border of the fundus, there may be detected from two to half a dozen minute apertures, around which the shell is slightly thickened. These appear to serve for the ingress and egress of water accompanying the protrusion and retraction of the pseudopods. See figs. 1, 3-5, 7, 10-13. The shell of Hyalosphenia papilio exhibits but little variation in size. It ranges from ~^\h. to gj^th of an inch in length by jg^th to ^th of an inch in breadth, and ^th to ith of an inch in thickness. The mouth ranges from ith to ^^ of an inch in breadth. me with a small Hartnack microscope, which, from its convenient size and form, I kept on my stndy table. From time to time! was led to make observations on Fresh- water Ehizopods detected in sedi- ments collected vx the vicinity of Philadelphia. A year later, in examinlag water squeezed from sphag- num obtaiaed at Absecom, I observed many individuals of the same singular animal above indicated, but now, understanding its nature, I described it as Difflugia papilio: It was the rediscovery of this beau- tiful form which impelled me tp pursue the investigations which constitute the material of the present work. 134 FEESH-WATEE EHIZOPODS OP NOETH AMEEIOA. The sarcode of Myalosphenia papilio I have never seen entirely filling the shell. Its proportionate size with the capacity of the latter varies very much, the difierence apparently being more or less dependent upon the amount of nutriment taken by the animal. Thus I have observed, in the summer months, when apparently the conditions* of life were most favor- able to the animal, that the sarcode mass was largest, and most nearly filled the shell, as seen in fig. 1. Under less favorable circumstances the sarcode was smaller ; and sometimes the animal would impress me with the idea of being starved, when the sarcode mass would occupy less than half the capacity of the shell, as seen in fig. 4 In the view of the broad surface of H. papilio, the sarcode mass usually appears pouch-like in outline. The upper part is ovoid; the lower part is as wide as the shell contiguous to the mouth, and the intermediate part is contracted. In the view of the narrow side of the animal, the sarcode mass touches the shell laterally, and appears therefore to fill it more in the less than in the greater breadth. Diverging processes of the ectosarc fix the sarcode mass to the sides and fundus of the shell. These processes, of course, vary in length in proportion as the sarcode mass diminishes or increases. They are conical extensions of the ectosarc, more or less tapering to filaments, and are usually simple, but sometimes furcate at their outer connection. They are of the nature of pseudopods, and may be detached from the shell and withdrawn into the sarcode mass, while new ones may be projected and extended to become attached to the shell. The sarcode of H. papilio is remarkable for the quantity of chlorophyl which enters into its constitution. I have never met with a living speci- men of the animal in which this material was absent. It is of a bright green color, like that of the green fresh-water polyp Hydra viridis, and occurs in spherical corpuscles ranging from j^„th to the JLth of an inch in diameter. They are usually so numerous as to obscure all the other con- stituents of the sarcode; but almost invariably this is free from them in the vicinity of the mouth. . The basis of the sarcode is the usual faintly granular coloriess proto- plasm mingled with larger and more distinct granules. The ectosarc every- where appears coloriess and clear or faintly granular. The interior of the sarcode mass near the upper part is occupied cen- GENUS HYALOSPHENIA— HYALOSPHENIA PAPILIO. 135 trally by a large, spherical, clear or pale granular nucleus ; in different specimens ranging from about ji-^tli to j^th of an inch in diameter. In the vicinity of the nucleus, at the periphery of the sarcode mass, there may be detected several contractile vesicles. From two to four are frequently seen at the same time together. They generally expand to about 2^th of an inch in diameter before collapsing. Below the position of the nucleus, between it and the clear sarcode contiguous to the mouth, the endosarc is occupied by variable quantities of brownish food-balls, vacuoles, and occasionally distinct algous forms, intermingled with the constituent elements. Green algse swallowed as food, unless of comparatively large size and more peculiar shape, are not usually distinguishable among the materials of the endosarc in consequence of their being obscured by the abundance of constituent chlorophyl corpuscles. Among them there may occasionally be seen a diatom, a desmid, or a fragment of an oscillaria. The endo- chrome of the alga?, as a result of digestion, appears to become shriveled and assumes a decidedly yellowish or reddish-brown hue. The brownish food-balls vary in quantity and size. They are mostly granular, but sometimes have an oleaginous appearance, and lie free in the endosarc or are contained in vacuoles. They appear to be accumulations of food in the process of digestion, or the remains of food which have undergone digestion and are ready to be discharged. The vacuoles vary in number and size, sometimes few, sometimes many, and ranging from ^^h. to fo^ooth of an inch They appear as globules of clear colorless liquid, of pale colorless granular matter, or of colored food- balls surrounded by a stratum of either or both of the former. At times one or more of the vacuoles may be seen slowly approaching the mouth of the shell, on reaching . which their contents are discharged. Food-balls, in like manner, without being enclosed in vacuoles, may be seen pursuing the same coui'se. In the vicinity of the mouth not unfrequently vacuoles may be seen to appear, to gradually enlarge, and then collapse, in the manner of the con- tractile vesicles so constantly occupying a position at the upper part of the sarcode mass. With the other materials of the endosarc there are numerous colorless well-defined granules which resemble starch, also manj^ small pale globules 136 FEBSH-WATEE EHIZOPODS OF NOETH AMEEICA. resembling vacuoles, and in addition oil-like globules of various sizes, sometimes colorless and sometimes yellowish in hue. These latter mate- rials especially are obscured by the chlorophyl corpuscles. The pseudopods are digitiform and from two or three to half a dozen or more in number. They sometimes extend to a length of g^^th of an inch with a thickness of gJ^th of an inch. They are usually simple, but occa- sionally branch, and are blunt at the end. They are colorless, and with high powers can be seen to be finely but faintly granular throughout. The coarser granules of the endosarc do not enter them. As the pseudopods protrude, the mass of the sarcode in the interior of the shell proportionately diminishes, and the threads of attachment are put to a greater stretch. When the animal is disturbed, the pseudopods are retracted, but the sarcode mass commonly retains its attachment to the mouth of the shell. Occasionally, however, when the animal is suddenly or rudely disturbed, the sarcode mass retreats far into the shell, as repre- sented in fig. 5. In proportion as the sarcode retracts or extends, the attaching threads shorten or lengthen. Not unfrequently, but especially in October and November, and also in the winter months, in sphagnum preserved in a moderate temperature, specimens of II. papilio are to be seen in which the sarcode mass forms a compressed spheroidal ball lying completely quiescent within the shell, as represented in figs. 7-11. The ball, in the narrower view of the latter, is seen to touch the sides, but in the broader view does not extend to the lateral borders. The ball ranges from gi^th of an inch to gj-^th of an inch in breadth, and g^th to ith of an inch in thickness. Generally it is a little greater in its longitudinal than in its broader transverse diameter. The constitution of the ball appears to be nearly the same as the sarcode mass in the active animal, but is devoid of the materials recognized as food, and also presents no vacuoles nor contractile vesicles. It is bright green from the presence of abundance of chlorophyl corpuscles, which exist in the same proportion as usually observed in the active condition of the animal. A central clearer spot would appear to indicate the retention of the nucleus. The exterior of the ball is cofiaposed of a layer, of variable thickness, of colorless, faintly granular ectosarc, not defined from the granular endosarc extending into the mass of chlorophyl corpuscles. Occasionally the green sarcode ball is invested by a more distinct and colorless membrane. GENUS HYALOSPHENIA— HTALOSPHENIA PAPILIO. 137 Not unfrequently specimens of the kind just described are seen with one or more globular masses of granular matter, colorless or colored yel- lowish or brownish, lying between the green sarcode ball and the mouth of the shell, as represented in fig. 10, which I have supposed to be excre- mentitious. In several instances I have seen an animal withdraw its pscu- dopods, retreat deeply into the shell, retract its threads of attachment, and assume the form of an oval or spheroidal ball. -- This would subsequently discharge several masses of excrementitious matter of the kind indicated, and become proportionately reduced in size. In many specimens with the sarcode in the condition of a quiescent ball, the mouth of the shell appears to remain open ; in others it is closed by a sort of gelatinoid operculum, as seen in fig. 11. In one instance observed, as seen in fig. 9, the lips at the mouth of the shell were in close apposition, and cemented together by the material of the oper- culum. I have repeatedly met with specimens of H. papilio, as represented in fig. 12, in which the shell contained nothing excepting a quantity of scat- tered bright green chlorophyl corpuscles, in all respects like those ordinarily observed in the sarcode mass of the animal. I have further repeatedly observed specimens in which the shell con- tained a variable number of globular, granular, colorless corpuscles, of nearly uniform size in the same specimen, but of different sizes in different ones, as represented in fig. 13. The nature of these bodies I have not determined, nor whether they actually pertain to the Hyalosphenia ot belong to some parasite, but I have suspected them to be spores of the former. H. papilio in comparison with many other rhizopods is of remarkable uniformity in size, shape, and constitution. Though I have seen thousands of specimens, from different localities, in mountainous regions, and nearly at the sea-level, I have observed but trifling variation. I never have seen anything like decided transitional forms, never any with the shell positively colorless, and not one in any condition, whether of activity or quiescence, in which the Sarcode was devoid of the fchlorophyl corpuscles. As previously intimated, and for the reasons given, I have considered Hyalosphenia papilio peculiarly well adapted for study, and I have looked hopefully forward to it as a means of throwing light upon the modes of 138 FEESH-WATBE EHIZOPODS OP NOETH AMEEIOA. reproduction of the shell-covered rhizopods in general, but up to the pres- ent time I have been disappointed. Among the multitude of specimens I have seen I never observed a pair in the position which is commonly viewed as that of conjugation, and regarded as having some relation with reproduction. HYALOSPHENIA TINCTA. ■ Plate XX, figs. 11-18. Shell compressed pyriform, variable in the relation of breadth to length ; in transverse section compressed oval ; composed of pale yellow, transparent, structureless, chitinoid membrane ; mouth transversely oval. Sarcode colorless ; pseudopods digitate, usually two, three, or more. Sise — Smallest specimen, 0.076 mm. long, 0.056 mm. broad, 0.028 mm. thick, with the mouth 0.02 mm. by 0.008 mm. ; second specimen broader than long, 0.06 mm. long, 0.08 mm. broad, with the mouth as in the former ; third specimen, 0.08 mm. long and broad, 0.0. 6 mm. thick, and mouth same as in former ; largest specimen, 0.092 mm. loug, 0.064 broad, and mouth as in the others. Locality. — ^Abundant in the sphagnous swamps of Tobyhanna, Pocono Mountain, Monroe County, Pennsylvania; found also in the sphagnum near Kirkwood station, on the Camden and Atlantic railway, New Jersey. Hyalosphenia tincta, figs. 11-18, pi. XX, is closely related with H. cuneata, but from its more pyriform shape, pale tinted shell, and living in- sphagnum instead of ponds, I have regarded it as distinct. The shell is compressed pyriform, with a very short neck, usually with little difference between the length and breadth. It is composed of pale yellow or straw-colored transparent chitinoid membrane, without trace of definite structure. It is thicker than in E. cuneata, and is therefore less flexible. At the lateral borders, usually below the middle, it presents a pair of minute pores for the ingress and egress of waten Sometimes another pair of similar pores are found along the same border above the middle. See figs. 11, 12, 14, 16, 18. In transverse section, the shell is laterally compressed oval, with obtusely rounded poles. The mouth has the same form, and is slightly directed upwardly toward the commissures. The size of the shell differs, but little, . though there is considerable GENUS HYALOSPHENIA— HYALOSPHENIA TINOTA. 139 variety in the relation of the greater breadth to the length. Most frequently the specimens observed were quite or nearly equal in length and breadth. Specimens of usual size ranged from g^th to g^th of an inch in length and breadth, with rather less than half the thickness. The mouth is about j^th of an inch in breadth and ^Jth. of an inch in the short diameter. The sarcode is colorless and finely granular, and usually contains a multitude of large colorless globules, which are scarcely distinguishable as vacuoles, food-balls, or contractile vesicles. The latter were only to be recognized by looking for them in the usual position, along the border at the fundus of the sarcode mass. A nucleus is present, but is obscured by the surrounding granules and globules. Viewed laterally, or from the extremities, the sarcode mass was observed to touch the broader sides of the shell; but more or less vacancy was left between it and the narrower sides. The lateral borders and fun- dus etf the mass are attached in the ordinary manner to the inner surface of the shell by threads of the ectosarc. The pseudopods are commonly two or three in number, thick, digitate and simple, but sometimes are more numerous and branching. , Some individuals of this species appeared to be particularly irritable, and tapping the glass upon which they .were placed would not only cause them to retract their pceudopods, but also to separate from the mouth of the shell and retreat into its fundus. In the contraction of the sarcode mass it would assume a spheroidal form, but not withdraw the threads of attach- ment to the sides and fundus of the shell. After a few moments of rest, the sarcode would again descend and establish an attachment to the mouth of the shell, and once more protrude its pseudopods. In one individual, the sarcode mass actually protruded its pseudopods before the body was extended to the mouth of the shell, as represented in fig. 12. Hyalosphenia tincta I found abundantly in moist sphagnum, of the large sphagnous swamps, at Tobyhanna, on the Pokono Mountain, Monroe County, Pennsylvania, in July, 1876. Later I found it, though rarely, in sphagnum, near Kirkwood station, on the Camden and Atlantic railroad, New Jersey. I was at first disposed to view Hyalosphenia tincta as being the same as S. cuneata. They have nearly the same size and form; but the difierence in color of the shell and the difference in the character of the locality they inhabit have led me to regard them as distinct. 140 FEESH-WATEE EHIZOPODS OP NOETH AMEEICA. Associated with Hyalosphenia tincta, I observed a number of speci- mens, of the same sizes, variations in form, and color, but in which the shell exhibited more or less evidence of areolation. In some, the appearance was exceedingly indistinct; in others, it was quite positive, and these latter had then all the characters of a species of another genus, which I have named Nehela flabellulum. Those with the indistinct appearance of areola- tion weie evidently" transitional varieties toward the latter. I have observed sufficient variation in specimens to suspect it probable that Hyalosphenia tincta merges into H. cuneata, and likewise into H. elegans and H. papilio. HYALOSPHENIA ELEGANS. Plate XX, figs. 19-29. Diffiugia {Calharia) elegans. Leidy: Proc. Ac. Nat. So. 1874, 156; 1875, 415. Shell compressed flask-shaped; in the view of the broader side, with an oval body and long cylindroid neck, slightly widened at the oral end, which is convex downward; in the view of the nan-ower side, long elliptical, and tapering to the oral end, which is deeply notched. Shell composed of pale brownish, transparent, structureless, chitinoid membrane, which is impressed with longitudinal rows of hemispherical pits. Sarcode colorless, attached by threads to the sides and fundus of the shell; pseudopods digi- tate, usually three or four in number. Sise.— Length from 0.088 mm. to 0.108 mm.; breadth of body 0.064 to 0.04 mm.; thickness of the same 0.02 to 0.028 mm.; breadth of neck and oral end 0.016 to 0.02 mm.; short diameter of oral end 0.008 mm. ioca%.— Abundant, in association with Hyalosphenia papilio, in sphag- num in the same localities. Hyalosphenia elegans, figs. 19-29, pi. XX, a common and graceful form, living among sphagnum, appears to be quite distinct from the pre- ceding species. The shell is compressed flask-shaped. Viewed on the broader side, the outline of the body is oval and more or less tapering into a rather long cyhndroid neck. The fundus is convex, and the oral end is sHghtly expanded and convex downward. In the view of the narrower side, the shell presents a long elliptical outline, tapering to the oral end, GEiniS HYALOSPHENIA— HYALOSPHEKLA ELEGANS. 141 which appears deeply notched from the turning upward laterally of the oral commissures. The shell is composed of transparent chitinoid membrane, of a pale chocolate-brownish hue, without a trace of definite structure. It is of uniform thickness, except that it forms a thicker border to the mouth. The sides" of the shell exhibit a more or less symmetrically corrugated appearance, due to series of hemispherical inflections, which are remarkably constant and persistent. The mouth is oval, and is convex in its wider diameter. The size and form of the shell vary but little. Commonly, specimens range from ^Igth to ^i^th of an inch in length, ^th to J-^th of an inch in breadth, and ^i^th to ^th of an inch thick, with the mouth j^th of an inch in the greater and g^th of an inch in the less diameter. The sarcode of H. elegans is colorless, though sometimes the endosarc appears more or less yellowish from the quantity of food it contains. Usually, the endosarc contains many vacuoles and food-balls, mostly of a yellowish or brownish hue, besides which it contains the usvial constituents found in allied forms. The nucleus is usually more or less obscured or may be completely hidden from view by the surrounding materials. It is pale granular and globular, and measures from ^^^ to j^th of an inch in diameter. From two to four contractile vesicles are frequently visible together in the vicinity of the nucleus at the periphery of the sarcode mass They measure about the ^^ of an inch previous to their collapse. The mass of sarcode occupies more or less of the interior space of the shell, according as the animal has been well or poorly supplied with nourish- ment. Sometimes it nearly fills the shell ; at others, it barely occupies half its capacity. Extensible threads of ectosarc diverge from the sarcode mass to the sides and fundus of the shell, varying in length in proportion as the mass enlarges or diminishes .^ The pseudopods are digitate, usually three or four in number, mostly simple, sometimes forking or branching, and finely granular in constitution. Specimens of H. elegans are frequently found with the sarcode in an encysted condition in the form of a compressed ovoid or spheroid ball, of variable size, as seen in figs. 27-29. These specimens also often exhibit a number of pale granular spheres, of variable size, occupying the neck of 142 FEESH-WATEE EHIZOPODS OF NOETH AMEBIC A, the shell, as represented in figs. 24, 29. They probably consist of excre- mentitious matters discharged from the sarcode ball as it assumed the resting condition. Sometimes specimens are met in which the position of the sarcode ball is occupied by a number of pale granular spheres, as represented in fig 25. They are of more uniform size and more definite granular structure than in the spheres of supposed excrementitrous matter. Their nature I have not determined, but have suspected them to be spores or reproductive bodies, though they may be entirely foreign to the rhizo- pod. They measure about the ^^^th of an inch in diameter. I have found no specimens referable to H. elegans which exhibited any clearly transitional disposition toward H. papilio or other forms. The thing previously described which appears most to resemble H. elegans is the Difflugia spirigera, of Ehrenberg, from the Bavarian Alps.* If what I have described as series of hemispherical inflections of the shell correspond with his four internal longitudinal spiral lines, the animals are probably the same, though the size he gives is a third less than the smallest of those I have observed. QUADRULA. Latin, quadrula, a little square. Difflugia: Wallich, 1863. AaauUna; HologlypTia: Ehrenberg, 1871. Quadrula: Schulze, 1875. Shell compressed pyriform, transparent, colorless, composed of thin square plates of chitinoid membrane, arranged in transverse or more or less obhque series, in consecutive or alternating order. Mouth inferior, termi- nal, oval. Sarcode colorless, having the characters of that of Difflugia, etc. QUADRULA SYMMETRICA. Plate XXIV, flgs. 20-25. Difflugia protdformis, Ya,T. symmetrica. Wallich: An. Mag. Nat. Hist, sii, 1863, 458, pi. x.fig. 16. mffiugia pgnformis, var. symmetrica. WaUioh : An. Mag. Nat. Hist, xii, 1863, 467 ; xiii, 1864, 232, pi. xvi, fig. 26. Difflugia symmetrica. Wallich : Ibidem, 245. Difflugia asaulata. Ehrenberg: Abh. Ak. Wis. Berlin, 1871,249, Taf. ii, Fig. 4,5. D. Asmlina assulata. Ehrenberg : Ibidem, 246. Difflugia carolinensis. Ehrenberg : Ibidem, 250, Taf. iii, Fig. 14. D. Assulina carolinensis. Ehrenberg : Ibidem, 246, 274. Difflugia Leptolepis. Ehrenberg : Ibidem, 254, Taf. iii, Fig. 15. D. AssuUna Leptolepis. Ehrenberg : Ibidem, 246, 274. Quadrula symmetrica. Schnlze: Arch. mik. Anat. 1875, 329, Taf. sviii. Fig. l-6.-Leidy: Pr. Ac. Nat. Sc. 1875, 415.— Archer : Quart. Jour. Mio. Sc. 1877, 122. *Monatsb. Berl. Ak. Wissens. 1853,526; Abhand. 1871, Taf. iii, Fig. 4. GENUS QUADEULA— QTJADEULA SYMMETEIOA. 143 Shell compressed pyriform : viewed on the broader sides, with the fundus widely convex, and the sides sloping or more or less inflected toward the oral end, which is convex downward ; viewed on the narrower side, ellipsoidal, with the fundus obtuse and the oral end roundly notched. Mouth transversely oval and convex downward. Shell colorless, trans- parent, composed of square plates arranged in transverse longitudinal or more or less oblique rows. Sarcode colorless ; pseudopods digitate, from one to three or more. Sise. — Length 0.08 mm. to 0.14 mm. ; breadth 0.04 mm. to 0.96 mm ; thickness 0.028 mm. to 0.048 mm. ; mouth from 0.02 mm. by 0.008 mm. to 0.032 mm. by 0.016 mm. Locality. — Dripping rocks with Fegatella, in Fairmount Park; ditch at the side of the Norristown railroad above Manayunk, Philadelphia; sphagnum of the sphagnous swamps of Absecom, Vineland, and other places in New Jersey. Quadrnla symmetrica, figs. 20-25, pi. XXIV, the only representa- tive of its genus, is remarkable for the peculiar construction of its shell, which is compressed pyriform. Viewed on the broader surfaces, the out- line is pyriform, or ovoid, with the sides sloping or more or less inflected, so as to produce a neck of variable length. The oral end is transversely convex. Viewed on the naiTower sides, the outline of the shell forms a long ellipse, tapering to the oral end, which appears notched. The mouth is transversely oval and entire. The shell is perfectly colorless and transparent, and is composed of square, structureless, chitinoid plates. These are arranged, with some gen- eral degree of regularity, in transverse, more or less oblique, or longitudi- nal rows. Longitudinally for the most part they successively increase in size from the vicinity of the mouth toward the fundus. Frequently the row surrounding the mouth is larger than the next, and those on the sum- mit of the fundus are smaller than the preceding ones. The general arrangement is like that of tiling with variable regularity. Mostly their order is consecutive, but sometimes somewhat alternating. They are not entirely disposed with the symmetry expressed b}^ their name, for frequently smaller plates break the regular succession of larger ones, and sometimes one angle of a plate replaces that of a contiguous one. 144 FEBSH-WATEE EHIZOPODS OP NOETH AMEEICA, Opposite sides of the same shell. Besides figs. 20-25, pi. XXIV, the accompanying figures, in the arrangement of the plates of the shell, represent the more important varieties which I have observed. The size of the shell ranges from about the 355th to the ith of an inch in length by ^^th to j^^th of an inch broad. The sarcode is colorless, and in all its characters resembles that of Hy alosphenia. The food- vacuoles often appear yellowish. The nu- cleus when visible measures about the Ti-„th of an inch or more. The pseudopods are digitate and usu- ally two or three in number. In several instances I have found specimens, late in the season, with the sarcode in a quiescent or encysted condition. Fig. 25 represents such a specimen obtained from sphagnum in November. It was of the largest size, about the j^th of an inch in length. The plates were arranged ob- liquely across the shell, and were pretty uniform in size. The neck was occupied by a laminated diaphragm as thick as one third the length of the shell. The sarcode mass formed a compressed oval ball occupying a cen- tral position in the body of the latter The ball was nearly colorless or faintly yellowish, and granular, and contained several large oil-like glob- ules. A central clearer space appeared to indicate the presence of a nucleus. Dead shells are sometimes found containing in the interior a number of scattered plates, or the same in one or more little packets, like those composing the wall of the shell. Quad/rula symmetrica was first described by Dr. Wallich, under the name of Difflugia symmetrica, from specimens found in England. It was more recently described, and referred to a new genus, by Prof. Schulze, from specimens found near Dresden. Ehrenberg described the same as pertaining to three different species, under the names oi Difflugia assulata, D. carolinensis, and D. leptolepis. These, in 1871, with a number of other forms, he referred to a subdivision of Dif&ugia with the names of AssuUna and HologlypM. A?, however, the GENUS NEBELA— NEBELA COLLAEIS. 145 latter would apply to the first members of the subdivision indicated, which appear to be only varieties or at most two species of Cyphoderia, neither of the names could be considered as properly taking precedence of Quadrula distinctly applied to Assulina assulata, the fourth member of Ehrenberg's list.* NEBELA. Greek, nebel, a bottle. Difflugia: Elirenberg, 1848. BeticelJa; Allodictya; Odonhdictya: Ehrenberg, 1871. Nebelcir: Leidy; 1874; Shell usually compressed pyriform, transparent, colorless, with or without appendages, composed of cancellated membrane or of peculiar intrinsic structural elements of variable form and size, mostly of circular or oval disks, of narrow rectangular plates or rods, or of thin, less regular, angular plates, often almost exclusively of one or the other, sometimes of two or more intermingled in variable proportions, sometimes of chitinoid membrane incorporated with more or less extrinsic elements, and sometimes of these entirely, as in DifSugia. Mouth inferior, terminal, oval. Sarcode colorless; in form, constitution, and arrangement as in Difflugia, Hyalo- sphenia, etc. NEBELA COLLARIS. Plates XXII; XXIII, figs. 1-7; XXIV, figs. 11, 12, Difflugia collaris. Ehrenberg: Monatab. Ak. Wis. Berlin, 1848, 218; Microgeologie, 1854, 331; Abh. Ak. Wis. Berlin, 1871, 143, Taf. ii. Fig. 27; Taf. iii, Fig. 21. Difflugia reticulata. Elirenberg: Monatsb. Ak. Wis. 1848, 218; Microg. 1854, 331; Ab. Ak. Wis. 1871, 143, JTaf. ii, Fig. 26. Difflugia cancellata. Ehrenberg : Monatsb. Ak. Wis. 1848, 379; Microg. 1854, 331; Ab. Ak. Wis. 1871, 145; Taf. ii. Fig. 3. Difflugia Carpio. Ehrenberg: Microg. 1854, 11&. D. Lagma p. Carpio. Elirenberg: Microg. 1854, 331; Abh. Ak. Wis. 1871, 251, Taf. ii, Fig. 22, 27. Difflugia binodis. Ehrenberg : Microg. 1854, 331 ; Abh. Ak. Wis. 250, Taf. ii. Fig. 22, 23. Difflugia annulata. Ehrenberg: Microg. 1854, — ; Ab. Ak. Wis. 1871, 249, Taf. iii, Fig. 19. Difflugia laxa. Ehrenberg: Microg, 1854, — ; Ab. Ak. Wis. 1871, 254, Taf. iii. Fig. 22. Difflugia peltigeracea. Carter: An. Mag. Nat. Hist, xiii, 1864, pi. i, fig. 12. Difflugia symmetrica. Wallich: An. Mag. Nat. Hist, xiii, 1864, pi. xvi, figs. 27-33. D. Beticella collaris (^Allodictya). Ehrenberg: Ab. Ak. Wis. 1871, 247. D. Beticella reticulata ( Odontodictya). Ehrenberg : Ibidem. D. Meticella cancrllata (Odontodictya). Ehrenberg: Ibidem. D. Beticella Carpio (Allodictya). Ehrenberg: Ibidem. D. Beticella binodis (Odontodictya). Ehrenberg: Ibidem. D. Beticella annulata (Allodictya). Ehrenberg: Ibidem. D. Beticella laxa (Allodictya). Ehreaberg: Ibidem. Difflmgia cellulifera. Ehrenberg : Deutsche Nordpolarfahrt, 1874, 460, 466, Taf. iii, Fig. 24. Difflugia (Nebela) numata. Leidy : Proc. Ac. Nat. Sc. 1874, 157. Nebela numata. Leidy: Proc. Ac. Nat. Sc. 1876, 116, figs. 1-5; 1877, 264. *Abhand. Akad. Wissens. Berlin, 1871, 246. 10 RHIZ 146 FEBSH- WATER KHIZOPODS OF NOETH AMERICA. Shell compressed pyriforra, longer than broad; in the broader view, with the fundus widely convex, the sides sloping downward and generally slightly inflected toward the oral end, which is convex downward; in the narrow view, oblong, with the fundus obtuse, sometimes impressed on each side, gradually sloping, and usually slightly inflected toward the oral end, which is notched Mouth transversely oval, entire. Shell colorless, exceedingly variable in its structural elements, generally composed of oval or circular disks, sometimes nearly exclusively of one or the other, or inter- mingled in various proportions, more or less uniform or variable in size, sometimes mingled with rod-like or narrow rectangular plates, and some- times almost wholly composed of these, rarely composed of thin, irregular, angular plates. Sarcode colorless, resembling in general constitution and arrangement that of Hyalosphenia, etc. ; pseudopods digitate, usually from three to half a dozen. Size. — In fifty specimens two thirds ranged between 0.1 mm. and 0.14 mm. in length. The smallest of the series was 0.064 mm. long, 0.036 mm. broad, 0.02 mm. thick, with the oral end 0.016 mm. broad and 0.008 mm. thick. The largest was 208 mm. long, 0.12 mm. broad, 0.06 mm. thick, with the oral end 0.048 mm. broad and 0.032 mm. thick. An average-sized specimen was 0.128 mm. long, 0.08 mm. broad, 048 mm. thick, with the mouth 0.032 mm broad and 0.024 mm. thick. Locality. — Moist sphagnum, of the sphagnous swamps of New Jersey, Pennsylvania, Maine, Florida, Alabama; rarely in moss at the edge of a pond in the Uinta Mountains, Wyoming Territory. ]\ebela collaris (pi. XXII; pi. XXIII, figs. 1-7), a remarkable and beautiful rhizopod, is common and abundant, living in the moist sphag- num of the sphagnous swamps of New Jersey and Pennsylvania. It is a constant associate of Hyalosphenia papilio and H. elegans Sometimes the spha,gnum in certain localities actually swarms with the animal, and a drop of water squeezed from the plant contains a multitude of them. At other times and in other localities, apparently under equally favorable circumstances, the sphagnum contains few or none of the animals, though it is rare not to find traces, such as a few dead shells, in the sphagnum of most localities. The shell is compressed pyriform, longer than broad, though varying GENUS NEBELA— NEBELA COLLAEIS. 147 considerably in the proportion of the different measurements. Viewed on the broad surface, the outline is pyrifonn, with the oral end convex down- ward. The sides slope downward to the mouth, sometimes nearly in a straight line, sometimes with more or less inflection, giving rise to a neck of variable length, though generally short. In the view of the narrower surface, the outline is elliptical or more or less narrowly pyriform, with the oral end concavely notched, and with the fundus obtuse, and sometimes impressed at the sides. The transverse section of the shell is oval and evenly rounded at the poles, but occasionally is narrowed gradually, or somewhat abruptly approaching the latter. In some specimens, the section has a hexahedral outline, with concave sides and prominent rounded angles, as seen in fig. 6, pi. XXIII. Sometimes the shell is impressed laterally and at the fundus, so as to produce obtusely angular borders and a somewhat carinated appearance, as seen in fig. 4, pi. XXII, representing a transverse section. Sometimes the narrower forms present at the lower third, at each lateral border, a slight conical prominence, at the apex of which the shell appears to be perforated by a minute pore, as seen in figs. 1, 2, 4, 7, pi XXIII. The mouth is transversely oval and entire, and has rounded com- missures, as seen in fig. 4, pi. XXII. In composition, the shell is of extraordinary character, from the variety in form and arrangement of its elements. Most frequently it is composed of oval pr circular disks, as represented in figs. 1-12, 15-17. The disks usually hold no relationship in size with that of the shell : the smallest specimens may have the largest disks, and the largest ones may be com- posed of those of the smallest size. Sometimes the shell is almost entirely composed of circular disks, sometimes of oval disks, and frequently the two kinds are intermingled. Sometimes they are of pretty uniform size ; at others, they are intermingled, of different sizes. Most frequently the larger disks occupy the fundus and body and the smaller ones the lower part or neck of the shell. Sometimes the larger disks are more or less scat- tered, with some approach to uniformity, and the intervals are occupied by smaller ones. Indeed, there exists almost any conceivable arrangement of the round and oval disks in the construction of the shell. Another variety of the shell, not uncommon, though less frequent than 148 FEESH-WATER EHIZOPODS OF NORTH AMERICA. the former, is composed of narrow rectangular plates, intermingled with a comparatively few round or oval disks, as seen in figs. 13, 18, pi. XXII. The narrow plates are usually placed parallel, in close juxtaposition, in small patches, which are arranged in different directions, while the round or oval plates occupy intervals here and there, singly or two or three together. The general appearance gives the impression of certain kinds of tessellated pavement. Some shells are mainly composed of round and oval disks, of the variety first described, intermingled with a few narrow rectangular plates or rods, of various lengths, as represented in fig. 7. Occasionally I have seen specimens with extraneous matters, such as quartz particles and diatoms, incorporated with the shell. A specimen represented in fig. 8 appears to have a few sponge spicules added to the ordinary intrinsic elements of composition. Not unfrequently there are found, in association with the usual more characteristic varieties of Nebela coUaris, Individuals which have the same form of shell, but with its structure rather related with that of the ordinary forms of Difflugia. In some specimens the shell is composed of thin and irregularly angular silicious plates, as represented in fig. 12, pi. XXIV. The intervals of the plates appear as dark or clear outlines, according to the focus, and the margin of the mouth of the shell is uneven, as it is formed by the bordering plates. Mostly the intervals of the silicious plates are conspicuous, and appear to be occupied by a clear cementing substance, or the shell appears to be composed of clear chitinoid membrane paved with the silicious plates, as seen in fig. 11. The specimens vary greatly in the forms of the component silicious plates, which consist of variable proportions of the kind just described, with others which are more regularly rectangular, or in the form of rods, and sometimes with diatoms, and round or oval plates like those which ordinarily compose the shell oi Nebela collaris. Through such specimens the latter would appear by transition forms to merge into Difflugia compressa. The sarcode of Nebela collaris is colorless, but frequently the endosarc appears more or less yellowish or brown, from the abundance of mingled food in balls and as diffused granular matter. It is a remarkable fact that rarely green food or food of any other color than those just mentioned is seen in this animal. GENUS NBBELA— NEBELA OOLLAEIS. 149 The general appearance, extent, arrangement, and constituents of the sarcode are the same as in Hyalosphenia. The nucleus is usually obscured from view by the accumulation of food and other matters. The contractile vesicles are seen, two or three in number, between the position of the nucleus and the periphery of the sarcode mass. Among the yellowish contents of the endosarc, the balls often have the appearance of oleaginous globules The pseudopods are digitate, mostly simple, and usually from two or three to half a dozen in number. They extend to the gj^th of an inch in length or more, and commonly are about the g-jj^oth of an inch thick. The range of size and the proportionate diameters of Nehela coUaris vary considerably. Average-sized specimens are about ^Jotli of an inch long, gjgth broad, ith thick, with the mouth about jji^th broad and ji-^th in the short diameter. A common-sized specimen was the ^th of an inch long, ith broad, g^ith thick, with the oral end gij^tli by —^th of an inch. The smallest specimen, of a large number, was gi^th of an inch long, ith of an inch broad, ^.^^th of an inch thick, with the mouth end jijth by gigth of an inch. The largest specimen, from moss, on the borders of a lake high up in the Uinta Mountains, Wyoming Territory, was j^th of an inch long, jigth of an inch broad, and jith of an inch thick, with the oral end ith by ^g^th of an inch. Nehela coUaris may frequently be observed with the sarcode in the condition of a quiescent ball, or in an encysted state, occupying the central portion of the body of the shell, as represented in figs. 7, 8, 1 0, pi. XXII. The ball is compressed spherical, and varies in size in diiferent individuals. At an early stage it contains a qxxantity of the yellowish food, but this is gradually discharged, and contributes to the formation of the epiphragm usually found occupying the mouth and neck of the shell. In its later condition, the sarcode ball is pale yellowish or nearly colorless, of granular constitution, mingled with coarser and mOre defined granules and oleagi- nous-looking globules, small and large. The epiphragm (fig. 7). is laminated, and often contains globulai- bodies, apparently remains of the food discharged or purged from the sarcode ball. Occasionally specimens occur in which the sarcode is substituted by a variable number of granular spheres, of nearly uniform size, which. 150 FEESH-WATER EHIZOPODS OP NORTH AMERICA. as in other similar cases, I have suspected to be spores or reproductive germs; though they may not belong to the animal, and may be of parasitic nature. Nehela collaris was originally described by me under the name of Nehela numata; but on studying the Hterature relating to the Fresh-water Rhizo- pods, I have been led to the conclusion that the same had been repeatedly described by Ehrenberg with different names, of which Difflugia collaris is one of the earliest. All the forms described and figured by Ehrenberg with the names of Difflugia collaris, D. reticulata, D. cancellata, D. Carpio, B. hinodis, I), annulata, B. laxa, and D. cellulifera, I suspect to pertain to the same animal, and this I suppose to be the same as that I first described as Nehela numata. In a systematic arrangement of the Arcellinse,* Ehrenberg has placed the above-named forms, except the last one, in a group he calls Difflugia Beticella. Of this he makes an edentate suhgromp,—Allodictya, and a dentate group, — Odontodictya. If the names of Beticella, Allodictya, and Odontodictya are to be regarded of generic or subgeneric value, they would apply to the first-named species of the group or subgroups. D. Beticella asterophora is the first species of the first subgroup, and D. Beticella binodis that of the second subgroup. The character of the former -is obscure; but, judging from the imperfect figure, it is not generically the same as Nehela, and therefore the names of Beticella and Allodictya would hot supplant Nehela. Nor would Odontodictya correctly replace Nehela; for, although Difflugia hinodis with little doubt refers to what I have considered a variety of Nehela collaris, the term is erroneous, for no species of Nebela iS'dentated. I think it probable that several other forms described and named by Ehrenberg likewise pertain to Nehela collaris, but they are so doubtful that I think it unnecessary to mention them. The series of specimens represented by Dr. Wallich in figs. 27 to 33, pi. XVI, of the thirteenth volume of the Annals and Magazine of Natural History for 1864, and described as transition forms of Difflugia symmetrica, appear to me to pertain to the same animal as Nehela collaris. Dr. Wallich remarks that the shell is sometimes compressed, but frequently is not so. *Abhand. Akad. Wissens. Berlin, 1871, 244. GENUS NEBELA— NEBELA COLLAEIS. 151 In all other respects, the forms agree with the varieties of N. collaris, hut I have never met with specimens in which the shell was otherwise than com- pressed. Mr. Carter, in the same work, described a form under the name of Difflugia peltigeracea, which probably also belongs to the same animal as Nebela collaris. The nature of the singularly varied shell of Nebela collaris I have not been able to determine with any satisfaction. In the characteristic forms, the elements of structure, the disks and plates, appear to be intrinsic, and not of a foreign character. • They appear to be cemented together or conjoined at the borders, and not implanted upon or incorporated with a distinct chitinoid membrane. In breaking the shell, the line of rupture follows the outlines or intervals of the disks and plates. The shell appears to be silicious, as it remains unchanged when exposed to the action of heated sulphuric and nitric acids. Dr. Wallich, in referring to the structure of the shell of the transitional forms of Difflugia symmetrica, which, as previously intimated, I suspect to belong to Nebela collaris, calls the peculiar elements colloid disks and plates. He remarks of them that they are derived from the animal, and not directly from the medium in which it lives. He supposes, however, that they are formed through the coalescence of diatoms and other mineral elements with the chitinoid basal substance of the shell, which then undergo metamorphosis into all the colloid forms that occur.* Of this process I have been unable to satisfy myself; but the exceed- ingly varied specimens which have come under my notice, of shells composed of elements appar- ently intrinsic and of regular but widely different forms, of others apparently of extrinsic elements regular and irregular, with many others of a transi- tional character, would appear to justify the con- clusion of Dr. Wallich. Since the foregoing went to press, in sphag- num from the cedar swamp of Malaga, Gloucester County, New Jersey, among multitudes of characteristic specimens of Nebela collaris, together "Annals and Mag. of Nat. Hist. 1864, xviii, p. 234, pi. ivi, figs. 27-33. Curved variety of Nebela collaris. 152 FEESH-WATEE EHIZOPODS OF NOETH AMEEICA. with many other rhizopods, I observed o*«.^ Arobe.: P^^^^^^^^^^ Micr. Club, 1875, 'in ^uart.'joi,;. Mic. Sc. 1876, 107,- Ibidem, Muglypha seminulum. Leidy : Pr. Ac. Nat. Sc. 1878 172. Shell nearly as broad as long, compressed oval, brown in color; borders obtuse, spineless; plates hexagonal or oval; mouth transversely oval, with the margin lacerated or irregularly notched Sise— From 0.U44 mm. long by 0.36 mm. broad and 0.016 mm. thick to 0.08 mm. long by 0.072 mm broad and 0.032 mm. thick. Locality. — Common in sphagnous swamps. In AsfsuJina seminulum the shell is compressed spheroidal or oval, with the breadth nearly equal to the length, and the thickness about half, or less than half the breadth. The dome and lateral borders are rounded or at most sub-acute. The mouth is transversely oval, and abruptly truncates the pole of the shell, or the latter may be slightly prolonged so as to form a short neck. The shell is chocolate-brown in color, of variable shade, sometimes quite light, and in very young individuals colorless, in old ones sometimes very dark At the. mouth it usually presents a lighter band of color. See figs. 16-27, pi. XXX VII. The shell is composed of minute oval or hexagonal plates arranged in alternating longitudinal series or obliquely parallel spiral rows. The oral plates, hghter colored and thinner than the others, end in irregular processes, which give to the border of the mouth a lacerated appearance. The soft part of Assulina seminulum has the same constitution as in the species of Euglypha. Usually, I have found it to occupy but little more than half the capacity of the shell, as seen in figs. 18, 19. The animal seems to be exceedingly shy or sensitive, and usually after disturbance remains quiescent for a very long time. The pseudopods are few and extremely delicate. *The original description of Difflugia Seminulum, by Ehrenberg, in the 'Monatsberichte,' is as follows: "Lorica brevius ovata, fusca, superficie anguste et subtiliter areolata simplici, ostiolo lato, 15 BHIZ 226 FEESH-WATER EHIZOPODS OP NOETH AMEEIOA. The size of the shell ordinarily ranges from 0.05 mm. to 0.08i5 mm. long, 0.04 mm. to 0.071 mm. broad, and 0.0161 mm. to 0.033 mm. thick. Assulina seminulum is common in sphagnum, and is often one of the most abundant forms. It is remarkable that among the specimens com- monly observed comparatively few are living. The same observation has been made by Mr. Archer, who recently, as 1, described the species as a new one of Euglypha. TEINEMA. Greek, tri, three; nema, thread.* Animal provided with a hyaline, pouch-like shell, with its long axis incHned or oblique, and with the mouth subterminal. Dome obtusely rounded; mouth inverted, circular, minutely beaded at the border. Struc- ture of the shell in the smallest forms mostly appearing homogeneous, but in the larger composed of circular plates arranged in alternating series, and often appearing with a beaded margin. Sarcode and pseudopods as in Euglypha. Animal when in movement with the body inclined, the mouth being anterior and downward; the fundus directed upward and backward. TRINEMA ENCHELYS. Plate yyiTTY . Trinhne. Dujardin: An. So. Nat. 1836, v, 198, 205, pi. is, fig. Ao-A^. Difflugia Enchelya. Ehrenberg : Infusionsthierchen, 1838, 132, Taf. ix, Fig. iv.— Pritchaxd : Hist. Infusoria, 1861, 553, pi. xxi, fig. 19. Trinema. Dujardin : An. So. Nat. 1838, x, 261, note to 263.t AreelU hyalina. Ehrenberg: Abh. At. Wis. 1841, Taf. i, ii, Fig. 31, Taf. iii, vi, Fig. 6, Taf. iv, 1, Fig. 34, a, T>, T.Flg. 3; 1856, Tafel (p. 377), Fig. 2, 3. Monatsberichte, 1848, 215; 1849, 98. Trinema acinus. Dujardin: Infuaoires, 1841, 249, pi. iv, fig. 1.— Perty: Kennt. kleinst. Lebensformen, 1852, 187.— Freseniua: Abh. Senok. Naturf. Gesell. 1856-8, 223, Taf xii. Fig. 25-27.— Clapa- rfede and Lachmann: Infus. et Ehizopodes, 1858-9, 455.— Leidy : Pr. Ac. Nat. So. 1874, 227; 1877, 321.— Schulze: Aroh. mik. Anat. 1875, 104, Taf v. Fig. 9-11. Arcella comtricta. Ehrenberg : Abh. Ak. Wis. 1841, 410, Taf iv, i. Fig. 35. Mikrogeologie, 1854, Taf xxxix, iii, Fig. 3. Arcella Nidus Pendulus. Ehrenberg : Abh. Ak. Wis. 1841, 410, Taf iii, i. Fig. 48. Arcella Vkpliara. Ehrenberg : Abh. Ak. Wis. 1841, 410, Taf iv, ii. Fig. 12. Arcella caudicicola Ehrenberg: Monatsb. 1848, 215, 218. Abh. Ak. Wis. 1871, Taf. u. Fig. 31. Arcella Encliehjs. Ehrenberg : Mikrogeologie, 1854, Taf xxxviii, Fig. 5, Taf xxxix, iii. Fig. 4. Monatsb. 1845, 319; 1848, 215; 1849, 299; 1851, 228; 1853, 182, 266, 332; 1854, 710; 1856, 337, (Tafel; Fig. 2. * Named from the circumstance that commonly three pseudopodal threads are observed projected from the mouth of the shell. tin 1838, Dujardin employed only the gallicized name of Trinhne for the little rhizopod; and not until 1838, after the publication of Ehrenberg's ' Infusionsthierchen,' did he use the name Trinema. In the note indicated he speaks of Ehrenberg's Difflugia Mnchelys as clearly being the same as his Trmema. Not until 1841, in his ' Histoire des Infusoires,' does he give to it the specific name of T. acinus. GENUS TEINEMA— TEINEMA ENGHELTS. 227 Ayrella Megastema. Ehrenberg. Monatsb. Ak. Wis. 1853, 182; 1856, 337, (Tafel) Fig. 3 Miiroeeoloeie 1854, Taf. xsxiv, viii, Fig. 1. Abb. Ak. Wis. 1871, 259. s s , Euglyphaplmrostoma. Carter: An. Mag. Nat. Hist. 1857, xx, 35, pi. i figs 19 a^ liuglypha Enchehja. WaUicli : An. Mag. Nat. Hist. 1864, xiii, 245, pi. xvi, fl-s 46 47 Arcella roairata. Ehrenberg : Abb. Ak. Wis. 1871, 272, Taf. iii, ii. Fig. 2. ' Aroella reticulata. Ehrenberg : Ibidem, Fig. 5. Arcella seriata. Ehrenberg : Ibidem, Fig. 6. Arcella Pyrum. Ehrenberg : Ibidem, Fig. 15. Eomwochlamya^conaMcta, B. DiaphcBra, H. Enchehja, S. hyalina, and S. roatrata. Ehrenberg: Abh. Ak. Sticholepia caudicicola, S. Nidua Pmdulus, and S. Megastoma. Ehrenberg: Ibidem Heterocoamia Pyrum. Ehrenberg : Ibidem, 245. Trine/ma mchelya. Leidy: Pr. Ac. Nat. So. 1878, 172. The only species of the genus. Sise.~Rangmg from 0.016 mm to 0.1 mm. long by 0.01 mm. to 0.06 mm. broad, and mouth from 0.005 mm. to 0.024 mm. in diameter.* Locality.— BTphagnous swamps, wet forests about the roots of mosses, in marshes, and in the ooze of pools and ponds. Trinema enchelys is one of the commonest and smallest of the shell- bearing rhizopods, and is found almost everywhere in moist places as well as in pools and ponds. It is especially abundant in sphagnous swamps, but is often found in the earth about the roots of mosses and other plants, even in such places as roadsides, on the bark of trees, old wooden or thatched roofs, and in the crevices of pavements of cities. It was originally described by Dujardin under the name of " Trinfeme," and it was not until after the publication of Ehrenberg's 'Infusionsthierchen,' in which it is described and figured as Difflugia EncMys, that the former called it Trinema acinus. Though the latter name is employed by most subsequent writers, according to the rules of zoolbgical nomenclature the one I have adopted at the head of this chapter is the proper one. Trinema enchelys is very variable in form and size, and thus helped Ehrenberg to swell the long Hst of his Difflugias and Arcellas. See pi. XXXIX. The shell is colorless, transparent and pouch-like, with the oral end usually the smaller. The mouth opens downward beneath the oral extremity, and the inflated fundus of the shell is directed obliquely back- ward and upward. In the full view of the shell, beneath, its outline is usually more or less * The measurements are taken from the view of the shell beneath, giving the extreme length from the edge of the shell in advance of the mouth to the summit of the fundus, while the breadth indicated applies to the latter. 228 PEESH-WATER EHIZOPODS OF NOETH AMERICA. pyriform reversed, but it is sometimes oval, ovoid, oblong, or more or less constricted nearly on a line with the back part of the mouth. Sometimes the oral extremity appears broader than the fundus, which is obtusely rounded. The mouth is circular, and has a crenulate or beaded border. In the side view of the shell, in the position in which it is maintained when the animal is in movement, the fundus is variably elevated. Some- times the oral side of the shell is on the same plane as the mouth, and the fundus is directed backward. In other specimens, the longitudinal axis from the mouth to the fundus exhibits various degrees of inclination. The oral end of the shell beneath is concave, or the mouth appears inverted, forming the inner orifice of a shallow funnel. In many specimens of Trinema enclielys, especially in small and per- haps young ones, the shell appears to be composed of clear homogeneous membrane. In many others, especially large individuals, the shell is com- posed of circular plates with beaded borders, conjoined by an intervening amorphous cement, as represented in figs. 1-4. In some specimens, as seen in figs. 28, 29, the circular plates appear to overlap in the same manner as in species of Euglj^pha. In many specimens of Trinema, especially those of intermediate and of the larger size, in which the shell appears to be homogeneous, the out- lines exhibit a more or less undulating character, apparently indicative of a constitution of disks, though these are not perceptible. The interior soft structure of Trinema is identical with that of Euglypha. Usually, two contractile vesicles are observable at the sides of the nucleus, even in the smallest individuals. The pseudopods are likewise of the same kind as those of Euglypha. Three are commonly seen, whence the name of the genus ; but the number is by no means definitely restricted, and there may be one to half a dozen or more. The size of Trinema presents a wide range The smallest one meas- ured was 0.0161 mm. long by 0.01 mm. bl'oad, with the mouth 0.005 mm. wide. The largest was 0.1 mm. long and 0.062.'') mm. broad, with the mouth 0.0238 mm. wide. Between these extremes I have observed all gradations of size. As mentioned at the beginning of the present chapter, Trinema is one of the most common of the Fresh-water Rhizopods, being found in almost all positions in which other forms exist. A small form appears to be a pretty GENUS SPHENODEEIA— SPHENODEEIA LENTA. 229 constant associate of the common rotifer among mosses and other plants in damp, shaded places. I find it abundantly, all the year round, in the crevices of the brick pavement, in front of my house, about the roots of the little pearlwort, Sagina apetala. This small form appears to have a homogeneous shell, and is about 0.0238 mm. long by 0.02 mm. broad. In dry weather, like the rotifer,. it becomes quiescent, but during and after rain it assumes the active condition. SPHENODERIA. Greek, sphen, a wedge; dm-a, the neck.* Shell globular or oval, sometimes slightly compressed, hj^aline, mem- branous, with a short, broad neck, and a wide elliptical, subterminal, or oblique (?) mouth. Body of the shell with circular, oval, or hexagonal cancelli or plates arranged in alternating series. Sarcode and pseudopods as in Euglypha. SPHENODERIA LENTA. Plate XXXIV, figs. 25-41. Sphenoderia Utita. Schlumljerger : An. So. Nat. 1845,256.— Ehreuberg: Abli. Ak. Wis. Berlin, 1871, 236. Euglypha globosa. Carter : An. Mag. Nat. Hist. 186.5, xv, 290, pi. xii, fig. 14.— Hertwig and Leaser : Arcli. mik. Anat. 1874, x, Snppl. 129, Taf. iii. Fig. 7.— Sohulze : Ibidem, 1875, 102, Taf. v, Fig. 5, 6.— Leidy : Pr. Ac. Nat. Sc. 1874,226; 1878,172. Difflugia Imta. Ebrenberg: Abh. Ak. Wis. Berlin, 1871, 246. Assttlina lenta. Ehrenberg : Ibidem. Animal comparatively small. Shell delicate, membranous, colorless, transparent, globular, oval or oblong, of uniform transverse diameter or sometimes slightly compressed, with a short, broad, compressed neck, widening toward the narrow elliptical mouth, which is oblique or subter- minal (?) . Border of the mouth thin, delicate, entire. Body of the shell com'posed of circular or oval plates overlapping at their contiguous borders and arranged in alternating series, and apparently not extending into the neck. Sarcode as in Euglypha and Trinema. Si^e.—rGrlohose forms from 0.032 mm. long by ('.028 mm. broad to 0.056 nmi. long by 052 mm. broad or to 0.056 mm. in diameter ; oval forms from 0.028 mm. long by 0.02 mm. broad to 0.056 mm. long by 0.044 mm. broad. Locality. — Common in moist sphagnum in the cedar and other bogs of New Jersey, Pennsylvania, Alabama, and Florida ; also in swampy locaK- ties at Fort Bridger, Wyoming Territory. * Agassiz : Nomcnclator Zoologicus, has deros, the skin ; but this I infer to be a mistake. 230 FEESH-WATEE EHIZOPODS OP NOETH AMEEICA. Sphemderia lenta is the subject of one of the descriptions of certain species and genera of Rhizopods, by Schlumberger, in the 'Annales des Sciences Naturelles' for 1845. The descriptions, being brief and unac- companied by illustrations, have given rise to differences of opinion as to what particular forms they apply. The genus Sphenoderia is described as possessing "a diaphanous, globular shell, orpamented with polygonal im- pressions in regular oblique series, and having a broad, and short wedge- shaped neck, with the terminal aperture almost linear." The pseudopods are filiform, long and fine. The foiTu of the neck and of the aperture separates the genus from Trinema and Euglypha, to which it is related in the structure of the shell. Later, Mr. Carter described a rhizopod, under the name of JSuglypha glohosa, with a globular shell having a short, compressed, wedge-shaped neck, which has appeared to me to be the same thing. Schuize remarks that the MuglypM glohosa is probably the same as Sphenoderia, but considers it uncertain for want of figures of the latter for comparison.* Sphenoderia lenta, which I regard the same as Euglypha glohosa, is common in the wet sphagnum of spha^nous swamps, and is also less frequently to be found about the roots of Selaginella, Hypnum, and other mosses and plants in bogs. It is a comparatively minute creature, like Trinema, and is also a shy animal, little disposed to movement when disturbed. The shell has the form of an oval or spherical sac, or less frequently is oblong oval, and is provided with a short neck. The body is usually of uniform transverse diameter, but is sometimes more or less compressed. The fundus is obtusely rounded and devoid of appendages. See figs. 25— 41, pi. XXXIV. Like other investigators, I have been puzzled to ascertain the exact char- acters of the neck and mouth of the shell. In the ordinary view, the n«ck has appeared to me to be short, wide, and saucer-shaped, with an elliptical mouth. In the opposite direction it appears as a conical point, whence no doubt the name of the genus Sphenoderia, signifying wedge-like neck. In viewing the shell in an intermediate position, by causing it to turn on its axis, the neck appears as a pair of conical points, with the border of the mouth festooned between them. I have supposed the mouth to be elliptical * AroMv f. mikroskopische Anatomic, 1875, 104. GENUS SPHENODEEIA— SPHENODERIA LENTA. 231 and oblique or subterminal, so that in the narrow angular view of the neck it is directed toward one of the wider sides. Hertwig and Lesser, in the same animal, under the name of Euglypha gloiosa, describe the neck as consisting of a pair of lateral points, between which the edges of the mouth are cut out concavely.* The body of the shell of SpJienoderia lenta has appeared to me to be composed of circular or oval plates, arranged in alternating rows, and over- lapping at the contiguous borders, so as to give the impression of hexahe- dral areas included within circles of minute elliptical areas, as represented in figs. 25, 26, 41, pi. XXXIV. Hertwig and Lesser describe the plates as hexagonal, with minute, intervening, transverse, elliptical, more prominent plates.f In some instances, the plates have appeared to me to be definitely hexahedral, aifd closely adapted to one another without accessory plates, as in the variety represented in fig. 34. The neck of the shell, between its lateral angular points, is thinner than any other part, and consists of delicate homogeneous membrane, extending beyond the plates of the body to the border of the mouth. The latter is entire, but I have occasionally met with empty shells, in_ which the border was divided into several lobes, perhaps the result of laceration, as seen in fig. 34. In repeated instances I have found individuals of Sphenoderia, with an oblong oval shell, having the border of the mouth divided into a num- ber of minute points, as represented in fig. 40. Sometimes the points appear of an irregular character, as in Assulina seminulum. I have met with several individuals of Sphenoderia, in which the shell was ovoid, with the narrow pole terminated by the mouth, which had a minutely denticulated border. The body of the shell was composed of accurately adapted plates of hexagonal form and uniform size. In the specimens previously indicated, fig. 40,^ the plates of the shell were circular and overlapping. The interior soft structure of Sphenoderia, and its pseudopods, are identical in character with those of Trinema and Euglypha. Sphenoderia nearly related with Trinema, and the variety having a denticulated mouth is also nearly related with Assulina seminulum. * ArchiY f. mikros. Auatomio, 1874, x, Suppl. 130. tibiikni, l:n. 232 FEESH-WATBE EHIZOPODS OF NORTH AMEEICA. Globular forms of Sphenocleria lenta range from 0.033 mm. to 0.055 mm. in diameter ; oval forms from 0.0285 mm. to 0.0625 mm. long by 0.02 mm, to 0.0454 mm broad. SPHENODERIA MACROLEPIS.' Shell pyriform, compressed, with a broad neck gradually extending from the body, and terminating in the oblique elliptical mouth, and with the broader surfaces, composed mainly by a pair of large hexahedral plates, from which the neck is extended below. Size. — From 0.02 mm. to 0.028 mm in length. Locality. — Sphagnum of the cedar swamps of New Jersey. Not until a comparatively recent date, and since the present work was going through the press, I have discovered what appears to be a second and quite distinct species of Sphenoderia. It was found in association with S. lenta, in sphagnum of several localities in New Jersey, but especially in that of the cedar swamp at Malaga, Gloucester County. It is probably not uncom- mon, but may be easily overlooked, for it differs little in size and form from 8. lenta, and the peculiar structure of the shell in the living animal is obscured by the presence of the sarcode. The shell is moderately compressed pyriform, and varies little in shape or size. It usually measures 0.024 mm. in length by 0.016 mm. in the greater and 0.012 mm. in the less breadth. The neck tapers from the body of the shell, but in other respects appears to have the same characters as in 8. lenta, and in the narrower side view of the shell it presents the wedge-like outline characteristic of the genus. The delicate colorless shell when empty distinctly exhibits, on the broader sides of the body, a pair of large hexahedral plates, one above the other, as represented in the adjoining woodcut. Another less distinct plate occupies the fundus above the preceding, and a pair of smaller lozenge- like plates apparently occupy the intervals laterally of the two pairs of broad hexagonal plates. The Shell otsphenodma macroUpis. neck is prolonged below the position of the body- plates, and appears to be devoid of distinct or separate plates. The interior sarcode of 8. macrolepis is identical in character with thai, of 8. lenta. HELIOZOA. Greek, Iwlios, tlie sun ; zoon, animal. While the Lobose a,nd Filose Protoplasts are essentially creeping ani- mals, and in all the shell-covered forms habitually move about with the mouth of the shell downward, and with the pseudopods spreading therefrom in contact with the surface on which they move, the-HeliozOans or Sun- animalcules are swimmers. Their body is commonly of spherical form, and delicate pseudopodal filaments radiate from every part of its surface. While some are naked or entirely soft, others are provided with a sort of protective skeleton, consisting of radiant spines, of minute spicules imbedded in an exterior protoplasmic layer, or of a delicate latticed shell. The soft spheroidal protoplasmic body, in general, exhibits the same essential constitution as in the Protoplasts, and commonly presents but little more distinction of ectosarc and endosarc than in the Filosa. A large proportion of clear globules or vacuoles form a common constituent, giving to the body a foamy appearance, not usual in any of the Protoplasts. Generally, the body contains a single central nucleus ; but, in a few forms, a number of nuclei occur scattered through the mass. In some of the Heliozoans, one or more conspicuous contractile vesi- cles appear on the surface of the body, and exhibit the usual phehomena as indicated in the description of the Protoplasts. As the contractile vesicles enlarge, they rise prominently above the surface of the body, and appear like floating bubbles. In their abrupt collapse and discharge of the con- tents, they often give rise to a visible shock to the body of the animal. In other Heliozoans, if contractile vesicles occur, they have escaped detection. Some Heliozoans appear bright green from the presence of chlorophyl in variable proportion, as one of the constituents of the body. The pseudopodal rays are in the form of delicate threads of granular protoplasm, emanating from all parts of the body. , They are commonly simple filaments, rising by a broad base, rapidly tapering to extreme fineness and variable length, often exceeding the diameter of the body. They •2'M 234 FEESH-WATEE EHIZOPODS OF NOETH AMBEICA. rarely fork or branch at the ends, and even more rarely anastomose. In some forms, on the coarser rays, a slow circulation of granules may be detected, proceeding outwardly and inwardly. The pseudopodalrays are commonly very numerous, but are variable in number in the same as well as in different Heliozoans. They usually appear perfectly straight and rigid, but are highly flexible and contractile. The contact of a roving animalcule of some strength will cause them to bend like the hairs of a brush under similar pressure. In one form of the Heliozoans, the Actinospheerium, the pseudopodal rays are sustained by a more consistent axial thread, springing from among the superficial layer of vacuolar corpuscles of the body. The pseudopodal rays are the organs of locomotion and prehension of the Heliozoans. By their means the animals swim in a slow even manner through the water. Food particles, plant or animal, coming into contact with the rays, adhere, and are drawn by their contraction to the body. When the latter is reached, usually a quantity of clear protoplasm is pro- jected or exudes and envelopes the food, which is then gradually drawn into the body of the animal through the contraction of the exuded proto- plasm. Heliozoans commonly multiply by division, as may be frequently seen with the common Sun-animalcule, Actinophrys sol. The Heliozoans bear a close resemblance to the marine Radiolarians, and have hence been called Fresh- water Radiolarians; they are, however, of much simpler constitution, and are justly considered by most authorities as forming a distinct order of Rhizopods. AOTINOPHEYS. Greek, alcHn, a ray ; o^lirus, tlie eyebrow. Body soft, spherical, composed of a hyaline, colorless, pale, and finely gi'anular protoplasm, with mingled coarser granules and minute oil-like molecules, and more or less crowded with large clear vesicles or vacuoles. Nucleus central, ordinarily obscured from view by the vesicular structure of the sarcode. A large contractile vesicle at the periphery. Pseudopods numerous, projecting as exceedingly delicate tapering rays, or filamentous, finely granular extensions of the protoplasm of the surface of the body, not branching. GENUS ACTINOPHEYS— ACTIIsrOPHEYS SOL. 235 ACTINOPHRYS SOL: Plate XL. " Un poisson des plus extraordinaire que Von en puisse voir." Joblot: Obs. Hist. Kat. i, 1754, 64 pi. 7 fig. 15. Ti-icTioda Sol. Miiller: Verm. Terrest. Fluv. 1773,76. Anim. Infus. 1786,164, tab. xxiii, figs. 13-15.— Schrank: Fauna Boioa, iii, 2, 1803, 93. Peritrxdha Sol. Bory: Encycl. M^tb., Vers. 1824. Aelinoplmja Sol. Ebrenberg : Abb. Ak. Wis. Berlin, 1830, 42, 53, 61, 76, Taf. ii. Fig. 4 ; 1831, 102. Infusions- tbieroben, 1838, 303, Taf. xxxi, Fig. vi.— Dnjardin: Infusoires, 1841, 262, pi. iii, fig. 3.— Party : Kennt. tleinst. Lebensformen, 1852, 159.— Stein: Infusiontbieie, 1854, 151— Clapa- rfede and Lachtnann: Etudes Infusoires, i, 1858-59, 450.— Pritohard : Hist. Infns. 1861,559, pi. xxiii, figs. 28, 31, 32.— Wallicb : An. Mag. Nat. Hist. 1863, xi, 446, pi. x.fig. 4.— Cien- kowsM: Arch. mik. Anat. i, 1865, 227.— Grenacber : Verb, pbys.-med. Gesells. Wiirzb. i, 1868, 170, Taf iu.— Hertwig and Lesser: Arob. mik. Anat. x, 1874, 164, Taf. v. Fig. 2.— Mi- crographic Dictionary, pi. 23, fig. 7 6. — ^Leidy : Pr. Ac. Nat. Sc. 1874, 23. Actinophrys difformis. Ebrenberg : Abb. Ak. Wis. Berlin, 1831, 102. Infusionstbiercben, 1838, 304, Taf. xxxi. Fig. 8. Aeiinop'hrys Eichhornii. Claparfede: Miiller's Arcbiv, 1854, 398, Taf. xv,Fig. 1-6. t Actinophri/a oeulaia. Stein: Die Infusionstbiere, 1854, 151, 157, Taf. v. Fig. 25. Organismus Infusions- thiere, ii, 1867, note to p. 5, "A. ovulaia nur eine marine Form von^. sol." — Pritcbard: Hist. Infus. 1861, 560, pi. xxiii, figs. 24, 25. Animal spherical, translucent, vesicular or foamy, the vesicles usually- numerous, more or less crowded and usually uniform. Contractile vesicle single, large, active. Nucleus commonly obscured from view. . Rays numer- ous, straight, from one to three or four times the length of the diameter of the body. Sise. — Diameter of body from 0.04 mm. to 0.12 mm., with pseudopods commonly from 0.08 mm. to 0.16 mm. in length. Locality. — In all quiet waters with aquatic plants. Observed in many parts of the United States, Nova Scotia, and Canada. Actinophrys sol, the <;ommon Sun-animalcule, is one of the most familiar and striking forms of microscopic life of still fresh waters. When first seen, it would hardly be suspected to pertain to the animal kingdom, though Joblot, its earliest observer, spoke of it as "a fish the most extraor- dinary that one may see." Plate XL. It may be found in almost every standing water-pool, pond, or lake, swimming among aquatic plants; its favorite haunts being duck-meat, hornwort, bladderwort, or the various filamentous algae. It commonly appears as a globular, hyaline, foamy or vesicular body, bristling with delicate rays, and suspended almost stationary in the water. 236 FKESH-WATEE EHIZOPODS OF NORTH AMERICA. The body of Adinoplirys sol is soft and elastic, and though ordinarily spherical, occasionally, by feeble contraction, exhibits a slight change from the regular outhne of form. Its surface is not even, but wavy or botryoidal, though sometimes this appearance is hardly evident. The body is composed of a basis of colorless, hyaline protoplasm with diffused, pale, granular matter and fine oil-like molecules. The protoplasm is crowded with clear globules or vacuoles, of comparatively uniform size, which give the body the appear- ance of being a foamy mass. Often these globules are so numerous, that the body of the Actinophr3's appears to be made up of them, with barely sufficient protoplasm to hold them together and give to the whole a thin investment. When crowded, they become more or less polyhedral; and those at the periphery project slightly beyond the general outline, so as to give it the botryoidal appearance. Though usually of comparatively uniform size, they may vary considerably in different individuals and occasionally in the same individual. See figs. 1—5, 7—10. Rarely have I seen what I have taken to be an individual of Actino- phrys sol in which vacuoles, excepting the contractile vesicle, were altogether absent, as represented in fig. 6. A large nucleus occupies a central position of the body, but is rarely even indistinctly visible, until brought into view by artificial means, — the action of acetic acid or other chemical reagent. AVhen seen, it appears as a pale, faintly granular ball containing a darker nucleolus. On one occasion I observed an individual, as represented in fig. 5, in which a nucleus was very distinctly visible. The animal appeared to be undergoing dissolution, and the figure represents it as first seen. The body consisted .of a mass of granular protoplasm, with a single layer of large vacuoles occupying the periphery, and from it there projected only five pseudopodal rays. The animal was stationary and its vacuoles quiescent, but after a time several of these slowly expanded and became more prominent, then successively collapsed, and after an hour all had disap- peared, leaving the body in a shriveled condition. The nucleus remained persistent, and was more distinct at last than at first. It was globular, and contained many granules of uniform size and a large central nucleolus. Commonly, at some portion of the periphery of the body oi Adinoplirys sol, there appears a contractile vesicle. At one moment it may be undistin- guishable from the contiguous vacuoles, but becomes evident from its GENUS ACTINOPHEYS— ACTINOPHEYS SOL. 237 slowly expanding and rising above the surface of the body, looking like an air-bubble floating on water. Reaching its full size as a sphere, half imbedded in the foamy-looking structure of the body, on a sudden it col- lapses, and a shght sinking occurs of that part of the body in which it was situated. The collapse of the contractile vesicle and the discharge of its contents impart a feeble tremor to the whole body, and this tremor may often be noticed, evidently from the same cause, even when the contractile vesicle is out of sight. The reappearance of the contractile vesicle commonly takes place in the same position that it previously occu- pied. Gradually expanding, it rises as a film of granular protoplasm, which, becoming thinner and thinner, finally bursts, and gives exit to the liquid contents. The interior of the body of Adinophrys sol frequently exhibits, among its clear vacuoles, a variable number of colored and colorless granular balls, which are often included in liquid drops or vacuoles. These are food-balls, and may be situated at various depths from the surface. The colored balls are usually green, dependent on algse or zoospores used as food, or they may appear brownish or reddish, due to changes produced by digestion. The pseudopods o{ ActinopJirys sol are ordinarily very numerous, though variable. They are delicate extensions or rays from the granular proto- plasmic basis of the body, and are commonly so straight and fixed in position as to resemble fine acicular crystals. They are, however, quite flexible, so that when the animal is accidentally pressed against a resisting body they will bend like the hairs of an artist's pencil. They are retractile, though the animal ordinarily seems so little sensitive that they remain projected, notwithstanding any disturbance. They range in length equal to the diameter of the body, to two, three, or more tunes that extent. Grenacher, and Hertwig and Lesser, describe the pseudopodal rays as being sustained by an axial thread of firmer consistence than the granular protoplasm occupying the exterior. I have been unable to confirm the statement of these authorities, and to me the pseudopodal rays seem to be nothing more than the most delicate filaments of viscid granular protoplasm. Actinophrys sol ordinarily remains almost stationary in position sus- pended in water, but closely watched it is observed to ghde slowly through its element without obvious cause, but probably as the result of some not easily detected action of the numerous rays. 238 FEESH-WATEE EHIZOPODS OF N^OETH AMEEICA. The animal feeds on infusorians, rotifers, unicellular algse, and zoo- spores. Active animalcules, in coming into contact with the rays of Actino- phrys sol, in most instances appear to become more or less paralyzed. The smallest infusorians or algse brought into contact with the rays glide slowly along them to their base. Larger and more active animalcules and zoospores, coming into contact with the rays, will cause several together to retract and draw the food to the body. When near or in contact with the latter, a portion of clear protoplasm is projected to involve the prey, in quantity according to the size and struggles of the latter. Fig. 1, pi. XL, represents an individual, which, with others, was sur- rounded by a multitude of bright green, actively moving zoospores.* As one of these came into contact with the rays of the Actinophrys, it became instantly motionless. Gradually the zoospore was drawn inwardly by means of one or more retracting rays, and, when within a short distance of the body of the Actinophrys, a portion of clear protoplasm was pro- jected to receive it. Becoming involved in the process of protoplasm, this, together with the zoospore, was slowly withdrawn into the interior of the Actinophrys, where, within a clear globule, it assumed the shape of a green ball. In the process of digestion, the green balls became brown, and occasionally in this condition one would gradually approach the surface of the Actinophrys and suddenly be expelled. Fig. 2 represents an Actinophrys sol, wliich, while under examination, received upon its rays an active Euglenia. This, in its struggles, produced much disorder among the rays of its captor, but withal was drawn toward the body and received by a large flow of clear protoplasm. The Euglenia continued its struggles, which caused a greater effusion of the latter. At one moment it appeared as if the Euglenia would escape, but it became enveloped in an effused mass of protoplasm, which nearly extended around the semi-diameter of the body of the Actinophrys, and finally ceased all movements. The exuded protoplasm then gradually con- tracted into a hemispherical form, as seen in fig. 3, including centrally the Euglenia, now compressed into a ball. The pseudopodal protoplasm, con- tinuing to contract, was slowly withdrawn, together with the l"]uglenia ball, _ » __^_ * I do not know whether these are really zoospores or infusoria. They are bright green, oval with a central nucleus, and a colorless beak at one pole, but without flagellum. They measured 0.016 mm. bv 0.012 mm. GENUS ACTINOPHEYS— ACTINOPHEYS SOL. 239 into the body of the Actinophrys, when it presented the appearance seen in tig. 4. Green food swallowed by Actinophrys sol, ordinarily, in the process of digestion, becomes brown, and the remains are discharged from the surface. The common Sun-animalcule presents considerable range in size, the body measuring from one twenty-fifth to one eighth of a millimetre in diameter. Ordinarily it is from one twentieth to one twelfth of a miUime- tre, and the rays are from one to one and a half the length of the diameter of the body, but occasionally reach double that length or even more. Not unfrequently Actinophrys sol is met with of a dumb-bell-like form, apparently consisting of a pair of individuals as ordinarily seen, united by an isthmus, of variable extent, as represented in fig. 10. I'he animal in this condition has been considered to be in conjugation, that is to say, to consist of two individuals, which have conjoined for some purpose of a sexual kind. . I never happened to have the opportunity of seeing two indi- viduals in the act of conjunction. In all those cases in which I have met with the animal in the duplex state, on closely watching, they turned out to be cases of multiplication by division. In these instances, the isthmus uniting a pair gradually becomes narrower and longer, and then breaks, leaving the original dumb-bell form as a pair of spherical individuals. During the process of division, the animal glides about less actively, and the rays diverge in the usual manner from each ball, but are absent from the isthmus. Each ball also has its own contractile vesicle, which exhibits the ordinary rhythmical movements. The remains of food may also be discharged, as seen in fig. 10, a, but I have not observed the animal feed during the condition of segmentation. Though, as intimated, I have not had the opportunity of observing a pair of individuals of Actinophrys sol actually join and unite into one, I have occasionally met with a specimen of biscuit-shape outline, as in fig. 8, which, gradually contracting, assumed a spherical form, as in fig. 7. In the particular case represented, the specimen, when first noticed, contained four large clay-colored vacuoles, of which all but one subsequently, during the contraction of the animal, discharged their contents. On one occasion, having observed an Actinophrys sol of peculiar and unusual appearance, I was led to watch it, and continued to do so at inter- vals from 3 o'clock in the afternoon until midnight. It turned out to be an 240 FEESH-WATEE EHIZOPODS OF NOETH AMEEICA. instance of segmentation, as represented in figs. 11-22, but differing in the earlier steps from 'anything of the kind I had previously or since have seen. At first, the Aetinophrys appeared as a pair of ordinary individuals, retaining between them a third spherical ball nearly as large, as seen in fig. 11. The nature of this intervening ball I did not discover, but conjectured that it was a third individual of Aetinophrys, altered from the usual con- dition. It was granular, without vacuoles and rays, darker on one side than the other, and with a central clearer spot, probably indicating the presence of a nucleus. Three hours subsequently the pair of Actinophry es remained essentially unchanged, but were united by a cylindrical isthmus, which contained the third ball reduced to little more than half its original size, and with a less distinct outline,* as represented in fig. 12. Two hours later the two Actinophryes remained unchanged, but the isthmus had become rather longer and narrower. The intervening ball had melted away, leaving in the isthmus, besides diffused granular matter, a large clear nucleus and a group of fat globules. See fig. 13. Soon after, the two Actinophryes remaining unchanged, excepting a slight flattening at the opposite poles, the isthmus became narrowed on the left and retained the nucleus and oil globules on its right, as seen in fig 14. At the next step, the two Actinophryes increased in diameter in a direction opposite to that transverse with the isthmus, and became sunken at the opposite poles, as seen in fig. 15. The isthmus continued to become narrower until it formed a mere cord, and the nucleus, together with the oil globules, were drawn into the Aetinophrys on the right, as seen in fig. 16. About 9 o'clock the isthmus parted, and the two Actinophryes appeared as represented in fig. 17: the individual on the right being cordiform; that on the left reniform. Later, the reniform individual, or that on the left, assumed a dumb-bell form, fig. 18^ its isthmus then gradually narrowed and elongated, fig. 19, and finally parted into two individuals. The cordiform Aetinophrys, or the individual on the right (fig. 17), produced in the divi- sion of the original pair, contracted at the point, so that it became reniform, as seen in fig. 20. This now, still retaining the apparent nucleus and oil globules of the above described granular ball, also assumed a dvimb-bell * The outline has been made too dark in the lithograph ; in the original drawing there is none. GENUS ACTINOPHRYS— ACTINOPHEYS PIOTA. 241 form, as seen in fig. 21. The isthmus of the latter then elongated, and containing within it the nucleus and oil globules, fig. 22, in this condition the Actinophrys nearly resembled the third stage, fig. 13, of the original specimen. It was now midnight, and I was obliged to retu-e from my observations. The next morning I could find nothing in the animalcula- cage but a half dozen individuals of Actinophrys having the ordinary appearance. During the whole time the Actinophryes retained their usual charac- ters, with numerous rays divergent everywhere except from the isthmus, and always a contractile vesicle exhibiting its ordinary rhythmical movements. Another mode of reproduction of Actinophrys sol, as observed and described by Cienkowski,* I have not had the opportunity of seeing. Ac- cording to this able investigator, the animal, preparatory to the reproductive process, withdraws its rays and becomes a closed cell by the formation of an exterior, sharply defined, investing membrane. The body loses its foamy character, and becomes finely granular and more condensed centrally. The more compact central px)rtion after some hovu-s divides into two masses, and the exterior membrane with the remaining peripheral matter, excepting a few granules, dissolves away. The pair of isolated balls then acquire each an investing membrane, and the granular contents become somewhat retracted from their wall, and are then provided with an additional investing membrane. Finally, from each cell thus formed, a young Actinophrys makes its escape. / ACTINOPHRYS PICTA. / Plate XJuVT, Sg. 4. Animal hiwing the same constitution and habit as Actinophrys sol, but with the body of a bright green color, due to the presence of chlorophyl mingled with the colorless granular protoplasm. Si^e. — From 0.056 mm to 0.105 mm. in diameter. Locality.— Fonds in sphdgnous swamps at Absecom, Vineland, and other localities in New Jersey. Actinophrys picta, as represented in fig. 4, pi. XLVI, closely resem- bles the common Sun-animalcule, but possesses a bright green color. The globular body has the same foamy aspect, but the protoplasm occupying * Archiv f. mik. Anatomie, 1865, 227. 16 EHIZ 242 FEESH-WATEE EHIZOPODS OF NOETH AMERICA. the intervals of the nearly uniform, clear vacuoles, is mingled with bright green chlorophyl granules. A thin layer of protoplasm at the surface of the body is free from the latter, and gives off numerous simple rays, as in Actinophrys sol. A single contractile vesicle presents the usual phenomena, as in the latter. Actinophrys picta is comparatively rare, and I have found it only in the ponds of cedar and sphagnous swamps in New Jersey. It may be the same as the Actinophrys viridis of Ehrenberg, though I believe the weight of evidence is in favor of the latter being the more common Heliozoan hereafter described as Acanthocystis chcetophora. The size of the green Sun-animalcule above described is about 0.1 mm., with the rays of the same length. With the preceding I have observed bright green Heliozoans, as rep- resented in figs. 5, 6, which may pertain to the same animal, though they possess some peculiarity. The body, instead of having a foamy appearance, as in Actinophrys sol, is composed of colorless granular protoplasm, with numerous but variable proportions of bright green chlorophyl corpuscles. These are much larger than the green granules of the animal above referred to Actinophrys picta, and are especially accumulated in an intermediate zone of the body. A clearer central spot indicates the presence of a nucleus. A contractile vesicle was observed in the usual position, as in Actinophrys sol, and as seen in fig. 5, but it was less active in its movements, and in some individuals was not detected or appeared not to exist. The pseudopods have the same character as in Actinophrys sol, but commonly were fewer, and often coarser. Individuals range from 0.056 mm. to 0.1 mm. in diameter, with the rays about equal in length to the latter. The green chlorophyl corpuscles measure from 0.004 mm. to 0.006 mm. HETEROPHRYS. Greek, heteros, diverse ; ophrus, an eyebrow. Animal resembling Actinophrys in general form, constitution, and habit, but ordinarily with the body enveloped with a thick stratum of proto- plasm defined by a granulated or thickly villous surface, and penetrated by the pseudopodal rays. GENUS HETEROPHEYS— HETEEOPHRYS MYEIAPODA. 243 HETEROPHRYS MYRIAPODA. Heterophrya myriapoda. Archer: Quart. Jour. Mic. Sc. 1869, 267, pi. xvii, fig. 4; Ibid. 1870, 110.— Greeff, Arch. mik. Anat. 1875, si, 21, Taf. i,rig. 8, 9?. f Beterophrys variana. Schulze : Arch. mik. Anat. 1874, x, 386, Taf. xxvi. Fig. 2-5. f ffeterophrys variabilis. Greeff: Arch. mik. Anat. 1875, xi,28, Taf. ii,Fig. 20-23. Body composed of a soft, usually spherical, granular mass of proto- plasm, colorless at the surface, and commonly bright green in the interior, due to the presence of variable proportions of chlorophyl corpuscles, or in some conditions with little or no color independently of that produced by food ; also containing clear colorless corpuscles, vacuoles, nuclei, and one or more contractile vesicles. With or without an exterior envelope of clear, colorless protoplasm defined at the surface by granules or cil-like villi. Pseudopods as simple granular rays. Size. — Diameter ^^th to g^th of an inch (Archer). Locality. — Ireland (Archer) ; Germany (Schulze, Grreeff). The genus Heterophrys, established- by Mr. Archer, consists of Actino-< phrys-like animals, the body of which usually contains colored corpuscles, and is invested with a layer of protoplasm defined by a ciliated or gi-anu- lated surface, and penetrated by the pseudopodal rays. To the genus Mr. Archer refers a creature of gregarious habit, previ- ously described by Focke (Zeitschrift fiir wissenschaftliche Zoologie, 1868, 353, Taf. XXV, Fig. 1), and gives it the name of HeteropJirt/s Fockii. This I am disposed to view as pertaining to RapUdiophrys elegans, hereafter to be described. Heterophrys myriapoda, as described by Mr. Archer, is a beautiful, bright green, Actinophrys-Hke animalcule, having the body enveloped in a thick layer of granular protoplasm defined by a villous surface and pene- trated by numerous simple rays like those of the common Sun -animalcule. Professor Schulze has described a colorless heliozoan, which he attri- butes to the same genus under the name of Heterophrys varians. He indi- cates two conditions of the animal : one in which the body is surrounded by a clear protoplasmic layer defined by a granular surface; the other in which this layer is absent. The interior contained from three to half a dozen nuclei and a variable number of contractile vesicles. The size of the body was about 0.06 mm. 244 FEESH-WATEE EHIZOPODS OF NOETH AMEEICA. Apparently the same animal has been described by Professor GreefF ■vvith the name of Heterophrys variabilis. It contained variable proportions of colored granules, green and red, together with colorless vacuoles and nuclei. The body possessed a transparent, colorless envelope, defined at the surface by minute linear particles. The size of the animal with its envelope was 0.06 mm. It is probable that the forms described by Professor Schulze and Pro- fessor Greeff represent different conditions of the form described by Mi*. Archer as Heterophrys myriapoda. In many instances I have observed colored Actinophrys-like animal- cules, of uncertain reference, resembling Heterophrys, but devoid of its cloak of protoplasm. I have suspected, however, that the latter belongs to one stage of the animal's existence, and in another stage may be absent. If this view is correct, it is probable that the forms referred to Actmophrys picta, and those allied to it, may belong to Heterophrys. Animals of the same general character, probably referable to several different species, are represented in figs. 1-6, pi. XLV, and figs. 7—13, pi. XLVI. Forms like those of figs. 7-9, pi. XLVI, are not unfrequent in the ponds of sphagnous swamps in New Jersey. The body of the Heliozoan is commonly spherical, but capable of changing its shape. It is composed of soft, homogeneous, granular protoplasrn, with or without minute oil molecules, colorless at the surface, but variably green and yellowish or brownish in the interior. It usually exhibits neither vacuoles nor contrac- tile vesicles, and commonly a central nucleus, if present, is obscured from viev/. The pseudopodal rays, generally fewer, are often longer and coarser than in Adinophrys sol, but have the same composition. They are quite changeable in form; usually tapering and simple, they sometimes fork at an acute angle. In the elongation of the body of the animal, the poles often appear more or less abruptly tapering into one or several of the coarser pseudopodal rays. Sometimes the rays become clavate or thickened as they proceed outwardly, and rarely I have seen one or more divide in a brush-like manner at the distal extremity. Commonly straight, they Avill sometimes become quickly tortuous, especially in the act of retraction, and sometimes they become beaded in appearance. Occasionally some of the finer ones will form a little ball at the end, so as to resemble the pin-like suctorial rays of Acineta. GENUS HETEEOPHEYS— HETEEOPHETS MYEIAPODA. 245 Fig. 7 represents an individual from Absecom pond, obtained in September, exhibiting the different changes which occurred in the pseudo- podal rays during the time the animal was observed. Figs. 8, 9, represent two views of another individual, found with the former, exhibiting successive changes, both in the shape of the body and the pseudopodal rays. At first spherical, it became elliptical, and again assumed the former shape, when it measured 0.02 mm. in diameter. An individual of the same kind, from a sphagnous swamp of Broad Mountain, Pennsylvania, is represented in fig. 12. As first noticed, the body was globular, with numerous simple rays projecting from one hemi- sphere, but later they emanated from all parts of the surface. The interior was composed of colorless granular protoplasm with fine oil-like molecules, greenish and yellowish granules, and a few bright-red ones. It also con- tained a large oval body, probably something swallowed as food, but the character of which was not ascertained. Neither nucleus nor contractile vesicle was seen. Another individual, apparently of the same kind, represented in fig. 11, was obtained, in association with others, with the alga Lyngbya, from a roadside gutter in the suburbs of Philadelphia. The soft body of a dif- fused green hue, except at the surface, which was colorless, contained many red-colored objects, which appeared to be segments of the Lyngbya used as food and changed in color by digestion. Similar Heliozoans, from bog- water obtained in the Uinta Mountains, Wyoming, are represented in figs. 1-3, pi. XLV, and fig. 13, pi. XLYI. In constitution and habit they resembled the former, but they were usually yellowish, with a few bright-red granules, though sometimes they were also partly greenish. In all, a pale central nucleus was more or less distinctly visible, and usually some clear globules or vacuoles. The individual of fig. 13, pi. XL VI, contained a number of scattered corpuscles of different sizes and colors,— green, dull yellow, and red. These I supposed to be one-celled algse in various stages of digestion. At first elliptical, the animal afterward became spherical, and measured 0.028 mm. in diameter. The individual of fig. 1, pi. XLV, contained some diffused yellowish and greenish granular matter mingled with the otherwise coloriess proto- plasm. It also contained some oil molecules and clear vacuoles 246 FEESH-WATEK RHIZOPODS OF NORTH AMERICA. The individual of fig. 2, obtained at the same time with the preceding, was composed of homogeneous, finely granular, and colorless protoplasm, with fine yellowish granules intermingled. As food, it contained a diatom and a few brown balls, of which two were afterward seen to be discharged. It also contained a number of clear globules, of which the largest one was observed to collapse, though it did not reappear in the manner of a con- tractile vesicle. Pseudopods projected mainly from one hemisphere, and the animal slowly moved in that direction at the rate of about one millimetre in nine minutes. The creature, on coming into contact with a Closterium, gradually changed from the globular to a three-sided shape, then became oval, and finally again spherical as it moved away from the alga. The individual of fig. 3, also found with the preceding, appeared to have its opposite poles rather abruptly prolonged into several of the coarser pseudopodal rays. It contained some scattered colorless and red-colored corpuscles, together with a large vacuole, which remained unchanged. A green Heliozoan, resembling those just described in the changeable form of its body, is represented in fig. 10, pi. XL VI. It was found, with several others of the kind, in Absecom pond, in the month of May. The body is composed of a basis of soft, colorless, granular protoplasm, with green granules diffused through it, but more abundant centrally, where they appear to obscure the nucleus from view. Several contractile vesicles were observed at the periphery. As first seen, the body was elliptical, with the opposite poles giving off the two strongest pseudopodal rays. A large vacuole, containing a food-ball, was in the act of being withdrawn. The creature afterward assumed a spherical form, and then measiired one seventh of a millimetre in diameter. Later, an active rotifer came into contact with the Hehozoan, and ceased movement as if paralyzed, but after a moment it recovered and attempted to move away. It was, however, restrained by a protruding hemisphere of clear ectosarc, and in the struggle the Heliozoan appeared to be extended toward its victim, and the rays of the same side converged to it. Finally, the rotifer succeeded in making its escape. The portion of clear protruded protoplasm projected several rays, and was then slowly withdrawn, and gradually the Heliozoan assumed once more a spheroidal shape. A small colorless Heliozoan, represented in fig. 4, pi. XLV, probably GENUS HETEEOPHEYS-HETEEOPHEYS MYEIAPODA. 247 pertains to Heterophrys, and resembles the H. Fockii described by Mr. Archer.* It also resembles a form described by Professor Greeff, and with doubt considered to be the young oi Acanthocystis viridis.f The individual was obtained in August, from a pond in a sphagnous swamp, at Vineland, New Jersey. It resembled the Actmophrys sol, but was of less uniform foamy aspect, being composed of a spherical mass of pale granular protoplasm, with a number of clear globules or vacuoles of various sizes scattered through it. The body was enveloped in a thick layer of clear protoplasm rising in wave-like points on the pseudopodal rays. An enigmatic body of uncertain reference, of which two views of the same individual are given in figs. 5, 6, pi. XLV, may perhaps pertain to Heterophrys. It was obtained in July, from a ditch in which grew Hippuris vulgaris, at Fort Bridger, Wyoming. When first observed, it was nearly spherical, and resembled in general appearance au Actinophrys, but was of a red hue, and was enveloped with a thick layer of colorless proto- plasm defined by a minutely dentate outline. The body measured 0.04 mm. in diameter, and consisted of a basis of colorless, faintly granular protoplasm mingled with red granules of varied depths of hue, difi'used and partially collected in irregularly rounded masses. It also contained two large clear globules, probably nuclei, which remained unchanged during the time the creature was under examination. The rays were compara- tively few, and appeared as abruptly tapering processes of the superficial colorless protoplasm of the body. They varied in length and degree of robustness, and were mainly straight and simple, though a few of the stronger ones were furcate. The stratum of protoplasm enveloping the body was clear, and appeared to have a finely echinate or granular surface. Sometimes the granules appeared to be connected with fine perpendicular striae, extending through the cloak of protoplasm, as seen on one side of fig. 6, so as to resemble the pin-like rays of Acineta ; but the appearance was uncertain, and may have been deceptive. As the animal moved in the same slow, gliding manner of an Actino- phrys, it gradually underwent a variety of changes in shape. Becoming * Quart. Joiir. Mic. Sc. 1869, pi. xvi, fig. 3. t Arcliiv f. mik. Auatomie, 1869, Taf. xxvii. Fig. 35. 248 FEESH- WATER EHIZOPODS OF NOETH AMEEIOA. elliptical and then elongated pyriform, a small portion, of elliptical shapCj gradilally extended itself from the main portion, and retnained connected with it by a narrow isthmus of clear protoplasm, in which condition the animal presented the appearance seen in fig. 5. Watching the creature with the expectation of seeing the smaller portion separate and become a dis- tinct individual, after some time it was observed to be gradually withdrawn into the main portion. Subsequently the animal became ovoidal, and then assumed an irregularly quadrate outline with festooned borders, as repre- sented in fig. 6. Later it continued to undergo changes of the same general character so long as it was convenient to observe the animal. This creature bears some resemblance to the subjects of Focke's figs. 2, pi. XXV, of the Zeitschrift fiir wissenschaftliche Zoologie for 1868. ■ EAPHIDIOPHEYS. Greek, rapMs, a needle ; ophrus, an eyebrow. Animal ordinarily associated in groups of variable number, closely aggregated or conjoined by isthmus-like bars. Individuals of Actino- phryan form, consisting of a soft spheroidal body of granular protoplasm, with oil-like molecules and variable proportions of clear colorless or bright green corpuscles, and with a large central nucleus. Exterior of the body invested with a thick layer of delicate, colorless protoplasm, extending in tapering processes on the pseudopodal rays and densely pervaded with minute spicules tangentially arranged. Pseudopodal rays very long, numerous, straight, simple, and finely granular. EAPHIDIOPHEYS VIRIDIS. Maphidiophrys viridis. Arclier: Quart. Jour. Mic. Sci. 1870, x, 103, pi. xvi, flg. 2. Animal single, or more commonly in closely aggregated groups of variable number. Individuals more or less bright green from the presence of chlorophyl corpuscles (and probably at times colorless from the absence of these). Spicules of the exterior envelope thickly distributed and extending outwardly on the bases of the pseudopodal rays, comparatively coarse and slightly bent. Sise.^Ahout ^ih of an inch (Archer). Locality. — Irela nd. GEl^US EAPniDIOPHEYS— EAPHIDIOPHETS VIEIDIS. 249 Raphidiophrys viridis, a remarkable Actiuoplnys-li'ke animal, of gregarious habit, was discovered in Ireland by Mr. Archer. From the origi- nal description and figure, it consists of a close aggregation of a number of spherical individuals of a bright-green color, enveloped together in a pale yellowish layer of protoplasm pervaded with numerous shghtly bent spicula, apparently silicious in character. In several instances I have observed Heliozoans which I have sus- pected to be isolated individuals of the above species, but of this I cannot be positive. A specimen, from Absecom pond, New Jersey, supposed to pertain to Raphidiophrys viridis, is represented in fig. 1, pi. XL VI „ The globular body was composed of a basis of pale, indistinctly granular protoplasm, with a number of bright-green chlorophyl corpuscles scattered through it, together with a smaller proportion of yellow and brown corpuscles. My first impression in regard to the character of these colored corpuscles was that they pertained to the food, and it may be that some portion of them did so. With them I observed a single diatom. A central nucleus was indicated by a clearer round spot, and on each side of the body there was an equally large vacuole, which remained unchanged during the examination of the animal. Pseudopodal granular rays emanated from all parts of the body, as in Actinophrys sol. The exterior of the body was invested with a layer of faintly granular protoplasm containing a profusion of delicate linear spicules, slightly bent. The spicules were in general arranged tangentially to the surface of the body and extended outwardly a short distance upon the rays. The body measured 0.09 mm. in diameter, and the longest rays exceeded the latter in length. Another Heliozoan, obtained with the preceding and represented in fig. 2, may probably belong to the same species, though exhibiting some peculiarity. The spherical body was composed of a finely granular, color- less protoplasm, containing a central nucleus, a number of va,cuoles, and a few colored corpuscles, mostly yellowish and brown, together with a few green single-celled algae. The surface of the body was. invested with spicules arranged tangentially, with a somewhat tufted appearance. The spicules were compara,tively coarse, nearly straight or feebly bent, and 250 PEBSH-WATBE EHIZOPODS OF NOETH AMEEICA. pointed at both ends. They resembled the simple spicules of the fresh- water sponges. The pseudopodal rays were numerous, simple, and long, like those of Adinophrys sol. Another Heliozoan, related with the preceding, is represented in fig. 3, and was found in the material adherent to a stone, on which grew a Spongilla, from the Schuylkill Eiver, at Philadelphia. The animal was entirely colorless. The spherical body, composed of pale granular proto- plasm, contained a central nucleus, and numerous scattered, clear globulus. Externally it was invested with a thick layer of protoplasm densely per- vaded with delicate, curved spicules, arranged tangentially to the body, and rising in pointed processes upon the pseudopodal rays. This creature resembles the Baphidiophrys pallida of Schulze,* and probably pertains to the same species. RAPHIDIOPHRYS ELEOANS. Plate XLII. ? Actinophrys oculata and Actinophrys Sol. Carter : An. Mag. Nat. Hist, xv, 1865, 277, pi. xii, figs. 1-3. Baphidiiophrys elegana. Hertwig and Lesser : Arch. mik. Anat. x, 1874, Suppl. 218, Taf. iv, Fig. 1. — Leldy : . Pr. Ac. Nat. Sc. Phila. 1874, 167.— Archer : Quart. Jour. Mic. Sc. 1876, 374, pi. xxii, fig. 19. SphcBraatrum canglobatum. Greeff : Arch. mik. Anat. xi, 1875, 29, Taf. ii, Fig. 24-26. ' f Sohalenlose Susswasscr-Badiolarien. Focke : Zeitschr. f. wissens. Zoologie, 1868, 353, Taf. xxv, Fig. 1. Animal single, or usually in gi-oups up to two or three dozen or more, separated by more or less wide intervals, and united by narrow bands or isthmuses. Individuals with the body more or less bright green from the presence of chlorophyl corpuscles, or colorless when the latter are absent. Spicules of the exterior protoplasmic envelope delicate, in the form of semicircles, and tangentially arranged, with their convexity directed toward the body and pseudopodal rays* Sise. — Diameter of the body 0.032 mm. to 0.04 mm. ; length of pseu- dopodal rays to 0.24 mm. ; length of the semicircular spicules 0.006 mm. Locality. — In springs and ponds among aquatic plants. Pennsylvania a;nd New Jersey. Raphidiophrys ele^ans, represented in pi. XLII, occasionally solitary, is commonly observed in groups of from five to twenty or more, and on one occasion I found an assemblage of thirty-eight individuals This remarkable creature, as usually seen, roaming about in flocks, appears * Archiv f. mik. Anatomic, x, 1874, 377, Taf. xxvi, Fig. 1. GENUS EAPHIDIOPHEYS— EAPHIDIOPHEYS ELBGAifS. 251 like an entangled mass of Actinophrys-like animals. The groups vary in form, but are more or less irregular. The individuals composing them have the shape and general appearance of an Actinophrys, and in the groups are associated by means of bands or bridges of protoplasm passing between those which are contiguous. The distance separating the individuals in different groups is variable, but mostly is less than the diameter of the body of the individuals. In active movement they are commonly farthest apart, and when at rest they become more closely aggregated. The individuals are usually spherical and of uniform size ; but they are capable of changing their shape, so that they may be oval or of some other form. The body is composed of a basis of soft, colorless, granular protoplasm, with fine oil molecules disseminated It contains variable pro- portions of bright green and colorless corpuscles, which exhibit some uni- formity of size. Sometimes the green chlorophyl corpuscles are numerous, sometimes comparatively few, and at times altogether absent. The color- less corpuscles mingled with the green ones are clear and homogeneous, and at times exist to the exclusion of the latter. The bridge-like bands passing between contiguous individuals of the groups vary in length and thickness, and are more or less temporary con- junctions composed of the protoplasmic basis of the bodies. At times they may be seen to shorten or elongate, to contract and to part, and the divisions withdraw; and at other times projected processes may be observed, which unite with contiguous ones to form new bridges Fre- quently green and other corpuscles may be seen traversing the bridges from one individual to another. The individuals contain a central nucleus, which, though usually ob- scured from view by the colored corpuscles and other constituents, some- times is distinctly visible, as seen in fig. 3. Though a distinct contractile vesicle, with rhythmical action like that of Actinophrys sol, appears not to exist in Baphidiophrys elegans, frequently a large vacuole is observed near the periphery of the body, which enlarges and collapses, to be replaced by a similar one in some other position. Hertwig and Lesser remark that they observed no contractile vesicle in this spedes, and Mr. Archer hkewise detected none in BapMdiophrys viridis. The pseudopodal rays of BapMdiophrys elegans are numerous and often 252 FEESH-WATEE EHIZOPODS OP NOETH AMEBIC A. very long. In solitary individuals they emanate from all parts of the sur- face, as in Actinophrys; but in the groups they commonly project from the exterior of the whole only. They are simple, delicate extensions of the granular protoplasm of the surface of the body. From their perfect straightness they seem to be rigid ; but they are highly flexible, and at times may be seen to bend in a bunch from the rude shock of a passing rotifer, like the hairs of a brush from the pressure of the fingers. Each and every individual composing a group is enveloped with its own cloak of transparent homogeneous protoplasm, which is, however, extended upon the bridge-like bands, and also extends in more or less long tapering processes on the pseudopodal rays. The protoplasmic investment is loosely pervaded with a multitude of delicate semicircular lines or spi- cules, which are arranged with their convexity tangentially to the bodies of the animals, and to the rays upon which they extend. Upon the surface of the protoplasmic investment they give a wavy or delicately festooned outline. Not unfrequently the interior of the body of some individuals con- tains brownish or reddish balls of variable size, sometimes large, as seen in fig. 4. These I have supposed to be food-balls, and of the same nature probably are some of the green globules viewed chiefly as pertaining to the structure of the animal Occasionally I have observed a group of JRapJiidiophrys elegans retaining among them large colored balls, as represented in fig. 6, the character of which I did nbt ascertain, though I supposed them to consist of discharged excrementitious matter. The individuals of BapMdiophrys elegans commonly range from 0.033 mm. to 0.04 mm. in diameter. The pseudopodal rays extend from 0.1 mm. to 0.2 mm. in length, but occasionally may reach 0.4 mm. The semicircu- lar spicules, which envelope the animals, are about 0.0125 mm in length. Baphidiophrys elegans is commonly more active in its movements than Adinophrys sol. The groups move in the same gliding manner, but more rapidly, and they continually change their shape. At first spheroidal, they may become oval or more or less quadrate, then elongate, and become conical, pyriform, or some other shape. The individuals of a group may approach or recede, break their bridge-like bands or establish others, or, as not unfrequently occurs, the large groups may break into two or more GENUS VAMPYEELLA— VAMPYEELLA LATEEITIA. 253 smaller ones. In the group of thirty-eight, above indicated, shortly after the observation it separated into three groups, of fifteen, thirteen, and ten. Raphidiophrys feeds, and it also discharges the remains of the food, in the same manner as Actinophrys. VAMPYEELLA. Ammia : Fresenius, 1856. Vampyrella : Cienkowski, 1865. Animal usually Actinophrys-like, with a soft spheroidal body, capable of amoeboid variations of form, composed of pale, colorless, granular proto- plasm, with abundance of coloring matter, oil-like molecules, and vacuoles. Pseudopods as Actinophrys-hke rays, Acineta-like rays?, and digit-like, lobate, or wave-like expansions. VAMPYRELLA LATERITIA. Plate XLV, figs. 10-16. Amaeiia lateiitia, Fresenius : Abh. Senck. Naturf. Gesells. ii, 1856-8, 218, Taf. x, Fig. 13-19. — Cienkowski : Jahrb. wis. Bot. iii, 1863, 428. Vampyrella Spirogyrm. Cienkowskl: Arcli. mik. Anat. i, 1865, 218, Taf. xii, xiii, Fig. 44-56. — ^Haeckel: Biolog. Studlen, 1870, 72. — Hertwig and Lesser : Arch. mik. Anat. x, 1874, Snppl. 61. — Archer : Quart. Jour. Mic. So. 1877, 347. Body brick- or orange-red, with hyaline periphery, commonly spherical, but capable of much change of shape. Pseudopods as Actinophrys-like rays, and lobate extensions, together with Acineta-like rays f According to Hertwig and Lesser, Vampyrella SpirogyrcB, originally described by Cienkowski, occurs mostly in an Actinophrys-like form, measuring 0.02 mm. to 0.075 mm. in diameter. The granular protoplasm of the body is pervaded with coloring matter of different shades of orange, reddish yellow, brownish yellow, and greenish. The coloring of the cen- tral portion is so intense as to obscure from view a nucleus, if one exists. The periphery of the body is hyaline, and contains several non-contractile vacuoles. The pointed pseudopodal rays frequently start from a common basis, and may fork, but do not anastomose Besides these, from time to time, broad, blunt, lobate, hyaline processes of protoplasm rapidly appear and disappear. In both kinds of pseudopodal extensions, peculiar move- ments of granules occur, in which they are quickly projected and withdrawn. Hertwig and Lesser observe, that so long as the Vampyrella retains its 254 FEESH-WATEE EHIZOPODS OF NOETH AMEEICA. • rounded form it so nearly resembles an Actinophrys, that an observer for the first time would be apt to take it for a colored species of the latter. Attention directed to it shows that it does not always retain the spherical form, but that, especially when it meets with algous filaments or similar objects, it withdraws part of its pseudopods, and adapts its shape to that of the object upon which it creeps. Its change is very striking when it becomes greatly elongated (to 0.24 mm.), and it creeps quickly across the field of view, reminding one of a caterpillar. Neither Cienkowski, nor Hertwig and Lesser, detected a nucleus in Vampyrella, and from its absence in a marine species, Vampyrella Gompho- nematis, described by Haeckel, this author has placed tbe genus in his proposed class of Monera* According to Cienkowski, the Vampyrella feeds only on the contents of the cells of Spirogyra Applying itself to a filament of the alga, the animal perforates a cell, and slowly transfers the contents, including the chlorophyl band, to its own interior. In the same manner it may apply itself to another cell, and so continue until its appetite is satisfied. Cienkowski remarks that the Vampyrella Spirogyrm appears to corre- spond with the Amoeba lateritia of Fresenius ; and so it has seemed to me, and in this view, according to the rules of zoological nomenclature, I have adopted the latter specific name. I had repeatedly observed a bright orange-colored Heliozoan the rela- tion of which for some time I did not recognize, even with the figures of Vampyrella by Cienkowski, and Hertwig and Lesser, before me, and it was only on reading the descriptions of the latter animal that I was led to regard the former as being the same. Vampyrella lateritia, represented in figs. 10-16, pi. XLV, as I now suspect it to be, and as it has come under my notice, is a brick-red or orange-colored Actinophrys-like creature, from 0.02857 mm. to 0.083 mm. in diameter. The body is a spherical, finely granular mass of protoplasm, with diff"used oil-like molecules. For a variable depth at the periphery it is color- less, but the great portion centrally is brick- or orange-red, of variable intensity of hue, and is sometimes mingled with a few darker granules of the same color. The mass of protoplasm may be nearly homogeneous, as seen * Studien fiber Moneron. Leipzig. 1870. Nachtriige ziir Mouograpliio der Moneren, 163, Taf. vi, Fig. 1-4. GENUS VAMPYEELLA— VAMPYEELLA LATEEITIA. 255 in figs. 10, 11, 13-15, or it may contain a few or numerous vacuoles, as in Actinophrys, ancl as represented in figs. 12, 16. A nucleus was not observed, and, if existing, is concealed from view by the surrounding mate- rial. Food, in the form of green algse, was noticed among the contents in several individuals, as represented in fig. 15. The pseudopodal rays of the creature under consideration, which I have taken for Vampyrella lateritia, have appeared to me to be of two kinds, one of the ordintCry character, resembling those of Actinophrys, while the others have reminded me of the suctorial rays of Acineta. The ordinary rays are delicate, straight, usually simple, and of very variable length; mostly shorter, sometimes longer than the diameter of the body. Not unfrequently several together start from the same base. They may project from a small portion or from the entire surface of the body; sometimes being confined to the semi-circumference or a smaller portion, and sometimes projecting everywhere, as in Actinophrys. The Acineta-like rays are pin-like, or consist of a short stem ending in a minute round head, and measure from 0.004 mm. to 0.0125 mm. in length. Like the ordinary rays, they may project from any part or the whole of the surface of the body at once; and they may be mingled indiscriminately with the former, or the two kinds may appear separated and issuing alone from opposite poles of the body. The pin-like rays are especially remarkable for the quickness with which they are successively projected and withdrawn. At times they are projected only in the slightest degree beyond the outline of the body, and. rarely to a greater length than 0.0125 mm. Sometimes an individual when first noticed exhibits only ordinary rays projecting from some portion or the whole surface of the body, and after a while the pin-like rays in variable number issue from some portion or the whole of the surface. Vampyrella glides along in the manner of Actinophrys, but commonly with more speed. Frequently, while in motion, the pin-like rays issue only on the side opposite to the direction of movement of the body, while ordi- nary rays may project alone on the other side, as represented in fig. 14. Commonly both kinds of rays are directed perpendicularly, but occa- sionally either may be seen projecting tangentially ; and while the pin-like rays are incessantly and rapidly pushed forth and withdrawn, the ordinary rays, usually apparently motionless, now and then are seen slowly to vibrate. 256 FEESH- WATER EHIZOPODS OF NO'KTH AMERICA. In the account of Vampyrella, previous observers do not indicate the existence of the peculiar pin-like rays as I have apparently seen and described them, but they refer to certain remarkable and similar move- ments of granules, with which the pin-like rays seem to accord It was not until after I made observations on the creature I have supposed to be Vampyrella, that I read the descriptions of the latter, and it has occurred to me that the appearance of the pin-like rays as above indicated may have been illusory. Since this view has occurred to me, I have not had the opportunity of repeating my observations. Besides the pseudopodal rays, Vampyrella frequently projects digit- like or lobular processes or broad wave-like expansions of clear or faintly granular protoplasm, as seen in figs. 10-13. These are quickly produced and as quickly disappear. In motion, the body of Vampyrella was occasionally noticed to undergo slight change of shape from spheroidal to oval; but I was not so fortunate as to observe it undergo the remarkable changes indicated by others. DIPLOPHRYS. Greek, dipUms, double j ophrus, eyebrow. Diplophri/s : Barker, 1868. Acanihocystis : Greeff, 1869. Cyatoplirys : Archer, 1869. IUfBorhanis : Greoflf, 1875. Animal minute, spheroidal, provided with a delicate, homogeneous, membranous investment, with a pair of oral orifices slightly lateral to the opposite poles. The interior, transparent, slightly granular protoplasm with a central nucleus, several pulsating vesicles, and usually a single, bright, yellow or red, oil-like globule. Pseudopods delicate, filamentous, and radiant in a tuft from both oral orifices. The young associated in groups, often of many individuals. DIPLOPHRYS ARCHERI. A minuie rhizopodoua form. Barker : Quart. Jour. Mio. So. vii, 1867, 232. Diplophryg Archeri. Barker: Ibidem, viii, 1868, 123. — ^Archer: Ibidem, 123. — Hertwig and Lesser : Arch. mik. Anat. x, 1874, Suppl. 139, Taf. iii, Fig. 9.— Greeff: Arch. mik. Anat. xi, 1875, 15, pi. i, Mg. 11-13.— Schulze : Ibidem, 127, Taf. vii, Fig. 10-15. Acanihocystis spiniferaf Greeff: Arch. mik. Nat. v, 1869. 495, Taf. xxvii, Fig. 24-29. Cystophrys oeidea. Archer: Quart. Jour. Mic. Sc. ix, 1869, 265, 421, pi. xvii, fig. 3; x, 1870, 18, 22, 101; xi, 1871, 144. A very minute w "Diplophrys-Uke" organism. Archer: Quart. Jour. Mio. Sc. ix, 1869, 323; x, 1870, 102; xi, 1871, 145, pi. vi, fig. 9, pi. vii, fig. 10. ElcBorhania dncta. Greeff: Arch. mik. Anat. xi, 1875, 23, Taf. i, fig. 10. GENUS DIPL0PHEYS-DIPL0PHET8 AECHEEI. 257 Biplophrys archeri, in its mature individual condition, is described by Professor Schulze * as a minute globular body, 0.01 mm. to 0.02 mm., from opposite poles of which there radiates a tuft of fine and mostly unbranching pseudopods. The transparent, faintly granular protoplasm composing the body contains a bright refractive corpuscle of variable size, usually of an amber color, less frequently paler or even colorless, and some- times light ruby red. I have not observed Diplophrys in the isolated and mature condition; it having perhaps escaped my attention from its very diminutive size. On several occasions I have seen what I have supposed to be the young con- dition, in which numerous individuals were associated in a coherent mass, resembling similar groups described and figured by Professor Greeff and . Mr. Archer. Professor Greeff f has suggested the probability of such a group, represented in his fig. 29, pi. xxvii, and other forms, figs. 25-28 of the same plate, more characteristic of Diplophrys archeri, having a genetic relation with Acanthoc^stis spinifera. A similar group Mr. Archer referred to another animal, distinct from Diplophrys, with the name of Cystophrys oculea.X Subsequently Professor Greeff § recognized the foims represented in his figs. 25-28, above indicated, as belonging to Diplophrys archeri, and further became convinced that the group represented in his fig. 29, pre- viously described by him without name, together with the Cystophrys oculea of Archer, were colonies of Diplophrys archeri, probably resulting ffom segmentation. The rhizopodal groups which I have observed, and regarded as per- taining to Diplophrys archeri, were obtained in sphagnous bog-water, on Broad Mountain, Schuylkill County, Pennsylvania, September, 1876, and at Atco, New Jersey, October, 1877. The groups were composed of multitudes of minute globular indi- viduals aggregated in masses, which in theit movements slowly underwent change of shape. A group closely aggregated and nearly spherical measured about 0.04 mm. Gently gliding across the field of view, it * Archiv f. mikros. Anatomic, xi, 1875, 127. t Ibidem, v, 1869. t Quart. Jour. Micros. Science, ix, 1869, pi, xvii, fig. 3. ji Arcliiv f. mikros. Anatomic, xi, 1875, 15. 17 EHIZ 258 PEESH-WATER EHIZOPODS OF NOETH AMEEICA. gradually assumed an oval and then an irregnlarly five-sided shape, as represented in fig. 8, pi. XLV. Continuing its slow changes, it elongated to more than double its former extent, becoming narrower and constricted toward the middle, as seen in fig. 7. In the latter condition, the group was more spread, thinner, paler, and more translucent, and the individuals more widely separated. Later the group rather suddenly shortened to an oval shape, then became irregularly quadrate, reniform, and so on. Another group, when first noticed, was biscuit-shaped, and as it slowly moved along, a break occurred near the centre, through which, by a slight change of focus, a deeper layer of individuals could be seen, apparently indicating the group to have formed a hollow mass. The individuals composing the groups of Diplophrys have appeared to me to be associated by means of a transparent protoplasm ; but the exist- ence of this has been denied by Hertwig and Lesser, in opposition to similar views expressed by Archer, GreefF, and Schulze. Hertwig and Lesser describe the larger groups or commiunities as being made up of smaller ones associated in fours; but such did not appear to be the case in the few examples which came under my observation. The individuals composing the groups were of pretty uniform size, globular in shape, and measured 0.004 mm. to 0.005 mm. in diameter; therefore considerably smaller than those described by Hertwig and Lesser. They were transparent, and contained mostly a single, bright cherry-red corpuscle, o^il-like and highly refractive. The presence of the large red coi-puscles so far concealed everything else that I failed to detect a nucleus. The pseudopodal rays were numerous, and diverged irregularly from all parts of the surface of the gi-oups. They were exceedingly delicate, straight, .simple, non-granular, and from 0.02 mm to 0.04 mm. long. I could not trace a connection between them and the individuals, and sus- pected that they emanated from a common enveloping protoplasm, accord- ing to a similar view of Professor Schulze. » AOTINOSPH^RIUM. Greek, ahim, a ray ; sphaira, a spheie. Body spherical or oval, composed of finely granular protoplasm en- closing a mass of delicate polyhedral vesicles or vacuoles occupied by a clearer hyaline protoplasm. The outer one or two layers of vacuoles more GEISnJS AOTINOSPR^EIUM— ACTmOSPH^EIUM EIOHHOENIL 259 or less distinctly defined from the interior mass by greater size, translu- cency, and apparently the intervention of a thicker film of granular pro- toplasm. Nuclei numerous and imbedded in the latter beneath the periph- eral vacuoles. Contractile vesicles two, commonly occupying opposite positions in the peripheral vacuole layer. Rays numerous, consisting of tapering extensions of the granular protoplasm, including an axis thread, which starts from the body beneath the peripheral vacuole layer. ACTINOSPH^RIUM EICHHORNII. Plate XLI. Der Stern. Eichhom : Beitr. Kennt. Wasserth. 1783, 15. AcHnoph-yg Hichhrn-nii. Ehrenberg: BerichtPreus.Ak. Wis. 1840, 198.— Stein: Infusionsthiere, 1854, 148, 151. — Claparfede and Lachmann : Etudes Infusoires, i, 1858, 9, 450. — ^Pritcliard: Hist. Infu- soria, 1861, 560.— H.T,eckel : Eadiolarien, 1862, 165.— Wallich : An. Mag. Nat. Hist, xi, 1863, 444, pi. X, figs. 1-3.— Cariier: Ibidem, 1864, xiii, 35, pi. ii, fig. 21; 1865, xv, 281, 283, pi. xii, fig. 6.— Cientowski : Aich.mik.Anat. i, 1865, 227, 229.— Greeff: Arch. mik. Anat. iii, 1867, 396. — ^Micrographic Dictionary, pi. 23, fig. 7 a. — Schneider : Zeitsch. wis. Zool. xxi, 1871, 507. Aetinophrye sol. KoUiker : Zeitsch. -wis. Zool. i, 1849, 198. AcMnoaphiBriwm Mchhomii. Stein: Sitzungsb. Bohm. Geselis. Wis. 1857, 41. — Greeff: Sitzungsb. uieder- rhein. Gesells. Bonn, 1871, 4. — Schulze: Arch. mik. An.at. x, 1874, 328, Taf. xxii. — Hert- wig and Lesser : Arch. mik. Anat. x, 1874, Suppl. 176, Taf. v. Fig. 1. — Leidy : Pr. Ac. Nat. Sc. 1874, 166. Body transparent, colorless, usually with a single peripheral layer of the large vacuoles, which are deeper than broad ; or, in the larger or older individuals, sometimes with two peripheral layers of vacuoles of more uni- form diameters. Sise — Ranging from 0.088 mm. to 0.4 mm. in individuals of globular form, with rays to 0.22 mm. in length; in individuals of oval form, from 0.26 mm. by 0.24 mm. to 0.68 mm. by 0.65 mm., with rays as in the former. Locality. — In ponds, lakes, and ditches, among Ceratophyllum, Lemna, and other aquatic plants, in Pennsylvania, New Jersey, and the Uinta Mountains of Wyoming Territory. Actinosphserinm eichhornii commonly looks like a giant form of the common Sun-animalcule, but is usually readily distinguishable, even in the smallest individuals, by a more or less well-marked distinction of the peripheral layer of vesicles from the interior mass. It varies greatly in size, and, though less frequent than Actinoplrys sol, is found in similar positions, and possesses nearly similar habits. See pi. XLI. The body is mostly spherical, but often in the largest individuals is oval. It forms a colorless, hyaline, vesicjilar. ball, with a clouded interior 260 FEESH-WATER EHIZOPODS OF KOETH AMEEICA. and a^learer^gerifiheraljajer. The latter, as seen in the various figures of pi. XLI, consists of a single, stratum of large clear vesicles or vacuoles, forming mostly short six-sided columns, resting by their narrower end on an interior ball of smaller polyhedral vesicles, and with the opposite end free and convex, and contributing to the general surface of the body. The superficial vesicles are nearly uniform, but not unfrequently vary, and sometimes a pair of vesicles of more uniform diameters substitute the ordi- nary short columnar vesicle. The interior vesicles, besides being in general smaller than the exterior ones, are more regularly polyhedral and of greater uniformity in their several diameters. The vesicles are composed of a thin, delicate, protoplasmic layer, con- taining apparently a more liquid and homogeneous protoplasm within. They appear to be held together and invested with a more granular proto- plasm with diffused oil molecules. A thicker stratum of this material ap- pears to define the peripheral layer of vesicles from the deeper mass, and a greater proportion also appears to extend between the vesicles of the latter. From this more granular protoplasm investing the body of the animal, that of the pseudopodal rays mainly has its origin. In the peripheral layer of vesicles there are usually to be detected two contractile vesicles, situated at opposite poles of the body, as seen in figs. 1, 2, 3, ffl, &. At one moment they may exhibit no difference in appearance from the contiguous vesicles; but, from time to time, one or both may be seen slowly to enlarge, pressing on the surrounding vesicles, and rising as a clear hemispherical bubble above the surface of the body. See figs. 1-5, 7, a. On reaching the full degree of expansion, they rather abruptly col- lapse, and expel the liquid contents, causing a sinking of the wall of the vesicle, and producing a temporary concave depression on the surface of the body, as seen in figs. 1 , 2, &. The collapse of the vesicles is sufficiently strong to give a visible shock to the body of the animal. Shortly after the collapse, the contractile vesicle reappears in the same place. According to Stein, Carter, and other authorities, Actinosphcerium eich- hornii contains many nuclei, large individuals having a hundred or more. They occupy a position in the superficial part of the interior mass of vesi- cles, beneath the peripheral layer of larger ones, enveloped in the same kind of finely granular protoplasm. Ordinarily, they are invisible without the application of chemical veagents, or at most they are sometimes barely GENUS AOTmOSPH^EIUM— ACTINOSPH^EIUM EICHHOENII. 261 perceptible as pale, shaded spots in the interior of the body. Dilute acetic acid brings them into view as pale and faintly granular spheres, with a large central nucleolus, or several smaller nucleoli. The smallest individ- uals appear commonly to contain but a single nucleus, as in the common Sun-animalcule. The pseudopodal rays project in all directions (figs. 1-3) as in the latter, and are equally numerous. They are long, tapering extensions of granular protoplasm, sustained by a delicate axial thread, but proportion- ately are commonly not so long as in Adinophrys soh The axial thread of the pseudopodal rays is a. simple, comparatively rigid, and straight filament, which starts from the surface of the interior vesicular mass of the body, and passes through the peripheral layer of larger vesicles between them. The threads extend through the greater part of the length of the pseudopods, but do not reach their ends. A portion of the granular protoplasm of the pseudopods appears to originate from the stratum immediately beneath the peripheral layer of vesicles, and extends upon the axial thread through the latter, when it is reinforced by an additional portion converging from the exterior investment of the same material, as seen in fig. 7. The axial threads of the pseudopods are homogeneous, and appear to consist of more or less solidified protoplasm. They clearly contribute to sustain and strengthen the pseudopodal rays ; and, though they seem to be, they are not rigid spicules, for they may be seen to bend beneath the rude shock of active animalcules coming into contact with the rays. At times, also, they appear not to be persistent structures, as I have observed individuals in which they seemed to vanish with the retraction of the rays, and again reappear with the production of these. Occasionally I have seen individuals of Actinosphserium with few or no rays. The food of Actinosphcerium eichhornii in general is of the same nature, and the mode of taking it the same, as in Actinophrys sol. With its usually jgreater size and strength than in the latter, the former will feed upon larger and more powerful animals, especially various rotifers. Though the animal is to all appearances exceedingly inactive and sluggish, remaining sus- pended in the water almost motionless or feebly ghding about, it is a glut- tonous feeder and consumes a large amount of food. This commonly con- 262 FRESHWATER RHIZOPODS OF KORTH AMERICA. sists of ciliated and flagellated infusoria, rotifers, zoospores, diatoms, the smaller desmids, etc. Large active animalcules rudely brush against the multitudinous rays of Actinosphaerium, and turn them aside without apparent harm to either, and without the Actinosphaerium displaying any evident mark of irritability, either in its rays or body. Weaker animalcules, coming within the influence of the rays, are often rendered more or less powerless, or their movements become enfeebled and finally cease. Being gradually drawn toward the body by the retraction of one or more of the rays, the prey becomes im- mersed in a mass of projected protoplasm, as seen in figs. 1, 2, c, which is then gradually withdrawn with the included food. It passes through the peripheral layer of large vesicles, and sinks among the mass of smaller vesicles within. In the interior of the latter, food of various kinds is often visible. Comparatively soft food, when swallowed quickly, assumes the form of a ball, and is commonly seen in this condition, included within a drop of clear liquid, in the interior of the body. More consistent food, such • as diatoms or the hard parts of rotifers, retains the original form. The food is rapidly digested, undergoing changes, according to its nature, as in other Rhizopods, and as repeatedly indicated in the preceding pages. Excrementitious matter, usually in the form of a ball, is discharged, by a somewhat quick projection of a portion of the interior protoplasm of the body containing the ball, through the peripheral vesicular layer, as repre- sented in d, fig. 2. As above indicated, ActinospJi cerium eicMornii may appear with few or ijt) rays. Fig. 4 represents an individual, which, when first observed, possessed but a single long ray. Afteir a brief interval, a second, and then a third, were projected, and after an hour had elapsed it presented many rays directed from all parts of the surface of the body. I once met with a singular body, of vesicular constitution and rayless, as represented in fig. 6, which I supposed to be a rayless form of Actino- sphcerium eichhornii. It was irregularly oval, and about 0.4 mm. long. The peripheral vesicles were less uniform than in the characteristic forms of Actinosphaerium, and had their greater diameter mostly in a reverse direction from the usual one. Though entirely rayless, the animal showed some activity, displayed in feeble changes in the outline of shape, and in the slow expansion and quick collapse of some of the larger vesicles of the GEMJS AOTINOSPH.EEIUM— AOTINOSPH^EIUM EICHHOENII. 263 exterior layer. It contained several articles of food, among which were conspicuously seen a diatom and a large rotifer. After twenty-ftur hours all the food was expelled except one green alga, and the animal had assumed a globular form, 0.28 mm. in diameter. No rays appeared, and later the animal died. In several instances I have observed bodies, as represented in figs. 11, 12, which possessed the shape, size, and apparent vesicular constitution of ActinosphcBriwm eichhornii, but they were lifeless, and the vesicles were composed of structureless membrane, without a trace of interior or exterior liquid protoplasm. Whether these bodies really have any relationship with Actinosphaerium, or whether they pertain to some other animal, I have not beeii able to determine. Found in the same localities in which I had, at an earlier season of the year, observed many active individuals of Actino- sphaerium, I have suspected that they might be of the nature of an exuvium, . discharged in some way by the latter. Another enigmatic body occasionally met with, as represented iri figs. 9, 10, I have suspected to be a fragment of an Actinosphserium. In this particular specimen, of which two views are given, the body consisted of a globule of granular protoplasm, containing at first two vesicles, and then, by union of these, a single larger vesicle, and a single, pseudopodal ray sustained by an axial thread. Another specimen, represented in fig. 8, consisted of a globule of gran- ular protoplasm, proportionately more abundant than usual, together with a number of included vesicles of variable sizes. From the body there pro- jected four long, delicate rays, upon each of which there was a large drop of protoplasm. I am uncertain whether the specimen had any relationship with Actinosphserium. Admosphcarmm eichhornii exhibits a considerable range of size. Ordi- narily, spherical individuals are from 0.1G6 mm. to 0.33 mm. in diameter, with'the rays usually of less length than the diameter of the body, and commonly from 0.1 mm. to 0.2 mm. long. Oval individuals reach 0.66 mm. in length. ActinosphBTiwm eichhornii is found in the same kind of localities as Actinophnjs sol, and in association with it. ' Its favorite resort is quiet water among duckmeat; hornwort, etc. It commonly appears nearly stationary, or as if gently floated along by an imperceptible current of the water. It 264 FEESH- WATER EHIZOPODS OP NORTH AMERICA. at times shows slight changes in the outline, while its contractile vesicles pursue their usual rhythmical movements, at each moment as one collapses giving the whole body a gentle quiver. ACANTHOOYSTIS. Greet, alcantha, a tliom ; TcmsUs, a cyst. Trichoda ; Sohrank, 1803. Aetinophrys : Elirenberg, 1833. AcantTiocyiiis : Carter, 1864. Animal Actinophrys-like in general appearance. Body spherical, soft, composed of finely granular protoplasm mingled with variable proportions of bright-green and colorless corpuscles, the former at times absent, also containing diffused oil molecules, a central nucleus, together with vacuoles, and a variety of food materials commonly in the form of balls. Exterior of the body invested with numerous delicate, silicious rays, implanted by minute basal disks, and ending in a simple, pointed or furcate extremity ; also giving off numerous delicate, soft rays like those of Aetinophrys ; fur- ther enveloped by a layer of protoplasm, rising in pointed processes on the rays, and pervaded by a multitude of exceedingly minute, linear particles; the enveloping layer sometimes absent. ACANTHOCYSTIS CH^TOPHORA. Plate XLIII, figs. 1-6. Tn^hoda chwtophora. Schrank : Fauna Boica, iii, 2, 1803, 93. Aetinophrys viridia. Ehrenberg : Abh. Ak. Wis. Berlin, 1833, 228 ; Infusiousthierchen, 1838, 304, Taf. xxxi. Fig. Til. — DujarfUu : Infusoires, 1841, 267. — Perty : Kennt. kleinst. Lebensformen, 1852, 159. — Pritohard : Hist. Infus. 1861, 560. — Micrographic Dictionary, pi. 23, fig. 6. Aeanthocystis turfacea. Carter : An. Mag. Nat. Hist. 1864, xiii, 36, pi. ii, fig. 25. — Archer : Quart. Jour. Mic. Sc. X, 1870, 27; xvi, 1876, 361.— Hertwig and Lesser: Arch. mik. Anat.x, 1874, Suppl. 204.— Greeff : Arch. mik. Anat. xi, 1875, SO, Taf. i. Fig. 1-4. Aeanthocystis virkUs. Greeff: Arch. mik. Anat. v, 1869, 481, Taf. xxvi. Fig. 8-17.— Greenachcr : Zeits. wis. Zool. xix, 1869, 289, Taf. xxiv, Fig. 1-3.— Schneider : Ibidem, xxi, 1871, 505.— Leidy: Proc. Ac. Nat. Sc. 1874, 166. Aeanthocystis pallida. Greeif: Arch. mik. Anat. v, 1869, 489, Taf. xxvii. Fig. 19. Aeanthocystis (vindis) turfacea. Greeif: Arch. mik. Anat. xi, 1875, 3, Taf. i. Fig. 1-4. Body spherical, usually bright green from the presence of chlorophyl corpuscles, mingled in variable proportion together with colorless ones; sometimes colorless from the absence of the former. Nucleus central, com- monly obscured from view by the surrounding constituents. Silicious or spinous rays of two kinds : the one long, comparatively strong and acutely furcate at the free end ; the other short, very delicate, and widely furcate at the free end, and sometimes altogether absent. Soft rays simple, granular. GENUS ACANTHOCYSTIS— ACANTHOCYSTIS CH^TOPHOEA. 265 as long as or longer than the spinous rays. Exterior envelope of the body appearing as an atmosphere of exceedingly minute bacterium-like particles, which are sometimes absent. Size. — Diameter of the body ranging from 0.048 mm. to 0.1 mm. ; length of the larger furcate spines from 0.02 mm. to 0.06 mm. ; length of the soft or pseudopodal rays about equal to the diameter of the body or longer. Locality. — In the same positions as Adinophrys sol and ActinosphcBrium eichhornii, in quiet waters, among various aquatic plants. Observed in the vicinity of Philadelphia and other places in Pennsylvania, in New Jersey, Ehode Island, Colorado, Wyoming Territory, and Nova Scotia. Found in ponds in the Uinta Mountains of Wyoming Territory, at an elevation of 10,000 feet. AcaBithocysti«$ chsetophora, as ordinarily observed under moderate powers of the microscope, resembles the common Sun-animalcule, but with the body of a bright-green color, hence its familiar name of the Green Sun-animalcule. Under high powers of the instrument it is seen to possess a more complex structure, as represented in fig 1, pi. XLIII The body of Acanthocystis chcetophora is spherical, and is composed of a basis of finely granular protoplasm, with scattered oil molecules, and variable proportions of globular corpuscles, mostly of nearly uniform size. A clearer central spot indicates the presence of a large nucleus, which may be brought into view by the action of reagents. The corpuscles mentioned are commonly for the most part, if not entirely, of a bright-green color, and accord with the characters of cliloro- phyl. They are often very numerous, and appear especially to be con- fined to the more superficial portion of the protoplasmic mass of the body. Often mingled Avith them there are variable proportions of clear, colorless corpuscles, of about the same size, and occasionally individuals are to be found, as represented in fig. 4, in which these exist to the entire exclusion of green ones. Among the green and colorless corpuscles, from time to time, other globular bodies exist, of variable sizes, some of which are distinguishable as food-balls and vacuoles. Distinct contractile vesicles I have never been able to detect. 26G FEESH-WATEE EHIZOPODS OF NOETH AMEBIC A. A central nucleus brought into view in an individual, by the action of an ammoniacal solution of carmine, was finely granular, and about 0.0238 mm. in diameter. The exterior of the body of Acanthocystis clKBtophora is profusely invested with exceedingly delicate spinous rays, which are straight and rigid, and remind one of minute acicular crystals emanating from a nuclear centre. In strong, reflected light, these rays appear glistening white, and they are silicious in composition. They are attaclied to the surface of the body by little disks, which give to it a minutely mammillated appearance, and are sufficiently numerous to form a complete scale-like armor to the animal. The ray spines are of two kinds : a longer, stouter form, terminating in an acutely notched extremity (figs. 1, 2), and a shorter and more delicate form, with a wide, furcate extremity (fig. 3). The longer, stouter spines exhibit a dark axial line, apparently indicating a tubular condition. In some individuals, the shorter and more delicate spines are absent. The pseudopodal rays of Acanthocystis chcetopJiora are numerous, and of the same character as those of Actlnophrys sol. Commonly, they are difficult to distinguish among the forest of spinous rays, excepting where they project beyond these. » Commonly, the body of Acanthocystis chcetopJiora is invested with a thick layer of protoplasm, distinguished chiefly from its being densely pervaded by exceedingly minute, linear particles, which remind one of an atmosphere of bacteria enveloping the animal. Usually, this dust-like stratum includes completely the smaller furcate rays, and ascends in pointed processes upon the longer ones to a variable extent. Sometimes the exterior stratum, with its bacteria-like particles, is completely absent. Commonly, the body of Acanthocystis chcetophora is abput 0.0833 mm. in diameter. The longer furcate spines measure about 0.1 mm. in length, and appear as fine as the micronietric lines themselves. The smaller spines are from a fifth to a third the length of the others, and much more delicate. Acanthocystis chcetophora occurs in the same localities as the ordinary Sun-animalcule, and, though frequent, is not so common as the latter. It likewise has nearly similar habits. At times it appears t-o remain quite stationary, but mostly exhibits a slow gliding motion, and apparently so passive that it seems to be induced by a feeble current of the medium in GENUS ACAl^THOOYSTIS-ACANTHOCYSTIS CH^TOPHOEA. 267 which it hves. The movement is, however, clearly active, as proved by the fact that equally light objects in the vicinity remain quiescent. Acanthocystis chcBtophora feeds on the smaller algge and animalcules, which are captured in the same manner as with Actinophrys sol. In the gradual approach of food, through the dense forest of rays investing the body, the armor formed by the basal disks of the spines rises in a conical eminence, and opens outwardly so as to allow of the entrance of the food. In the process, a portion of projected protoplasm receives the latter, and the whole together is withdrawn, when the body resumes its regular spheroidal form. In the act of discharging excrement, a similar process occurs, the armor at some point opening outwardly, so as to give passage to the expelled ■ matter. In the movements of the animal, at times slight changes in shape become obvious, from a spheroidal to a more ovoidal and polyhedral out- line. The rays and spines, though ordinarily regularly divergent, may occasionally be seen, at some part of the body, to become more or less convergent, or to a greater degree divergent. I think there can be little doubt that. Acanthocystis chcetopJiora is the same animal as the one described by Ehrenberg under the name of Actino- phrys viridis This, however, appears to have been previously described by Schrank, with the name of Trichoda chcetophora, and the original de- scription applies so well to the creature in question, that, according to the rules of zoological nomenclature, I have adopted for it the earlier specific name.* Ehrenberg himself remarks, in reference to his description of Actinophrys viridis, that he had overlooked Schrank's form, which may probably be the same, and in which case his specific name should be prefeiTed.f I have commonly observed Acanthocystis chcetophora of a bright-green color, dependent on variable proportions of chlorophyl corpuscles, as seen in fig. 1. Rarely, I have met with the same form in all respects alike, excepting in being devoid of the bright-green color, as represented in fig. 4. This colorless form has been described by Professor Greeif under the name * The original description is as follows: "Kugelformig, grtin, nach alien Eiohtungen gestralt. Allenthalben ziemlioh dicht mit crystallhellen Haaren besetzt. Bewegnng langsam fortschreitend, . ohne alle Bewegnng der Haare." t lufnsionstliiercTien, 304. 268 FEESH-WATEE RHIZOPODS OF NOETH AMEEIOA. of Acanthocystis pallida. Mr. Archer* regards it as an accidental colorless form of Acanthocystis turfacea Probably it is one of the stages of life through which the ordinarj^ green-colored animal may have to pass. In one instance I observed a colorless individual of A. ch, 116. tAnuals and Magazine of Natural History, 1863, 458. 280 PEESH-WATEE EHIZOPODS OF NOETH AMERICA. motion. Not unfrequently spindle-like accumulations of protoplasm occur in the course of the pseudopodal threads. Sometimes, through the conjunc- tion and spreading of several of the latter together, islet-like expansions occur, and become the centres of secondary nets. The pseudopodal extensions of Gromia consist of pale granular proto- plasm with coarser and more defined granules. The latter are observed to be in incessant motion along the course of the threads, flowing in opposite directions in all except those of the greatest delicacy. See iig. 4. In the larger threads, the granules are immersed and near together; in the smallest threads, they are in single rows, more or less widely separated, and thicker than the threads, so that these appear like strings of minute beads. In the flow of the granules in the pseudopodal threads, they are some- times seen to slacken their speed, or for a moment become stationary, and then reverse their course. Grranules arriving at a dividing branch are sometimes retarded, and then take one or another direction; or, passing from one main branch to another through a by-path, they may take a reverse course from their former one. The movements of the granules, though apparently independent, are rather due to the currents or flow of the protoplasm constituting the basis of the pseudopodal threads. Besides the gi-anules, minute vacuoles often make their appearance along the course of the pseudopods. Some of these seem to be of the character of contractile vesicles, — starting as mere points, slowly enlarging, and then collapsing. Other circular spots in the pseudopodal threads, or in patches fonned by upion and anastomosis of the latter, appear as mere circular spaces, due to spreading of the protoplasm in the meshes of the net. Occasionally, minute diatoms and other objects which come within the territory of the pseudopodal net of Gromia terricola are seen to become immersed in the substance of the threads, and to move along in a manner reminding one of a boat carried along in the current of a river. Gromia terricola, by means of its pseudopodal net, was observed to be strongly disposed to accumulate around it a quantity of dirt, and especially at the posterior part of the body, as seen in fig. ] . In one individual, after completely surrounding itself with sand and dirt, it entirely withdrew its pseudopodal rays, and nothing that was done could induce the animal again to protrude them. GENUS BIOMYXA— BIOMYXA VAGANS. 281 Commonly, the specimens under observation remained nearlj'- stationary in position, but occasionally the body appeared to be dragged along with extreme slowness through aid of the anterior pseudopodal extensions. BIOMYXA. Greek, iios, life; muxa, mucus. Initial form spherical, but incessantly changing, consisting of a glairy, colorless, finely granular protoplasm, which has the power of expanding and extending itself in any direction, and of projecting pseudopodal fila- ments, which freely branch and anastomose; a circulation of minute granules in currents along the body and pseudopods ; contractile vesicles numerous and minute, and occurring both in the body and pseudopods. A nucleus present or absent. BIOMYXA VAGANS. Plates XLVII, figs. 5-12 ; XLVIII. Biomyxa vags,ns. Leidy : Proc. Ac. Nat. Sc. Phila. 1875, 124. Body at rest, spheroidal, oval, or botuliform ; in motion, of ever chang- ing form, — centrally spheroidal, or elliptical, discoid, cylindroid, fusiform, triangular, quadrate, band-like, or dividing into several portions, — with pseu- dopodal prolongations, usually as filaments, mostly bipolar, of very variable form and length, branching and anastomosing so as to produce more or less intricate nets, often expanding into perforated patches. Composed of pale granular protoplasm with oil molecules, and numerous minute contractile vesicles appearing at the surface of the body and along the pseudopodal extensions. Nucleus when present large, distinct, clear or faintly granular. Vacuoles few or none. Sise. — Exceedingly variable. Locality. — Sphagnous swamps, in bog- water. New Jersey and Penn- sylvania. In the Proceedings of the Academy of Natural Sciences of Philadel- phia for April, 1875, I published a brief notice of a curious organism, under the name of Biomyxa vagans. I first discovered it in water with aquatic plants and sphagnum, from the border of Absecom pond, New Jersey, collected in the autumn and preserved in the house during the winter. The same thing I again found in sphagnum, obtained the follow^. 282 FEBSH-WATEE EHIZOPODS OF NOETH AMEEICA. ing August, in the same locality, and in September, on Broad Mountain, Schuylkill County, Pennsylvania. Subsequently I observed specimens collected with sphagnum at Kirkwood station on the Camden and Atlantic 1 ail way. ISiomyxa vag^ans, as represented in figs. 5-12, pi. XL VII, and pi. XLVin, is a colorless body <^t" ever changing and most variable form, consisting of a glairy, colorless, finely granular protoplasm. From a usually more or less central mass or body it spreads itself into a sheet of irregular form, giving off pseudopodal extensions, which branch and anas- tomose with one another. Biomyxa moves slowly, incessantly, and evenly, and never for a moment remains the same. The body mass of protoplasm composing it may spread more or less uniformly from the initial spheroidal form, or it may spread unequally, or divide and extend in any direction. Frequently it becomes narrowly extended at one or both poles, becoming more and more elongated into a cord, which may expand into a band, or may divide and extend into several divergent cords or bands. The whole or different portions may expand and become very thin, even to such a degree as to break into fissures and circular holes. The pseudopods appear as long, tapering extensions of the body proto- plasm, often forking, and with the terminal branches as exceedingly delicate filaments. Contiguous branches frequently anastomose and form nets, which here and there, by expansion, assume the aspect of thin patches with circular holes. The pseudopods are quickly produced, and as quickly modified or withdrawn. A circulation of granules takes place along the course of the pseudo- podal extensions of Biomyxa as in Gromia. It occurs both outwardly and inwardly at the same time in the trunks and larger branches, bvit in one direction only in the finest. In the flow, frequent fusiform accumulations of protoplasm are produced along the pseudopodal extensions, and these sometimes expand into patches or become secondary centres for the emana- tion of pseudopodal filaments. In Biomyxa there is not the slightest distinction between endosarc and eclosarc, the whole structure being a homogeneous, pale and finely granular protoplasm, with variable proportions of minute oil molecules, with fewer, GENUS BIOMYXA— BIOMYXA VAGANS. 283 large, darkly defined granules, probably also oil-like in character. It con- tains numerous minute contractile vesicles, commonly ranging from 0.002 mm. to double that size, and rarely reaching quadruple the same. They are usually best seen and readily recognized by their characteristic move- ments — slow enlargement, sudden collapse, and reappearance — along the borders of the body and in the forks and nodal expansions of the pseudo- pods. Rarely distinct vacuoles, independently of the contractile vesicles, and much larger, are to be seen within the body mass of Biomyxa The round holes which are often produced by the expansion and rupture of portions of the protoplasm or by the closure of meshes in pseudopodal nets are to be distinguished from the true vacuoles. Biomyxa vagans occurs of very variable size, and sometimes appears so devoid of a definite centre, and without nucleus or other conspicuous element, that I have supposed it was perhaps nothing more than a detached fragment of Gromia. It has also been a question with me whether to regard it as a true rhizopod or whether to view it as the plasmodium of a fungus.* In structure and habit, so far as observed, it seems to accord with the latter rather than with, the former, though I have not detected a coalescence of individuals in Biomyxa. Cienkowskif has described several organisms, related with the latter, of which- he regards one as a 'fresh- water plasmodium,' while the others are viewed as Rhizopods, under the names of Vampyrella vorax and AracJt- nula impatiens. The character of Vampyrella has already been given; the diagnosis of Arachnula is as follows: body naked, colorless, without nuclei, with one or more contractile vacuoles; pseudopods but little branched, sometimes anastomosing, usually springing by thick cords from any part of the surface of the body.J In the same memoir, under the head of Naked Rhizopods, Cienkowski »The researches of Bary, Cienkowski, and others show that the spores of the little fungi of the family J^Ies enut, flagellate cellules', which subsequently lose the flagellum and assume the lamuy mji» j,^ h continued growth and coalescence, a number of the amoe- :r :ru?estrr rr Lt^^^^^^^ 4r O. ..otoplasm. retaining "s ^^^^ P^^er- and named ' plasmodium' by Cienkowski. The plasmodium Anally produces the spore-bear.ng fungus. t Archiv f. mikros. Anatomic, 1.5, 1876. t Ibidem, 27. 284 FEESH-WATER RHIZOPODS OP NORTH AMERICA. describes a form with the name of Gymnophrys cometa, * Avhich resembles Biomyxa, as represented in fig. 12, pi. XL VII, and figs. 7-9, 13, 14, pi. XLVIII. The former, however, differs in having no contractile vesicles. In this respect, hkewise, Biomyxa differs from the nearly related Leptophrys of Hertwig and Lesser.f 'As represented in fig. 6, pi. XLVIII, Biomyxa closely resembles the Amoeba porreda of Schultze, J from the Adriatic One of the earhest observed specimens of Biomyxa vagans, represented in fig. 1, pi. XLVIII, occupied, as first seen, a nearly semicircular space, about 0.6 mm. by 0.4 mm. The main protoplasmic mass extended from a common base in three bands, of which the intermediate one was longest and tapering as it was resolved into divergent pseudopodal branches; while the lateral bands expanded outwardly, and presented large circular holes previous to branching. The pseudopodal extensions freely anastomosed with one another. Small contractile vesicles appeared in many places, both in the principal bands and in the pseudopods. The median band and base contained mtmerous minute fusiform desmids, all of the same kind. The protoplasm of the main bands exhibited a faintly striate appear- ance, perhaps due to an arrangement of granules occasioned by currents. Circulation was observed in different directions at the same time, as indi- cated by the arrows in the figure. The organism gradually changed its shape, becoming a single band, then a central elliptical disk, etc. Large angular spaces included in the anastomosis of the pseudopodal extensions would slowly diminish, assume a circular form, and continue to decrease until they seemed to be vacuoles, or in their final closure as if they were contractile vesicles. The pseudopodal filaments were rather quickly projected, and sometimes as quickly con- tracted and entirely withdrawn. Occasionally they would appear tortuous, or would be seen with a slow, waving, or feeble, lashing movement. Circulation, indicated by the motion of the granules, occurred along the course of the pseudopods, often in a reverse direction on the two sides * Ibidem, 31. In an excellent oompilatiou of "Kecent Contributions to oirr Knowledge of Fresh- water EMzopods," published in the Quarterly Journal of Microscopic Science, 1877, 349, Mr. Archer expresses an opinion in regard to Gymnophrys which accords with an early impression of my own in relation to Biomyxa. He remarks "that the figures of this Sarcodino remind one not a little of a portion of the mass of a Gromia become isolated and detached by some readily concoivable force, having wandered too far from the headquarters." t Ibidem, 07, 1874. t Ueber d. Organismus d. Polythalamien, 1854, 8, Taf. vii. Fig. 8. GENUS BIOMYXA— BIOMYXA YAGANS. 285 of the same filament. Feeble movements, circulatory as well as contractile and expansile, were also seen in the body mass of the creature. Preserved until the following day, it presented no essential change, excepting that it had completely discharged all the desmids previously noticed. In the same drop of water containing the individual just described there was a very much smaller one, which I supposed might be a fragment of the former. When detected, it presented an elliptical body prolonged into pseia- dopodal extensions at the opposite poles, as seen in fig. 2, and after a little the body appeared to run along one of the pseudopodal extensions to the end, like a drop of water flowing upon a string, when the creature assumed the shape seen in fig, 3. From the side of the body, in the latter condi- tion, there projected a delicate pseudopod, which was noticed to vibrate slowly toward the main one. The successive changes of shape of Biomyxa are sufficiently rapid often to render it difficult to delineate the exact forms. Figs. 5 and 6, pi. ■ XLVII, represent two such changes in one individual, and figs. 7-9 three changes in another individual. Fig. 10 represents a third individual accompanying the preceding. The arrows indicate the general direction in the circulation of the granules. Figs. 4-6, pi. XL VIII, represent suc- cessive changes of another individual. As first seen, it was regarded as a minute worm casting; but after a moment its movements and extension of pseudopods indicated its true character. The material containing the specimens above described, consisting mainly of sphagnum, was collected from the edge of Absecom pond, New Jerse}^, in September, 1874, and was preserved in a glass-covered case during the winter. The Biomyxas were noticed in association with a multitude of minute, bright-green, one-celled algae, in a transparent jelly attached to the side of the glass case contiguous to the sphagnum covering the bottom of the latter. At no time had I the opportunity of observing Biomyxa take food of any kind, and rarely have I noticed food within the animal. On one occa- sion I saw an individual which attracted my attention from its having entangled in its pseudopodal net two active, green Euglenias. These were watched with much interest, under the impression that they had been cap- tured as food; but, after much wriggling, they botli disengaged themselves, and escaped. 286 FEESH-WATEE EHIZOPODS OF NOETH AMBEICA. Fig. 12, pi. XLVII, and figs. 7-9, pi. XLVIII, represent four views of an individual, exhibiting the chief successive forms assumed in the course of an hour. The specimen was obtained, with others of the same character, in wet sphagnum, from the cedar swamp of Absecom, collected in August, 1876. Organisms exactly of a like character to those above described I also obtained in sphagnum collected on Broad Mountain, Schuylkill County, Pennsylvania, in September, 1876. Figs. 10-14, pi. XLVIII, and fig. 11, pi. XLVII, represent six successive changes of an individual of the kind, as observed during one hour and twenty minutes. None of the specimens above described or indicated contained any trace of a nucleus, and my impression of Biomyxa, as derived from the observation of these, was that it would form a member of the order of Monera, notwithstanding its possession of contractile vesicles, which are also considered as being absent in the latter. In April, 1877, in material from a sphagnous swamp near Kirkwood station on the Camden and Atlantic railway, I found an organism agreeing with the former in all respects, except that it contained a distinct nucleus. This was globular and distinctl}^ and uniformly granular. An individual of the kind, exhibiting three successive changes of form, is represented in figs. 18-20, pi. XLVIII. With the nucleated specimens, others were detected without nuclei, mostly smaller, and looking as if they might be fragments of the former. Three successive views of an individual of this character are represented in figs. 15-17. Nearly at the same date with the last observations, and under circum- stances almost exactly similar to those in which I originally discovered Biomyxa vagans, I found an organism which I have supposed to be the nucleated form or condition of the latter. It was detected in a clear jelly, among numerous minute desmids, some of which were crescentoid and others straight and fusiform. The creature, of which a number of examples were noticed, appeared in general of a more compact or less translucent character than Biomyxa as commonly seen, and though of very changeable form appeared less disposed to produce those extreme changes observed in the latter. Fig. 21, pi. XLVIII, represents an individual of the kind, and figs. 22-25 represent four successive changes of form of a second indi- vidual. The body was composed of colorless granular protoplasm, with GENUS BIOMYXA— BIOMYXA YAGANS. 287 numerous, scattered, darkly defined granules. The nucleus was large,, globular, and clear, and contained a nucleolus. Mostly, it was central, though frequently displaced from this position in the successive changes of shape of the body. Several contractile vesicles occupied the borders of the latter, exhibiting the usual characteristic movements. None of the specimens contained distinct food, though occasionally colorless vacuoles, apparently different from the contractile vesicles-, were observed among the contents. An individual, shortly after 'being noticed, was seen to discharge a. large oval mass with granules, as represented iij fig 22. LISTS OF FRESH-WATER RHIZOPODS, INDICATING THE MANY FORMS WHICH OCCUR TOGETHER IN CERTAIN LOCALITIES. I. LIST OF RHIZOPODS OBSEEVED IN THE SEDIMENT OP WATER SQUEEZED INTO A WATCH CRYSTAL PROM A SMALL BUNCH OP SPHAGNUM COLLECTED IN THE CEDAR SWAMP IN THE VICIN- ITY OF MALAGA, GLOUCESTER COUNTY, NEW JERSEY, JUNE 6, 1879. 1. DrpPLtFGiA PTEiFOBMis. Forms like those of figs. 14, 23-25, pi. x. Frequent. 2. D. ACUMINATA. Lite those of figs. 23-26, pi. xiii. Frequent. 3. D. CONSTEICTA. Like those of figs. 5-7, 37-44, pi. xviii. Frequent. 4. D. GLOBTJLOSA. Small forms ; numerous. 5. D. AECULA. Pigs. 34^37, pi. xv. Occasional. 6. D. SPIRALIS. Pew. 7. Nebela coLLARis. Many Varieties. Plask-Uke forms, with neck of variable length; length 0.06 mm. to 0.066 mm. ; greater breadth 0.027 mm. to 0.036 mm. Broader pyriform kind, with less weU defined neck: length 0.072 mm. to 0.132 mm.; greater breadth 0.042 mm. to 0.09 mm. "Variety N. Mnodis, as in figs. 1-7, pi. xxii: length 0.12 mm.; greater breadth 0.054 mm. Varieties with the shell merging in structure into that of Difflngia, composed of irregularly angular and rod-like plates, or variable proportions of these with diatoms and fragments of the same, or with round or oval disks : sizes ranging from 0.09 mm. to 0.15 mm. in length by 0.084 mm. to 0.12 mm. in greater breadth. Variety N. retorta, a peculiar form for the first time observed; a single specimen as represented in the woodcut on page 151; shell retort-form, or resembhng in shape that of Gyphoderia ampulla, but in structure characteristic of Nebela, being composed of circular disks of variable size: length 0.144 mm.; greater breadth 0.072 mm.; less breadth 0.036 mm.; greater breadth of mouth 0.027 mm. 8. N. FLABELLULUM. Length 0.09 mm.; greater breadth 0.096 mm. Comparatively few. 9. N. BAEBATA. Occasional. 10. N. ANSATA. Shell composed of circular disks. Length 0.21 mm. to 0.24 mm. ; greater breadth at fandus 0.102 mm. to 0.108 mm.; between ends of processes 0.132 mm. to 0.144 mm. Few. II. N. OAEINATA. Length 0.216 mm. to 0.228 mm.; greater breadth 0.156 mm.; depth of keel 0.018 mm. Rare. 12. N, CAUBATA. As in figs. 22-24, pi. xxvi. Rare. 19 EHIZ ^^ 290 FEESH-WATEE EHIZOPODS OP NOETH AMEEIOA. 13. Arcella vulgaris. Varieties with both evenly convex and mammillated fundus. Occasional. 14. A. DiscoiDES. Frequent, and of varied sizes. 15. A. MITEATA. Eare. 16. Heleopeea picta. Frequent. 17. H. PETEicoLA. Occasional, but more frequent than usually. In some the shell was incorporated with sand the greater part of its extent. 18. QuADKULA SYMMETRICA. Occasional. 19. Centeopyxis ACULEATA. Frequent and varied. Variety C ecornis grading by intermediate ones into Diffiugia constricta. Frequent. 20. Htalosphenia papilio. Frequent, but not so abundant as commonly observed in sphagnum from similar localities. 21. H. ELKGAws. Frequent. 22. EuGLTPHA CILIATA. Generally small, and very variable in size; larger ones occasionally devoid of cUs. Large empty shells with twelve blunt, thickened denticles to the mouth; plates of the shell distinctly hexahedral and in close juxtaposition, with no signs of being oval and overlapping at the contiguous borders. Variety E. strigosa. Abundant. 23. E. OEiSTATA. Frequent. A small individual with four conspicuously thickened denticles to the mouth of the shell was 0.054 mm. long, 0.018 mm. broad, and 0.009 mm. at the mouth. 24. E. BEACHIATA. Occasional. Two empty shells adhered at the mouth, as if when alive the animals had been in conjugation. The shells had each six acute denticles to the mouth, the plates of which were not perceptibly thicker than elsewhere. The plates generally were nearly round, and overlapped at the contiguous borders, so as to include hexahedral spaces. One shell was pro- vided with a pair of lateral hair-like spines as usual, but the other shell was spineless. Size of the spinous shell 0.108 mm. long, 0.036 mm. broad, and 0.0135 mm. at the mouth ; of the spineless shell 0.102 mm. long, 0.036 mm. broad, and 0.012 mm. at the mouth. 25. E. MUCEONATA. Occasional. Several without the mucro, but otherwise the same. 26. AssuLiNA SEMiNULTJM. Frequent. Several large and uncolored observed besides the ordinary brown variety. 27. Sphenodeeia LENTA, itrequcnt. Observed several with the border of the mouth minutfely but feebly denticulate. 28. S. maceolepis. Frequent. A species for the first time observed, with characters as foUows: small, compressed pyriform, with the neck gradually prolonged from the body. The latter with a pair of wide hexagonal plates across the intermedi- ate portion of the broader sides of the shell. Length 0.036 mm. ; breadth 0.024 mm.; width of mouth 0.012 mm. See woodcut, page 232. 29. CYPHODEEIA JiMPULLA. FcW. 30. Teinema enchelys. Numerous and of many varieties. Several bright brown shells, like those of Arcella, for the first time observed. 31. Placooista spinosa. Eare. 32. PsEUDODiPFLTJGiA GEACiLis. Like fig. 21, pi. xxxiii. Length 0.045 mm. ; breadth 0.03 mm., and at mouth 0.018 mm. Occasional. 33. Olatheulina elbgans. Dead shells, or individuals in the quiescent state. One observed in the latter condition containing five nucleated balls, 0.009 mm. in diameter. Occasional. LISTS OF FEESH- WATER EHIZOPODS. 291. 34. Htalolampe penesteata. All rayless individuals. Occasional. 35. AoANTHOCYSTisI With delicate, simple, unforked spincs. Occasional. 36. Amphizonella violacea ? A single individual; for the first time observed. In the spheroidal form about 0.15 mm. diameter; endosarc of a deep violet hue; ectosarc colorless. Animal remained nearly stationary in position, with slight changes of form, and emitted from one to three digitate pseudopods, sometimes blunt, sometimes pointed, even or irregular, clear, and colorless at the periphery and ends, but violet internally at the base. 37. Amceba radiosa. Occasional. 38. A. PROTEUS ? Occasional. With the Rhizopods there were associated a multitude of desmids — Micrasterias, Euastram, Docidium, Closterium, etc , diatoms, etc., etc. II. EHIZOPODS OBSEEVED IN MATEEIALS COLLECTED EST THE TEAP EEGION OF EOCK HILL, BUCKS COUNTY, PENNSYLVANIA, JUNE 27, 1879. a. From sediment of a ditch traversing a meadow in which grew Spatter-dock, Nuphar advena. 1. DrppiiTJGiA GLOBITLOSA. Ovoid variety, with the narrower pole truncated by the circular mouth, which sometimes has a short, straight, or a slightly everted rim. Shell composed of fine quartz-sand or of chitinold membrane incorporated with thin angular plates of quartz. Endosarc colorless. Length 0.09 mm.; breadth 0.06 mm. ; width of mouth 0.024 mm. Frequent. 2. D. PTRiFOEMis. Ordinary forms, mostly small. SheU of quartz-sand. Endosarc in some green, in others colorless. Frequent. 3. D. aoumuntata. Shell of chitinoid membrane incorporated with variable propor- tions of thin angular plates of quartz-sand. Few. 4. D. LOBOSTOMA. Shell nearly spherical or oval, composed of angular quartz-sand; mouth trilobate, sometimes with a short and slightly reflected rim. Endosarc greeii. Frequent. Variety with smoky-colored shell, composed of fine angular sand, in shape spheroidal, oval or ovoid, and even, or mammiUary, like D. tuber- eulata, WaUich; mouth six-lobed, with or without a narrow projecting rim. .Length 0.132 mm. ; breadth 0.12 mm.; width of mouth 0.036 mm. Frequent. Variety with shell of chitinoid membrane incorporated with variable proportions of thin angular plates of quartz; endosarc colorless. Few. 5. D. CONSTRIOTA. Of varied sizes and proportions ; yellow and colorless shells of qnartzsand. Frequent. 6. D. SPIRALIS. Characteristic specimens with shell of quartz-sand. Occasional. 7. Cbwteoptxis ACULEATA. Abundant, of considerable variety, large and small, mostly yellow or brown, and generally having the chitinoid shell Incorporated with much sand. Variety C. ecornis. Frequent and merging into Difflvgia con- stricta. 8. Arcella vulgaris. Shell with even, convex, and with mammillated or cupped fundus. Frequent. 292 FEESH-WATEE EHIZOPODS OF NOETH AMEEIOA. 9. Aroella. One specimen observed with transversely oval shell 0.1 mm. long, 0.072 mm. broad, and 0.036 mm. high, with mouth 0.045 mm. in the long and 0.024 mm. in the short diameter. Even convex fundus and of bright burnt- sienna color. Animal active. 10. Nebela collaris. iN'arrow form with the cancellated structure of the shell obscurely developed. Eare. 11. Trinema bnohelys. Abundant, and of varied size and development. 12. Ctphoderia am3?ulla. Well developed and active ; shells yellowish and color- less. Frequent. 13. EuGLTPHA ALYEOLATA. Small Spineless forms, of variable sizes and proportions, and with 4, 6, and 8 teeth to the mouth. Frequent. 14. BuGLTPHA CILIATA. With and without lateral hairs. 15. PsETJDODiFFLUGiA GRACILIS. Oval form. Occasional. h. Contiguous to the ditch, from which the former were obtained, in the same meadow, there grew an unusual profusion of Selaginella apus. Por- tions of the plant, with earth adherent to the roots, on being moistened and squeezed, gave a sediment, which, besides many bright active diatoms, des- mids, etc., yielded the following Rhizopods : 1. DiFFLUGiA GLOBULOSA. Shell oval or ovoid, even, colorless or yellowish, com- posed of chitinoid membrane incorporated with variable proportions of thin, irregular, angular plates of quartz, or composed of small sand particles. Mouth truncating the narrower pole, circular, sometimes with a short, straight, or slightly everted rim. Endosarc colorless. Length 0.072 mm. to 0.09 mm.; breadth 0.036 mm. to 0.048 mm. ; width of mouth 0.018 mm. Frequent. 2. D. PYRiFOEMis. Small form ; shell of quartz-sand. Length 0.108 mm. to 0.156 mm. Not unfrequent. 3. D. CONSTRIOTA. Of varied proportions, colorless and yellowish, and merging into Gentropyxis ecornis. Frequent. 4. Qtjadeula symmetrica. Occasional. Length 0.072 mm.; breadth 0.036 mm. 5. Arcblla vulgaris. Living and active. Shell with cupped fundus. Occasional. 6. Trinema enchelts. Abundant and of varied sizes and proportions, and with varied degrees of obliquity. Eanging from 0.024 mm. to 0.096 mm. in length. A specimen constricted just above the position of the mouth was 0.96 mm. long, 0.042 mm. broad at the fundus, and 0.03 mm. wide opposite the mouth, which was 0.021 mm. wide. 7. EuGLYPHA ALVEOLATA. Small forms, spineless, with 4, 6, and 8 teeth to the mouth. From 0.03 mm. to 0.72 mm. long; 0.018 mm. to 0.036 mm. broad. Frequent. 8. E. CILIATA. Compressed forms, with lateral hairs, and 4- to 0-toothed. A speci- men observed with divergent hairs to the summit of the fundus in addition to the lateral ones. Its length 0.06 mm. ; breadth 0.03 mm. ; mouth 0.012 mm. ; nucleus 0.012 mm. Occasional. 9. Oyphoderia ampulla. Several dead shells. 10. Sphenodeeia LENTA. Common form. Occasional. Also a variety 8. dentata, with oval shell, composed of oval, overlapping plates ; neck short or obsolete ; mouth elliptical, oblique, with the border minutely denticulated. Length 0.054 mm. ; breadth 0.03 mm. ; width of mouth 0.012 mm. LISTS OF FRESH- WATER RHIZOPODS. 293 III. RHIZOPODS OBSERVED IN SLIME WITH MOSS AND ALG^ SCRAPED FROM THE VERTICAL FACE OF DRIPPING GNEISS ROCKS OP FAIRMOUNT RESERVOIR, PHILADELPHIA, JULY 6, 1879. 1. Depflugia oonsteiota. Occasional, and merging into forms which might be equally well viewed as the variety Centrojpyxis ecornis; 0.09 mm. long, 0.078 mm. broad, and with mouth 0.036 mm. wide. An unusually long specimen was 0.12 mm. long, 0.072 mm. in the greater and 0.054 mm. in the less breadth. When the mouth was on a level it stood 0.06 mm. high. AU specimens of a yellowish hue. 2. Centkopyxis aouleata. Small, of yellowish chitinoid membrane incorporated with sand, and usually with two or three spines. Length 0.072 nim. ; breadth 0.06 mm. ; width of mouth 0.03 mm. 3. EuGLYPHA ALTEOirATA. Small, spineless form ; abundant. Shell ovoid; trans- verse diameters uniform, rarely slightly compressed; fundus obtuse, rarely in the smallest acute ; mouth with 4, 6, or 8 teeth, the number not in accordance with size. More dead shells than living specimens; many with the sarcode apparently resolved into spores, which were shining, oU-libe globules, from one or two to half a dozen or more in number, and of pretty uniform size, being about 0.012 mm. Specimens mostly 0.066 mm. to 0.072 mm. long, 0.036 mm. to 0.042 mm. broad, and 6.018 mm. wide at the mouth. Ranging from 0.033 mm. to 0.09 iiim. in length, by 0.012 mm. to 0.042 mm. in breadth. Nucleus of the sarcode about 0.018 mm. Variety: several dead shells with the mouth oblique or subterminal; 0.06 mm. in length, 0.036 mm. in breadth, and 0.0135 mm. wide at the mouth. Variety: with a slight curvature approaching the mouth. A living specimen„0.06 mm. in length, 0.036 mm. in breadth, and 0.012 mm. wide at the mouth. 4. EtTGLTPHA ciLiATA. One living specimen observed. Shell ovoid, compressed, with three spines to one side, two to the other, and one to the fundus ; mouth with four thickened teeth. Length 0.06 mm.; greater breadth 0.024mm.; at mouth 0.009 mm. Resembled fig. 14, pi. xxxvi. 5. Tkinema enchblts. Mostly dead shells, small, and frequent. The cancellated structure not visible in the smaller but distinct in the larger ones. From 0.03 mm. to 0.078 mm. in length, 0.012 mm. to 0.042 mm. in breadth. Several with the sarcode encysted, and several with the latter resolved into spores. A pair of empty shells, observed adhering mouth to mouth, as in conjugation, and dis- posed in the same direction, and not in opposite directions as previously noticed. One of the shells 0.042 mm. long, the other 0.03 mm. long. 6. ACTiNOPHEYS SOL. Occasional ; in active condition. A pair observed either in conjugation or act of division. 7. Amceba eadiosa. Few. 8. A. VEEEUCOSA. Young condition as A . quadrilineata. 9. A. PEOTEXJS? Young. Occasional. 294 FEESH-WATER EHIZOPODS OF NORTH AMERICA. CONCLUDING REMARKS. In closing my observations on the Fresh-water Rhizopods, the results of which are now presented to the world, I am impelled to say that they are neither so complete nor so accurate as it was my desire they should be. At one time I was disposed to lay both manuscript and drawings aside, and once more go over the ground before making my researches public. It was only after several years of experience that I felt qualified to investi- gate the subject in the manner it merits and as I should wish to introduce it to the reader. But, taking into consideration the uncertainty of events, and the probability that I might not be able to obtain and investigate the same or similar materials under equally favorable circumstances, or have an equally favorable opportunity for publication, I concluded to send forth the results of my labors, imperfect as they may be. The novel things of the work must compensate for any deficiencies, and the experiences related will prove of assistance to students who may follow in the same path of investigation. I may perhaps continue in the same field of research and give to the reader further results, but cannot promise to do so ; for though the subject has proved to me an unceasing source of pleasure, I see before me so many wonderful things in other fields that a strong impulse disposes me to leap the hedges to examine them. The objects of my work have appeared to me so beautiful, as represented in the accompanying illustrations, and so interesting, as indi- cated in their history, which forms the accompanying text, that I am led to hope the work may prove to be an incentive, especially to my young countrymen, to enter into similar pursuits. The study of natural history in the leisure of my life, since I was fourteen years of age, has been to me a constant source of happiness, and my experience of it is such that, inde- pendently of its higher merits, I warmly recommend it as a pastime, than which, I believe, no other can excel it. At the same time, in observing the modes of life of those around me, it has been a matter of unceasing regret that so few, so very few, people give attention to intellectual pursuits of any kind. In the incessant and necessary struggle for bread, we repeatedly hear the expression that " ma,n shall not live by bread alone," and yet it CONCLUDING EEMAEKS. 295 remains unappreciated by the mass of even so-called enlightened humanity. In common with all other animals, the engrossing care of man is food for the stomach, while intellectual food too often remains unknown, is disre- garded or rejected. "Going fishing ?" How often the question has been asked by acquaint- ances as they have met me, with rod and basket, on an excursion after materials for microscopic study. Yes ! has been the invariable answer, for it saved much detention and explanation, and now, behold, I offer them the results of that fishing. No fish for the stomach, but, as the old French microscopist Joblet observed, "some of the most remarkable fishes that have ever been seen" ; and food fishes for the intellect. To my pupils, both of the University of Pennsylvania and Swarth- more College, but especially the boys and girls of the latter, who have attended my lectures on natural history, the work will be of interest, as they will recognize in its illustrations many of the simplest forms of animal life with which they have been made familiar through my instruction. Indeed, in the course of preparation of the book I have always had my pupils in mind, and I shall be glad if it serve as an additional aid to their studies. In conclusion, I embrace the opportunity of thanking those of my friends who have not only expressed a warm interest in my investigations, but who have aided me in my excursions, or who have collected materials in distant localities and sent them to me. Among them, especially, I take the liberty of mentioning Dr. Robert S. Kenderdine, Rev. Thomas C. Porter of Easton, Dr. Joseph K. Corson, U. S. A., Joseph Willcox, Dr. Isaac Lea, Clarence S. Bement, and Charles E. Smith. CHIEF WORKS AND COMMUNICATIONS EELATING TO THE FRESH- WATER RHIZOPODS, WITH LISTS OF THE FORMS DESCRIBED, AND A PARTIAL AND PROBABLE REFERENCE \0F THESE TO CORRESPONDING FORMS DESCRIBED IN THE BODY OF THE PRESENT WORK. Archer, ^I'^illiam. Numerous Memoirs and Communicatioiis on Fresh-water Ehizopods, published in the Quarterly Journal of Microscopical Science, from vol. vi, 1866, to vol. xviii, 1878, inclusive. The titles of the principal ones are given below, followed by a list of the forms described in aU. On Some Fresh- water Ehizopoda, New or Little Known, 1869, ix, 250, 386, pi. xvi, xvii, XX ; 1870, x, 17, 101; 1871, xi, 108, pi. vi, vii. On Ohlamydomyxa labyrinthuloides, a New Fresh-water Sarcodic Organism, 1875, XV, 107, pi. vi, vii E6sum6 of Eecent Contributions to Our Knowledge of "Fresh-water Ehizopoda," 1876, xvi, 283, 347, pi. xxi, xxii; 1877, xvii, 67, 107, 197, 330, pi. viii, xiii, xxi. ACANTHOCYSTIS, X, 26. A. Pertyana, ix, 199, 252; x, 32, pi. xvi, fig. 1; xii, 195. =A. cbmtophora? A. spinifera, xi, 137, pi. vi, figs. 7, 8; xvi, 364, pi. xxii, fig. 8. A. turfacea, xii, 195; xvi, 361. = Acanthocystis ch.etophoka. A. aeuleata, xvi, 365, pi. xxii, fig. 6. A. flava, xvi, 366, pi. xxU, fig. 7. AOTINOPHBYS, viii, 69 ; ix, 42. A. SOL, xvi, 297, 306. A. digitata, xv, 102. ACTINOSPH^RIUM EICHHORNII, XVi, 301. Amceba — aotinospliSBrium-like, xi, 101; xii, 94. A. villosa, Witt Unear appendages, vi, 19, 267 ; x, 305 ; xiii, 212 ; xvi, 337. = Ouramceba VOKAX. Amphitrema, vii, 174; x, 122. J. WrighUanum, x, 20, 122, pi. xx, fig. 4, 5. Amphiamella vestita, xi, 135, pi. vi, fig. l-€; xii, 87, 195. = Cochuopodium vestitum. A. violacea, xi, 126, 134 ; xvii, 464. A. digitata, xi, 129, 134. A. flava, xi, 130, 134. Arachnula impaUens, xvii, 347, pi. xxi, fig. 21. Arcella globosa, viii, 69. A. vtrLGAKis, xvii, 79. Astroeoccus rufus, xvi, 351, pi. xxi, fig. 2. Astrodisoulus, xiii, 320; xvi, 348. =Pompholyxophi!YS ? A. minutus, x, 114. =Pomphoi,yxophrys? A. ruler, x, 115. = Pompholyxophrys ? A. flaveacens, x, 115. = Pompholyxophkys ? 297 298 FEESH-WATEE EHIZOPODS OP NORTH AMEEIOA. Archer, William. A. flavocapeulatus, x, 115. = Pompholyxophrys ? A. radians, x, 115. = Pompholyxophrys? Ciliophrya infusionum, xvi, 300, pi. xxi, fig. 1. Chlamidophriis stercorea, xvii, 198, pi. xiii, fig. 3. = Pamphagtjs htaiinus t CKUimydomyaa, xv, 107, pi. vi, viii. Chondropus viridis, xvi, 358, pi. xxli, fig. 20. CLATHEUI.1NA ELBGAUS, viii, 71, 189; X, 117, pi. xvii, fig. 5 J xi, 322; xvii, 68, pi. xx, figs 23-25. CochUopodium pellueidum, xvii, 334, pi. xxi, fig. 8. ^Cochliopodium biumbosum. C. pilosum, xvii, 334. = Cochliopodium vbstitum. Cyphoderia truncaia, xvii, 203, pi. xiii, fig. 6. Cystophry8, s., no. =Pamphagus? C. HcBckcliana, viii, 295, 296 ; ix, 259, pi. xvii, figs. 1, 2 ; x, 112. =Pamphagus hyaijnus? C. OBulea, ix, 259, 421, pi. xvii, fig. 3; x,112. = Diplopheys akcheri ? Dactylosphmium viireum, xvii, 344, figs. 17, 18. Diaphoropodon, ix, 321 ; x, 123. D. mobile, ix, 394, pi. xx, fig. 6; x, 123; xii, 87, 194. Difflugia acropodia, xvii, 114. =Difflugia globulosaT 7). carinata, vii, 178 ; x, 21, pi. xx, fig. 12 ; xii, 195. =Nebela caeinata. D. COKONA, vi, 267. X). triangulata, vii, 174; xii, 195. D. vinosa, xviii, 212. JDiplopkrysf xi, pi. vi, fig. 9, pi. vii, fig. 10. DUrema flawm, xvii, 103, 336, pi. xxi, fig. 9. Euglyplia ampullacea, xvii, 203, pi. xiii, fig. 7. IE, sacdformis, xvii, 196. E. sfpinosa, xii, 90; xvi, 237. ^Placooista splnosa. M. tincta, xvi, 108; xvii, 103,330; xviii, 105. =A8SUIjna seminulum. Gromia, xii, 310. G. granulata, xvi, 343. Cr. paludoaa, xvii, 201, pi. xii, fig. 5. G. sodalis, ix, 322, 390; x, 124, pi. xx, fig. 7-11. = Pamphagus hyauqtosT Gymnophrys cometa, xvii, 348, fig. 22. Sedriocystis, xvii, 67, pi. xx, fig. 21, 22. Heteropheys, X, 107; xvi, 351. ff. JbcM, ix, 267, 318, pi. xvi, fig. 3; x, 108; xii, 195; xiii, 214; xv, 331; xvii, 103. = Eaphidiophrys elegans. H. MYEIAPODA, ix, 267, 320 ; x, 110, pi. xvii, fig. 4. S. marina, xvi, 354, pi. xxii, fig. 13; xv, 202. jBT. spinifera, xvii, 67, pi. xx, fig. 21, 22. Hyalodiscus eubicundus, xvii, ,342, pi. xxi, fig. 16. HyalospTienia lata, xvii, 110, pi. viii, fig. 5. = Hyalosphenia ccneata. M. ligata, xvii, 464. = Hyalosphenia coneata. Lecythvum hyaU/nwm,, xvii, 197, pi. xiii, fig. 1, 2. = Pamphagus hyalinus. Leptophrys cinerea, xvii, 345, pi. xxi, fig. 19. L. elegans, xvii, 345, pi. xxi, fig. 20. Mastigamceba aspera, xvii, 350, pi. xxi, fig. 24. Miorogromia sociaUs, xvii, 115, pi. viii, fig. 8. M. mudeola, xvii, 121, 194, 465, pi. viii, fig. 9. Ouramosba. On the proposed genus, xv, 202. . Pamphagus mutabilis, xii, 194, 423. Pelomyxapalusiris, xvii, 337, pi. xx, fig. 10-15. Pinadophora fluviatilis, xvi, 367, pi. xxii, fig. 5. Pinacocystis rubicunda, xvi, 367, pi. xxii, fig. 10. Plagiophrya Mertwigiana, xvii, 124. = Pamphagus. P. sacoiformis, xvii, 122, pi. viii, fig. 11. = Pamphagus. BIBLIOGRAPHY OF FRESH- WATER RHIZOPODS. 299 Archer, l¥illiaiii. p. seutiformis, xvii, 123, pi. viii, flg. 10. =Pamphagus mxjtabilis. P. aplKBiioa, xi, 146, pi. vii, fig. 11-16. := Pamphagtjs. Plahopus ruler, xvii, 349, pi. xxi, fig. 33. = Htalodiscus eubicundus. Platoum pamtm, xvii, 199, pi. xiii, fig. 1, 2. Pleurophrys f ampMtremoides, x, 17, 121, pi. xx, fig. 2. = PsEUDODirrLUGlA. P. ? compreasa, xvii, 204, pi. xiii, flg. 9. = Pseudodifflugia. P. f fulva, X, 17, 122, pi. xx, flg. 3 ; xiii, 437. = Pseudodifflugia. P. lageniformU, xvii, 204, pi. xiii, flg. 8. = Pseudodifflugia. P. aplumea, x, 17, 121, pi. xx, flg. 1 ; xvi, 343. = Pseudodifflugia gracilis. Podoaphcera Mwckeliana, viii, 67. = Clathrulina elegans. ■• POMPHOLTXOPHEYS, X, 105. p. PUNICEA, Syn. Hyalolampe fenestrata, ix, 386; x, 105, pi. xvi, fig. 4,5; xvi, 375. Pseudochlamys patella, Syn. Amphizonella flava, xvii, 107, pi. viii, fig. 1-3. = Young of ArCELLA VULGARIS. Pyxidiaula opercvlata, Ehr., Syn. Arcella patens. Clap, et Lachm. xvii, 110. = Young of ARCELLA VULGARIS ?- QUADRULA SYMMETRICA, XVii, 112, pi. viii, fig. 6. Q. irregularis, xvi, 337 ; xvii, 103. Eaphidiophbys, X, 103; xvi, 368. E. ELEGANS, xvi, 374, pi. xxii, flg. 19; xvii, 103. B. pallida, xvi, 370. jB. viridis, vii, 179; ix, 255; x, 103, pi. xvi, fig. 2; xii, 195; xv, 331. Ehizopod, ix, 323 ; x, 303 ; xi, 94, 101 ; xiii, 102, 317 ; xvi, 105, 109, 340, 343. SpTirerastrum conglohatum, xvi, 3.56. = Eaphidiophrys elegans. Troglodytes zoster, xvi, 331, pi. xxi, figs. 1-7. :=PAMrHAGUs hyalinus. Vampyrella SpirogyroB, xvii, 347. =Vampyrellalateritia. Anerbach, lieopold. Ueber die Einzelligkeit der Amceben. Zeitschrift fiir wissenschaftliche Zoologie, 1856, vii, 365, Taf. xix-xxii. Ammba UUnibosa, 374, Taf. six. = Cochliopodium bilimbosum. Amoeba aotmophora, 392, Taf. x. Amceba radiosa, Ehr., 400, Taf. xxi. Ammba princeps, 407, Taf. xxii. =Am. gromlamdica, Mb. 1872, 298; Nordp. 466, Taf. iii. Fig. 22. Z>. Martmanni, Abh. 1871, 143, 253, Taf. ii, Fig. 34. D. hermHana, Abh. 1871, 143, 253, Taf. ii. Fig. 10. i). feispamea, Abh. 1871, 272, Taf. iii, i, Fig. 23. =Nebela? D. hyaUna, Abh. 1871, 253, Taf. iii, Fig. 3. = Htalosphenia. D. jurassica, Abh. 1871, 274. =Difflugia spiralis. Z>. Icevigata, Abh. 1841, 413, 439, Taf. ii, i, Fig. 43. =Euglypha. I). Iwvis, Abh. 1871, 253, Taf. iii. Fig. 5. = PIyalosphenia. B.Lagena, Abh. 1841, 413, 445, Taf. iv, ii, Fig. 11; 1871, 143, Taf. ii, Fig. 2. = Cypho- deria AMPULLA. D. laxa, Abh. 1871, 254, Taf. iii. Fig. 22. =N'ebela collaris. D. lenta, Abh. 1871, 264. ^ Sphenoderia lenta. D. L^tolej)i8, Abh. 1871, 254, Taf. ui. Fig. 15. = Qtjadkula symmetrica. Z>. Uneata, Abh. 1871, 254. = Quadrula ? D. Liostoma, Abh. 1871, 254 ; Mg. Taf. xxxviii, xxi. Fig. 3. = Hyalosphenia t D. longicollw, Abh. 1871, 143, 254, Taf. ii. Fig. 30. D. Maerolepis, Abh. 1871, 254, Taf. iii, Fig. 12. = Quadkula. X>. margaritacea, Abh. 1S71, 264. = Cyphoderia ampulla. D. marina, Bailey, Abh. 1871, 264. =Quadrula?, marine. J), menibranacea, Abh. 1871, 274, Taf. iii. Fig. 1. ^Nebela? X>. Microstoma, Mb. 1872, 298; Nordp. 466, Taf. iii. Fig. 21. = Assulinaseminulum? D. missourienm, Abh. 1871, 143, 255, Taf. ii. Fig. 20. D. moliiooengia, Abh. 1869, 48, Taf ii, iii. Fig. 12. =Euglypha? D. ohlonga, Abh. 1831, 90; Inf. 131, Taf. ix. Fig. ii. D. Oligodon, Mb. 1844, 267 ; 1856, 337, Tafel, Fig. 10 ; Mg. Taf. xxxviii, A, xxi. Fig. 1. D. paoifica, Abh. 1871, 255, Taf. iii. Fig. 7. D. paradoxa, Abh. 1871, 255. D. Phiala, Abh. 1871, 143, 255, Taf. ii, Fig. 9. D. Pila, Abh. 1871, 143, 255, Taf. ii, Fig. 6, 7. =AssuLrNA seminulum? D. pilosa, Abh. 1871, 143, 256, Taf. ii. Fig. 28 ; Mg. Taf. xxxiv, v, B, Fig. 6. =Euglypha ALVEOLATA ? D. Planorbis, Abh. 1871, 264; Inf. 132. =Difflugia spiralis. D. prorolepta, Abh. 1871, 256; Mg. Taf. xxxiv, vii', I'^ig. 3. D. proteifmnis, Abh. 1830, 40, 62; 1831, 90; Inf. 131, Taf. ix. Fig. 1. =Difflugla GLOBULOSA. D. pwrpurescens, Abh. 1871, 143, 256, Taf. ii. Fig. 24. D. rectangularis, Abh. 1871, 256, Taf. ui, Fig. 16; Nordp. 466, Taf. iii, Fig. 20. =Eu- GLYPHA. D. relieulaU, Mb. 1848,218; Abh. 1871, 143, Taf. ii, Fig. 26. =Nebela collaris? B Boberti Miiller, Abh. 1871, 143, 256, Taf. ii, Fig. 16. = Euglypha. D. BoraimcB, Abh. 1871, 143, 257, Taf. ii, Fig. 25. D. Sch.wartzii,_Ah'h. 1871, 143, 257, Taf. ii. Fig. 15. 7). Seelandiea, Abh. 1869, 48, Taf. ii, ii, Fig. 23. = Cyphoderia ampulla. ^ D. Semirmlum, Mb. 1848, 379; Mg. Taf. xxxv, B, ii. A, Fig. 1. ^iAssulinaseminulum. D. Semen, Abh. 1871, 257 = 1). Seminulum, 264. =Assulina semlnui.um. 308 PEESH-WATEE EHIZOPODS OP NOETH AMEEIOA. Ehrenberg, Christian Crottfried. D. seriata, Abh. 1871, 257, Taf. iii, Fig. 30. =Euglypha. D. seUgera, Abh. 1871, 143, 257, Taf. ii. Fig. 30. =Euglypha alveolata. D. Shannoniana, Mb. 1872, 29S; Nordp. 4G6, Taf. iii, Fig. 18. D. aguamata, Mb. 1848, 218; Abh. 1871, Taf. U, Fig. 29 ; Mg. Taf. xiv, Fig. 98. = Nebela COLLAKIS. D. spikalis, Mb. 1840, 199 ; Abh. 1871, 274, Taf. iii. Fig. 25-27. D. apirigera, Mb. 1853, 526; Abh. 1871, 274, Taf. iii. Fig. 4. =Hyai.ospheniaemgans? D. atriala, = D. atriolata, Abh. 1871, 264. = EuGI.ypha. D. strigosa, Abh. 1871, 143, 257, Taf. ii, Fig. 31. =Euglypha steigosa. D. airiolata, Abh. 1841, 413, 439, Taf. ii, i, Fig. 44; Mg. Taf. xiv. Fig. 97; Taf. xxxiu, iv, Fig. 3 ; Taf. xxxiv, v. A, Fig. 8. = Euglypha. D. auiacuta, Mb. 1872, 298; Nordp. 466, Taf. iii, Fig. 19. = Euglypha? D. ieaaellata, Abh. 1871, 143, 258, Taf. ii. Fig. 32. =Qtjai>kui.a symmetkica. D. undnata, Abh. 1871, 258, Taf. iii, Fig. 13. = Cyphoderia ampulla. Pyxidimla opereulata, Inf. 165, Taf. x. Fig. i. =Arcella? Tiichodiacua sol, Inf. 305, Taf. xxxi, Fig. ix. = Vampyeella latekitla ? Focke, GustaT Woldemar. Ueber schalenlose Eadiolarien des silssen Wassers. Zeitschrift fiir wissenschaft- liche Zoologie, Leipzig, 1868, xviii, 345, Taf. xxv. Sadiolarien, No. I, 353, Fig. 1 a-ft. ^ Eaphidiopheys elegans? " No. II, 354, Fig. 2 o-(i!. = Vampyeella lateritia ? " No. Ill, 355, Fig. 3 a-e. =Acanthocystis. Fresenius, O. Beitrage zur Kenntniss mikrospisclier Organismen. Abhandlungen der Sencken- bergischen Naturforsclienden Gesellschaft. Prankfurt am Main, 1856-8, ii, 211, Taf. x-xii. Amosba lateritia, 218, Taf. x, Fig. 13-19. = Vampyeella lateritia. Arcella hyalina, Ehr., 219, Taf. xii,. Fig. 1-24. ^Pamphagus hyalikus. ■Trimema adnua, Duj., 223, Fig. 25-27. ^Tetnema enchelys. DiFPLUGiA SPIEALIS, Ehi., 224, Fig. 37-42. D. oUonga, Ehr., 225, Fig. 43-45. = Difplugia lobostoma. Cyphoderia margariiaeea, Schlum., 225, Fig. 28-36. = Cyphoderia ampulla. Fromentel, E. de. Etudes sur les Microzoaires ou Infusoires proprement dits. Paris, 1874. Amoe- biens, 345. Tnchammha radiata, 345, pi. xxviii, fig. 1. =Heteeophey8? T. Mrta, 345, fig. 4. =Amceba villosa. Thecamosba quadripartita, 346, fig. 3. =AMa5BA quadeilineata, or young of Amceba VEREUCOSA. Amoeba craaaa, Duj., 346, pi. xxix, fig. 1. A. ramoaa, Duj., 346, pi. xxviii, fig. 2. =A. proteus. A. guttula, Duj., 347, pi. xxix, figs. 2,3,5. =Young of A. puoteus? A. iracMata, Duj., 347, fig. 4. =Am. compresm, var. of Difflugia ptriformis. D. CORONA. Z). lajeniformis. = Difflugia ueceolata. D. proteiformia. = Difflugia lobostoma. D. PYBIFORMIS. On Actinophrys sol, 23. Note on the Enemies of Difflugia, 75. Notice of some New Fresh- water Ehizopods, 77. OUEAMOSBA VOEAX, 78. 0. Xapaa, 78. = Ouramceba vokax. Difflugia lobostoma, 79. D. crenulata. = Difflugia lobostoma. D. pyriformis. D. SPIRALIS. D. corona. D. acuminata. D. ENTOCHLORIS. = DiFFLUGIA PYRIFORMIS. D. amphora. = Difflugia urceolata. D. ligata. =:Hyalosphenia ccneata. Catharia. = Hyalosphenia. Notice of some Fresh- water and Terrestrial Ehizopods, 86. Amoeba sabulosa, 87. = Pblomyxa villosa. Amasha zonaUs, 87. = Cochliopodium pellucidum. Gromia terricola, 88. Notice of a Eemarkable Amoeba, 142. Deinamceba mirabilis, 143. On the mode in which Amceba swallows its Food, 143. Amoeba prvnceps. = Amceba proteus. Clathbulina elegans, 145. Notice of some Ehizopods, 165. Deinamceba mibabilis. # f BIBLIOGRAPHY OF FRESHWATER RHIZOPODS. 313 Leidy, Joseph. Difflngia vas, 155. = Var. of. Difflugia pyriformis. jD. olla, 156. = Var. of Difflugia ukceolata. Catharia. = Hyalosphenia. Difftugki ( Catharia) papilio. := Hyalosphenia papilio. J). (C.) elegana. = Hyalosphenia elegans. Nebela. D. (N.) ansata. ==Nebela ansata. D. {N.) equi-calceus. = Nebela hippoceepis. D. {N.) ephagni, 157. = Heleopeea picta. X). (_N.) numaia. = Nebela collaris. , - D. (JV.) harbata. = Nebela bakbata. D. (^. ) flalelluhim. = Nebela flabellulum. Notices of Rhizopods, 166. Clatheulina elegans. actinosphieridm bichhornii. * AcanthocysUs viridis. = Acanthocystis ch^tophora. Eaphidiophrys elegans, 167. Amceba quadriUneata. = Young of Amoeba veeeucosa. Artueba viridis. Am(eba tentaealaia. = Dinamceba mieabilis. On Supposed Spermaries in Amceba, 168. I^otices of Rhizopods, 225. Eugltpha alveolata, 225. E.compre88a,^l3&. = Euglypha ciliata. E. spinosa. = Placocista spinosa. E. CRISTATA. jB. globosa. = Sphbnoderia lenta. E. Irunnea. =Assulina semintjlum. Tnnema amrns, 227. = Teinema enchelys. Cyphoderia margaritaeea. =: Cyphodeeia ampulla. CalUca=: Lagynis ialtiea (Sohnltze). Difflugia glohularis, figs. 1, 3, 17, 21. =Dipi'i.ugia globulosa. D. ma/rswpifortKis, figs. 3-5. = Difflugia consteicta. D. cassis, fig. 6. = Difflugia constricta. D. mitrifomiis, figs. 7, 8. = Difflugia acuminata ? D. PTEiFOKMis, figs. 9, 10 ; also fig. 12, specimen of the mitriform series. D. acuminata, fig. 11 ; also figs. 12, 12o, 126, specimens of the acuminate seiiea. Oblong variety, figs. 13, 14. = D. globulosa. Difflugia lagmiformis, figs. 15, 16. Difflugia urceolata. D. tuherculata, fig. 18. = D. globulosa ? D. corona, figs. 19, 20. X). aculeata, plain variety, fig. 22. =Centeopyxis ecoknis. X). aouleata, fig. 23. = Centropyxis aculeata. D. spiralis, figs. 24, 25. D. symmetrica, fig. 26. = Quadkula symmetrica. . Transition forms, figs. 27-33. = Nebbla collaris. Difflugia Arcella, figs. 34-38. = Aecella vulgaris. Two Difllugias in conjugation, fig. 39. =D. pyriformis and D. globulosa. Difflugia, fig. 40. ^ Difflugia pyriformis. Varieties of Euglyplta, flgs. 41-45. =Euglypha alveolata ? Euglypha enckelys, figs. 46, 47. = Trinema bnchblys. U. margaritacea, fig. 48. = Cyphodekia ampulla. On the Structure and AflSnities of the Polycystina. Quarterly Journal of Micro- scopical Science, 1865, v. Transactions of the Microscopical Society of Lon- don, 1865, xiii, 75. A classification of the Ehizopoda, 64. The Amoeban, Actinoiihryan, and Difflugian Ehizopods. Monthly Microscopical Journal, 1875, xiii, 210. IVestoii, J. On the Actinophrys Sol. Quarterly Journal of Microscopical Science, London, 1856, iv, 116, pi. ix, flgs. 3-7. Wright, E. Percival. Quarterly Journal of Microscopical Science, x, 1870, 305. Cystophrys Sasckeliana. = Pamphagus hyalinus ? Upright, T. S. On the Reproductive Elements of the Ehizopoda. The Annals and Magazine of ]S'atural History, London, 1861, vii. 360. IVyman, J. On Amoeba. Proceedings of the Boston Society of lifatural History, 1862, ix, 281. IISTDEX. Names in small capitals refer to descriptions in the body of the work ; those in italics to synonyms and forms incidentally mentioned. Page. AcANTHOCYSTis 264, 268, 270, 291 Acanthocj/stis ^ 256,264 A. aculeata 271 A. CH.^TOPHO&A - ' 264 A.pallida 264 A. spinifera 256,257 A. turfaeea 264 A. viridis 264 ACTINOSPHiEKiCM: 258 A. EICHHOKNlt 259 ACTINOPHETS 234 A. brevidrrhis...^ 271 A. difformia 235 A. Mchhornii 235,259 A. oculata 235,250 A. Pertyana 271 A. PICTA 241 A. SOL 235,293 A. Sol 250,259 A. viridis ^ 264 Allodictya 145,150 Amiha 30 A. divergens . ..^ 31 A. Miilleri 31 A. princeps... 31 A. EoeMli ...» 31 Amceba 30 Amceia 62,184,253 A. actmophora 184 A. Wlimboaa ...184,185 A.Blatiae 300 A. Jn-achiatd 58 A. chaos 31 A. communis 31 A. difflueiis 32 A. Gleichenii 47 A. guUula 47 A. lateritia 253, 254 A. Umax 47 A. natans 53 A. princeps 31,62 A. PROTEUS 30,35,291,293 A. guadrilineata 53,293 A. radiosa 58,291,293 A. ramosa 31,58 A. sabulosa 73 21 BHIZ Page. A. tmiacuXata 81,90 A. VILLOSA 62,63 A. mlloaa 67 A. VERRUCOSA 53, 293 A. with processes 67 A. zonalis 184 Amphizonella 184 A. vestita 188 A.VIOLACEA 291 Ampwllaria 201,202 Arachnula impatiens 283 Arcella 166,292 Arcella 95,180,190 A. aculeata^ 180 A. angulosa 170 A. Arctiscon 120 A. ARTOCREA 178,179 A. borealis 121 A. caudicwola 226 A. constricta , 120,226 A. costata 176 A. dentaia 170 A. DENTATA ; 177 A. Diadema 180 A. DiscoiDES 173,290 A. Disphcera 226 A. ecornis 180,181 A. Enchelys 227 A. globosa 176 A. giiatimalensis 120 A. hemispheriea 170 A. hyalina 194,195,226 A. laticeps _. 121 A. lunata 120 A. Megastoma 227 A. MITRATA 175,290 A. Nidus Pendulvs 226 A. OfcCTii '. 177 A.peristicta 173 A. Pyrum 227 A. reticulata 227 A. rostrata 227 A. senata 227 A. siellaris 177 A. stellata 177 A. viridis .... 170 3Sil 322 IKDEX. Page. A. VULGAMS 170,171,290,291,292 ArcelUna vulgaris 170 ASSULINA 224 Assulina 144,201,206 A. admtca - . 202 A. aldbamensis 202 A. iilveolata ^ -, 208 A. amphora 208 A. ampulla - 202 A. areolata 208 A. assulata 142,144 A, carolinensis 142 A. Floridae 208 A. lenta 229 A. Leptolepis 142 A. margarilacea 202 A. molluccennis 2C8 A. Eoherti Muller 208 A. Seelandica 202 A. SEMEsruLUM : 225,290 A. tuierculaia. 208 A. uncinata 202 BlOMTXA 281 B. VAGANS ■- 281 Campascus 204 c. coknutus 205 Catharia , 128 C. elegans 140 a ligata 129 C.papilio 131 Centropyxis : 180 C. ACULEATA 180,181,290,291,293 C. Diadema 180 C. ecornis 180,181,290,291 Chaixengeuida 21 Chaos Frotlieus ■. 30 ClATHRULINA 272 C. ELEGANS 273,290 COCHLIQPODIUM 184 C. BILIMBOSUM 184,185 C. pellucidum 184,185 C. pilosum 188 C. VESTITUM. 188 Corticella aaiiminata 109 C. pyriformis 99,142 0. spiralis 124 Corijcia 190,191 Corycie 190,191 Cyphodeeia 201 C. AMPULLA 202,290,291 C. Dujardini .' 191 C. margaritacea 202,204 Cgstophrys 256 C. ooulea 256,257 Dactjjlospliwrium viireum 93 DiFFLUGLi 95 Difflugia 98, 99, 109, 124, 128, 145, 180, 190,201,206,224 D. acdntltophora 207 Page. acaulis - 109 acropodia 96 aeuleata 180 ACUMINATA 109,110,289,291 adunca --- 202 alatamensis 202 amphora 106,207 ampulla - 202 annulata 145,150 ansata 158 ABCULA , 116,117,289 areolata - - 207 assulata 142,144 haedllariarum 109, 112 iarbata 159 Mnodis ^ 145, 150 eancellata 145, 150 earinata 154 ., 142,144 Carpio 145,150 cassis 120,123 collaris - -.145,150 COMPRESSA 99, 148 CONSTRICTA 120, 121, 289, 291, 292, 293 CORNUTA 99 CORONA 117,118 CRATERA 108 crenulata 102 elegans : 140 Enchelys 194,226 entocliloris 99 equicalceus 156 flaliellulum 152 FloridcB 207 globularis 96 GLOBULOSA 96,289,291,292 Helix 124 Ixyalina (error ; should be Enehelys) 195 Icevigata 207 Lagena 145,202 lageniformis 106 laxa 145,150 lenta 229 Leptolepis 142,144 ligata 129 LOBOSTOMA 112,291 murgaritacea 202 marsupiformia 120,123 mitnformis 108,109,124 moluccensis 207 NODOSA 99 nnmata 145 oblonga 102 olla 106 papilio 131,133 Pilosa 207,214 peltigeracea 145^ ico proteiformis 96, 98, 99, 108, 109, 112, 117, 120, 124, 142 nroEx. 323 Page. p. proteiformis mon^trosa 124 D. PYRIF0RMI8 98, 99, 100, 289, 291 , 292 D. pyriformis 109 D. reotangularis , 207 Z). retieella 150 D. reticulata 145, 150 D. Boierti Muller 207 D. Seelandica 202 D. Semen 225 X). Seminvlum 225 JD. aeptifera , 124 D. seriata 207 D. setigera 207 D. Shannoniana ,. 208 D. SPiKAiis 124,289,299 D. spirigera 142 Z>. sphagni 162 D. striata 207 D.atrigosa 314,216 D. 8tr%olata 207 D. subacuta • 208 D. symmetrica 142,145,150 Z). tricuspis 112 2). tubereulata 115 D. uncinata 202 D. UECEOLATA 106 D. VAS 99 DlNAMOEBA 80 D. MIRABILIS 81 DiPLOPHKYS 256 DiPLOPHRYS ARCHEKI 256 Mchinopyxis 180 E. aculeata 180 D. hemispheriea 184 E. tentorium 184 Elaorhanis 256 M. cincta 256 Endamceba 300 E. Blatt^ 300 EUGLYPHA „ 206 Euglypha 201,221,224 E. ALVEOLATA 207,208,292,293 E. laltica , 202 E. BRACHIATA 220,290 E. brunnea 225 E. ciLiATA 214,215,290,293,293 E.compressa 214,216,218 E. CRI8TATA 218,219,290 E. curvata 203 E.Enclielys 227 E. globosa , 229,230 E. Imis 207 E. margaritacea 202 E. MTJCROKATA 219,220,290 E. pleurostoma 227 E. setigera 207 E. Seminulum 225 E. spinosa 221 E. sti-igosa 214,216,290 Page. E. tegulifera 221 E. tincta 225 E. tubereulata , 207 Exassula . 95 E. tricuspis 102 FlLOSA 23 FiLOSB Protoplasts 189 FORAMES'IFERA, 7,14,277 Fresh-water Ehizopods 2,8 Gromia 190 Gromia 277 G. hyalina 194,195 G. tereicola 277 Gymnophrys cometa 284 Helbopera 162 H. petricola 16.5,290 H. picta 162,290 SeUophi-ys variabilis (erroneously quoted as Heterophrys) 243,244 Heliozoa 7,233 Seterocosmia Arctiscoa 121 S. guaUmalends , 121 H. peristicta 173 H. Fyrum 227 H.stellata 177 Heterophrys 242 M. Fockii 243 H. myriapoda 243 M.varians 243 Hologlyplia 142,144,201,202 Homosoclilamys - 180,100" S. angulosa '. 170 H. constricta 120,227 M. deniata 177 H. discoides 173 n. DisphcBra 227 H. eoomis 180 S. Enehelys 227 S. hyalina 194,227 S. Iwnata 121 S. rostrata 227 Hyalodiscus 94 •h. rubic0ndus .■... 94 Hyalolampe 271 H. exigua.... 271 h. fenestrata 271,291 Hyalosphenia 128 h. cukeata 129 H. ELEGANS 140,290 ff.lata 129 H. ligata 129 H. PAPILIO 131,132,290 H. TINCTA 138 Lagynis 201 L. baltica £02 Leequereusia 95 L.jurassica 124,125,127 Lecythium 190 X. hyallnum 194 324 ETOEX. Page. LOBOSA 23 LoBOSE Protoplasts 23 Maatigamoeba aspera 93 MONEKA 7,19 Nebela 145 N. ANSATA 159,289 N. BAKBATA 159,160,289 N. Unodis 289 N. CARINATA 154,289 N. CACDATA 100,161,289 N. coLLARis 145,146,289 jV". equicalceus 156 N. FLABELI.ULTJM 152,289 N. HIPPOCEBMS 156 N. numata 145, 150 N. retorta 289 N. spliagni 162 Odontodiciya 145,150 OCRAM(EBA 66 O. BOTULICATJDA 71,72 0. lapsa 67 O. VORAX , 67 Pamphagus 190 P. AVIDUS 196 p. CUEVUS 196 p. HYALINU8 194,195 p. MCTABILIS 191,193 Pelobius 72 Pelomyxa 72 P. palnstris 74 P. VILLOSA 73,75 Peritricha Sol 235 Placocista 221 P. SPiNOSA 221,222,290 Plagiophrys 190 P. ct/lindrica 197 P. scuiiformis 191,192 Plaltopus ruber ■ 94,95 Pleurophrya 197 P. ampMtremoides 198,200 P. amphora 201 P. angulaia 198,201 P. compressa 198,201 P.fulva 198,200 P. lagenifoi'mia 198, 201 P. sphariea 198,200,201 Podosphoura 272 P. ffmckeliana 273 Pompkolyxophrys 271 P. fenestrata 271 Proteus 30 P. difflums 31 Protista 7 Protoplasm 4 Protoplasta 7,8,23 P. FiLOSA 189 P. LOBOSA 28 Protozoa 1 Page. Pseudochlamys patella 175 PSEUDOMFFLUGLA 197 p. GRACILIS 198,199,290,292 PSEUDOPODS 5 QUADRULA 142 Q. SYMMETRICA 142,143,290,292 Eadiolaria 7,13 Raphidiophrys 248 r. elegaks 250 B. pallida 250 R. viRiDis 248,249 Eeticella 145 B annulata 145 B. asterophora 150 B. Mnodis 145 B. caneellata • 145 E. Carpio 145 B. collaria 145 B. laxa 145 B. reticulata 145 Rhizopoda 1,4,7 Sarcode 4 Setigerella 206 S. aeanthophora 208 S. clUata 214 S. piloaa 214 S. setigera 208 S. gtrigosa 214 Sphceraatrum conglobaium 250 Sphbnoderia 229 S.LENTA 229,230,290,292 S. MACEOLEPIS 232,290 SPONGILLA AMffiBOIDS 62 Sticlwlepia 227 ^ a ' * ■* 14, t % PLATE JoF. Leidy. Dei ..2lH,r i-T^. LitK AMOEBA PROTEaS PLATE II. Figs. 1-13.— AMCEBA PEOTEUS. Fig. 1. Individual iu a condition repeatedly observed immediately Bucceeding those represented in figs. 1, 2, of tlie preceding plate. Body ovoid with long divergent pseudopods. n, nucleus ; p. v., con- tractile vesicle. 200 diameters. Ditch below Philadelphia. Fig. 2. Au individual of stellate' form, as frequently observed when swimming. The largo con- tractile vesicle central, with the nucleus in advance to the left. Same locality. Fig. 3. Small individual, similar to that of fig. 8 of the preceding plate and found with it. p. v., contractile vesicle; «, nucleus. A large diatom extends across the posterior part of the body. 500 diameters. Fig. 4. An active individual with a profusion of pseudopods, containing a large granular nucleus, together with vacuoles, brown food-balls, diatoms, minute crystals, etc. 250 diameters. In several similar individuals the nucleus ranged from 0.032 mm. to 0.036 mm. broad by 0.02 mm. thick, and the contractile vesicle enlarged to 0.036. With Bladder-wort, Jacksonville, Florida, February, 1875. Fig. 5. Individual from China Lake, Mount Gilbert, Uinta Mountains, Wyoming Territory, August, 1877. The yellow septate alga seen in the figure was afterwards observed to be expelled. 200 diameters. Fig. 6. Robust individual, containing two contractile vesicles and a discoid nucleus. Among the food contents of brown balls, grains of sawdust, etc., there may also be noticed an Arcella. 270 diam- eters. Absecom pond. New Jersey. Another individual accompanying the former, at one time extended in a cylinder, with a single divergent psendopod, and measured 1.2 mm. in length. Fig. 7. A large and unusually pale, translucent, and seemingly starved individual, containing only colorless food-balls, together with clear vacuoles and contractile vesicles. Ko nucleus detected. 200 diameters. Sphagnous bog-water, Pokono Mountain, Monroe County, Pennsylvania, August, 1876. Fig. 8. Small individual, found in company with that of fig. 3.- 2.'>0 diameters. Fig. 9. Appearance of the nucleus in a large individual like those of figs. 1, 2, from the same locality. 350 diameters. Fig. 10. Appearance of the nucleus of another and similar individual after the action of acetic acid. 250 diameters. Fig. 11. Extremity of a chief pseudopodal extension, intending to represent the mode of entrance of the granular endosaro into the advancing ectosarc. In the former many clear vacuoles and numerous crystals are seen. 500 diameters. Fig. 12. Apparent forms of crystals as seemingly observed in tile same individual from Which the preceding figure was drawn. 2,500 diameters. Fig. 13. Api>arent forms of other crystals observed. 1,00Q diameters. Figs. 14-16. Probably young of AMCEBA VILLOSA. £00 diameters. From water squeezed from wot moss from the crevices of pavements in Philadelphia. Fig. 14. Individual containing a discoid nucleus, and as food several diatoms and a fragment of Lyngbya. Figs. 15, 16. Two views of the same individual, ending in a posterior minutely villous ball. U^S. GEOLOGICAL SURVEY OF THE TERRITORIES. PLATE II, 1.^ ^ =5in Ittir^S n Li ,Io;^ l_,eia.y i'ei AMOEBA PROTEUS. PLATE"! II AMCEBA VERRUCOSA. Lvnabva many of the segments of which were changed to brown as a result oi "iS?™"":,/"" "t"'";^^;"- ^^ Fig™ Individual with much wrinkled ectosaro ending in a posterior mmntely papillose extremity. It exhihSed ttaee persistent longitudinal lines. The endosaro contains a discoid nucleus and two con- LrtOe vesiclS &a^^^^^ united before collapse and three afterwards appeared m the same position. FIG a ^ individual nearly like the former, but exhibiting no longitudinal lines. ■ FIG 3 aS indi^dual with tonv longitudinal lines, a small nucleus, and large contractile vesicle. F G 4 aS ndi^dual which when first observed looked nearly like the former, but which subse- quentlv d scharged the large pouch-like drop of' yellowish Uquid and ^^"^^"""l^fe^.f f^*^fX l/'^i; bya Many of the latter were at first green, and the surrounding hquid when within the body ot the .nimal a^so i^,Pf„«^^- S--^,f-,,,,ed from moss growing in the crevices of the brick pavemeirt of my house iii Philadelphia; found in association with the Wheel-animalcule, JJofe/e^ toJ^o™, June, 1874. ^ Fig 5. Individual comparatively quiescent, with nucleus and contractile vesicle. Fig 6 Individual with nucleus and food, but the contractile vesicle collapsed or absent. Fig' 7' Individual with nucleus, two contractile vesicles, and food-balls. , ^ ^1 Fig 8. Small individual. It moved quickly with the^broad etid forward. Several contractile vesicles would appear, conjoin in a single one and then collapse. Frequent form m the bog at the toot of the Zoological Garden, Philadelphia, June, 1878. ^^ , ., ., ^ ^. ^-i ■ i^o w-hi„i, mi Fig 9 SmaU individual with active movement. It exhibits five contractile vesicles which all conjoined'in one before collapse. 500 diameters. Frequent in bog-water, Broad Mountain, Schuylkill °"^ Fig?10.^ An individual widely spread and exceedingly sluggish in movement ; with a nucleus and contractile vesicle. 686 diameters. „ , „ , n ■ ■ Fig 11 The same individual, magnified half the extent of the former, as observed swimming. From the pavement at the fountain in Sont of the City HaU, on Market street, Philadelphia. Fig 12 Individual with three longitudinal lines. It contains a nucleus, two contractae vesicles, together with fragments of Lyngbya, and a diatom. 333 diameters. Fountain in Fairmount Park, Fig. 13. An individual with four longitudinal lines. It shows two contractile vesicles, of which the larger is in the act of collapse. With the preceding. 333 diameters. Fig. 14. An individual with five or six longitudinal lines. The contractile vesicle m the act of collapse. 500 diameters. With the preceding. . , , r .. Figs. 15, 16. Two views of an individual, with four longitudinal Unes. A variable number ot small contractile vesicles would appear as seen in fig. 15, conjoin as in fig. 16, then expand to a regular sphere and collapse. Fort Bridger, Wyoming Territory, August, 1877. Fig. 17. Individual with two longitudinal lines. The contractile vesicle nearly collapsed. Same locality. Fig. 18. Individual with four longitudinal lines. It contains a nucleus, many clear vacuoles (inadvertently colored by the lithographer), and at the posterior extremity a large contractile vesicle. Common in Swarthmore brick-pond. Figs. 19-27. Xoung forms, observed among green algous material, Lyngbya, etc., scraped from the brick pavements in damp shaded places in Philadelphia, and preserved a few days in a dish with water. SmaU actively moving individuals, exhibiting mostly two to four longitudinal, lines or folds, containing a nucleus and a large posterior contractile vesicle. 500 diameters. Fig. 28. Mature form, found with the preceding. 500 diameters. Fig. 29. Mature form. Found in association with those of figs. 5-7. 333 diameters; Fig. 30, Individual containing a nucleus, contractile vesicles, and food consisting of yellowish and colorless granular balls, a diatom, and grains of sand. 500 diameters. Marsh of the Uinta Mount- ains, Wyoming Territory, August, 1877. Fig. 31. Individual, with nucleus, and large contractile vesicle (to left of the middle). The food- contents consist of abundance of the alga Lyngbya. The large posterior vacuole, with the greenish liquid and numerous isolated segments of Lyngbya, was observed to be expelled. 500 diameters. Among the algous slimeatthebaseofthe fountain. Eleventh streetnearChestnutstreet, Philadelphia, September, 1876. Fig. 32. Individual, from among Osoillaria and other algae preserved during the winter, observed with others of same character, February, 1875. Fig. 33. Individual of sluggish habit, with discoid nucleus, contractile vesicle, and food-balls. 200 diameters. Swarthmore brick-pond. Fig. 34. Individual of exceedingly sluggish habit. With large discoid nucleus, contractile vesicle, and food-balls. 500 diameters. Sphaguous swamp of Vineland, New Jersey, September, 1876. The contractile vesicle from its first appearance to its greatest expansion required about ten minutes ; its collapse, about six seconds. ^ Fig. 35. An almost motionless individual, without conspicuous contents except the contractile vesicle, which was observed to collapse and reappear. 500 diameters. Fort Bridger, Wyoming Terri- tory, August, 1877. Fig. 36. Individual, with oval nucleus, contractile vesicle (to the right), and food-balls (errone- ously colored). 200 diameter?. From ooze on the rocks below Fairmount, Philadelphia, October, 1875. FiG. 37. Small active individual, found with the preceding. Fig. 38. Large sluggish individual, found with that of fig. 34. Besides the oval nucleus, and large contractile vesicle, it contained a Difflugia constriota and a Tiinema enchelys. 500 -J-; us. GEOLOGICAL SURVEY OF' THE TERRITORIES. PLATE in. '4 ** ' \ / y' C 6 ff ^;y 0',-] y e^ ■>rit- #:;-^.: // ':^ Tnoi Sinclair-& Scr, AIVTOEBA VERRUCOSA PLATE IV. Figs. 1-18.— AMCEBA EADIOSA. Figs. 1-4. Four views of the same individual, exhibiting the successive changes of shape within a few minutes. From a pool at Fort Bridger, Wyoming, August, 1877. The pink globule withiu repre- sents the contractile vesicle. Of the other globules two were food-balls and the remaining one probably the nucleus, though it was not very distiuct. 500 diameters. Fig. 5. Individual with globular body and long nearly linear rays, as seen floating. It contained a large clear globule and a smaller one. The contractile vesicle absent or collapsed^ The animal sub- sequently assumed a more stellate appearance. Fig. 6. Another individual accompanying the former. At first stellate it then assumed the tripod form, with central contractile vesicle as represented. In neither this nor the former specimen was a nucleus detected. From a spring on Darby Creek, April, 1875. Fig. 7. Individual of globular form and long linear rays, with contractile vesicle, but no nucleus. From the gutter at the fountain on Market street, in front of the City Hall, Philadelphia, August, 1876. It subsequently assumed a more stellate appearance, with shorter, thicker, and more conical rays. Fig. H. Individual with globular body and comparatively short conical p-eudoijodal rays. It con- tains two contractile vesicles, which afterwards united in one. It also contains a diatom and a large ■ globule, with apparently a central, darkly-defined corpuscle. The creature subsequently became more stellate and with longer arms. From a springy place on Darby Creek, Delaware County, Pennsylvania, May, 1875. Figs. 9-11. Three views of the same individual, from China Lake, Uinta Mountains, Wyoming, August, 1877. Fi^s. 9, 10, as seen floating. Fig. 11, as seen creeping, with numerous long digitate pseudopods diverging in advance. The nucleus is seen in feont with a clear surrounding zone; the contractile vesicle central. Fig. 12. An individual, resembling the former, as observed floating. From a ditch, among Duck- meat, below Philadelphia, September, 1874. Fig. 13. An individual which, when first noticed, had a more stellate appearance, as in figure 4, but afterwards applying itself to the surface of the object-glass it retracted its pseudopods and slowly spread out so as to appear as in the present figure. At first it contained but few conspicuous globides, but a multitude were subsequently developed, and one among them becoming much enlarged finally collapsed. From the same locality as that of figure 8. Figs. 14-16. Three views of the same individual, exhibiting the successive changes of shape within a few minutes. From a dish of water with algse and other -aquatic plants, preserved during the winter. March, 1874. 333 diameters. Figs. 17, 18. Two individuals from mud collected at the mouth of Cooper's Creek, near Camden, New Jersey, May, 1874. 500 diameters. These in creeping on the object-glass extended a pair of broad, thin lateral expansions, from which radiated narrow pointed pseudopods. From time to time one or more of the latter would slowly vibrate from side to side. One of the specimens (fig. 18) dragged after it a laKe particle of quartz sand. Figs 19-21. SPONGILLA AMCEBOIDS. Obtained from the yellowish fresh-water sponge {Spon- gillafragilis) attached to the under surface of rocks below Fairmount dam, in the Schuylkill River, Philadelphia. 500 diameters. Figs. 19, 20 are nndistinguishable from Amoeba radiosa; fig. 21 resembles A. verracosa. Each contained a nucleus and from one to threp contractile vesicles, together with color- less or yellowish granular balls, which in true Amoebas would be viewed as food-balls. Figs. 22-24. An Amoeba of uncertain reference, but probably a variety of Amoeba protens. Fig. 22. An individual, as seen creeping from left to right, projecting in advance broad, clear lobu- lar pseudopods. From the sides and at the posterior extremity there projected a variable number of incessantly changing pointed conical pseudopods. The interior exhibits, from behind forward, a large contractile vesicle, a multitude of minute desmids, a nucleus, and a number of clear globules. 250 diameters. From the soft ooze in the Lehi^ River, near Fasten, Pennsylvania, June, 1874. Fig. 23. An Amoeba, with many conical pseudopods, mostly acute and divergent from the part of the body in advance, the posterior extremity ending in mammillary processes. 500 diameters. Fig. 24. Another and larger individual of the same kind as the preceding, with many poiated conical pseudopods ; the posterior extremity of the body ending in mammillary processes. The interior contaming a multitude of pinkish globules, incessantly changing in number and size, together with a long doubled filament of Oscillaria and other algas. From the posterior end of the body, as seen in the figm-e, a discharge of effete matters occurred. The individuals of figs. 23 and 24, together with many similar ones of various sizes and inter- mediate forms, occurred m water from Absecom pond. New Jersey, collected in the autumn of 1875 and preserved during the winter until March, 1876. o=n J- ^'^' ^^' ^^^^^ PROTEUS. An individual from Absecom pond. New Jersey, November, 1874. Z50 diameters. Besides the usual granular protoplasm, the contents consisted of brownish-vellow and green food-balls, many crystals, sevpral largo clear globules, a uniformly granular nucleus ('seen to" the nght of the centre), and a large contractile vesicle (seen to the left). Ai-ouud the latter may be ob- served haU a dozen darkly granular balls, the contente of which exhibited lively swarming movement. ■^■u ^1 ^^--^^ amoeboid animal, probably of the same character as those of figs. 23 and 24, and found with them. It moved slowly and contained a multitude of scattered chlorophyl grains of nearly uni- *°f™ ^}^^- These were first supposed to be a constituent element of the structure, as in some of the Difflugms and m Hyalospkema papilio. 500 diameters. A similar specimen was observed occupying a space of 0.18 by 0.1 mm., with nucleus and con- tractile vesicle. La,ter, March, 1876, other specimens were observed, from the same locality, apparently merging into forms like those of figs. 23 and 24. '' '*i'-i"'^°"''V VI 3. GEOLOGICAL SURVEY OF THE TERRITORIES. 4 -ATE Sinclwr ar So.. L.th !-»icly Del . -18. AMOEBA RADIOSA. IS - 2L SPONGILLA AMOEBOIDS. 22-26 AMOEBA PP.0 TEUS. PLATE V. PELOMYXA VILLOSA, under the name ot.Amwha villoaa. The upper extremity of the figures corresponds with the forepart of the animal in movement. Magnified 250 diameters, except those specially indicated. Figs. 1, 11, 13, 14 viewed by reflected light ; the others by transmitted light. Fig. 1. Individual from China Lake, Mount Gilbert, Uinta Mountains, Wyoming, August, 1877. The broader part in advance, with projection of a cap of clear ectosarc, into which the granules of the endosarc are seen entering on the left. The posterior extremity with a circular patch of villous pro- cesses. Fig. 2. Individual from a pond, Atco, N. J., September, 1877. The narrow part, in advance, with a thick cap of clear ectosarc. The posterior extremity with a double villous patch, within one part of which three small contractile vesicles are visible. Fig. 3. A smaller individual from the same locality. It presents four small conical pseudopods. Fig. 4. Another individual from the same locality. It terminates in a villous ball. Fig. 5. A more translucent Individual, likewise from the same locality. Fig. 6. Individual from China Lake, Uintas, exhibiting in the interior, mingled with the food, a multitude of sand,.grains. Fig. 7. A small individual from Fort Bridger, Wyoming. The body ending in a vUlous ball. Figs. 8, 9. Two small individuals from the same locality. The former figure exhibits a granular nucleus near the centre, and both present posteriorly a large contractile vesicle. Fig. 10. Individual from a ditch below Philadelphia, September, 1875. Fig. 11. An individual of large size, at rest, from Absecom pond. New Jersey, June, 1874. Mag- nified 33 diameters. The specimen was remarkable for the abundance of quartz sand it contained. Fig. 12. Individual from Hammontoti pond, New Jersey, September, 1877. The posterior villous processes exhibit within a number of small contractile vesicles. Among the food-contents posteriorly a large diatom is observable. Fig. 13. The same specimen as subsequently observed by reflected light. Fig. 14. An individual from a pond on Dr. George Smith's farm. Upper Darby, Delaware County, June, 1874. 85 diameters. As seen by reflected light in movement. The posterior villous ball with a quantity of material adherent and dragged after the animal. Many similar specimens were obtained, varying from 0.25 to 0.75 mm. in length. They were remarkable for the abundance of sand they con- tained. Figs. 15-17. Three small individuals from the same locality. Magnified 350 diameters. Figs. 18, 19. Portion of the contents pressed from the specimen of flg. 11, consisting of granules, clear globules, granular corpuscles with nuclei, linear bodies, and quartz sand. Magnified 500 diameters. U S GEOLOGICAL SURVEY OF THE TERRITORIES PLAT'E V. .'os Leidy, Del AMOEBA VILLOSA. PLATE VI. DINAMCEBA MIEABILIS. Magnified 250 diameters. Figs. 1-3. Threo views of the same individual. Fig. 1. As first seen, in the act of swallowing portion of a desmid {J)idymopnum grevillii). Fig. 2. As observed shortly afterwards, with the nnswal- lowed portion of the desmid detached and rejected. Nearly at the same moment the creature discharged from behind and to the left a portion of a cord of the same desmid, with its segments still conjoined, together with many isolated segments of the same and a few of another desmid {Bamiusina ireiisaonii). In the discharged desmids the internal endoehrome masses are shrunken and turned brownish-yellow. Fig. 3. The animal as it appeared in movement eight hours subsequently. Absecom mill-pond, New Jersey, October, 1876. In fig. 2 the Dinamceba is represented with its transparent ciliated mantle or investment, hut this is not reiireseuted in the others. Fig. 4. An individual swallowing two portions of the desmid Didymoprium, which entered to the left of the posterior papillated extremity. Atco, N. J., September, 1877. Fig. 5. An individual, in motion from right to left, from the same gathering. Viewed by par- tially reflected hght. Fig. 6. An individual closely embracing by its posterior widely expanded extremity a cord of Didymopiium. Found with the preceding. Fig. 7. An individual, from the same gathering, as it appeared in the discharge of a multitude of isolated segments of Didymoprium from three different points simultaneously. The three points are indicated by protrusions of clear ectosarc and a single desmid segment. U S GEOLOGICAL SURVEY OF THE TERRITORIES. Pl- ATE Vi. •Jos Leid/ Del Pnoa Smclair V Son, Lil>\ DlNAfvK. JEBA MIRABILIS PLATE VII. Figs. l-U.— DINAMOEBA MIRABILIS. Fig. 1. Individual coatainiiig, besidos a number of food-balls, a large Closterium which bad been swallowed when one-half of the cell after division was yet in the soft condition and allowed of being doubled on the more consistent portion. The large conspicuous globule situated posteriorly remained for a long time unchanged but was finally discharged. From a cranbeny-bog of Atco, N. J., September 21, 1877. 250 diameters. Fig. 2. The same individual as seen the following morning, September 22. 333 diameters. The spicules or minute oils of the surface had everywhere disappeared. The Closterium had been dis- charged, and the interior was occupied with a multitude of clear globules. The pseudopods were long and pointed and were incessantly changing. The five pseudopods at the fore end, from the short knob to the two blunt ones on its right and the two longer pointed ones on its left, illustrate the mode of production and gradual extension of these temporary organs. Fig. 3. An individual devoid of spicules, moving from right to left, the interior filled with numerous segments of Didymoprium enclosed in drops of liquid. From Absecom pond, New Jersey, June, 1876. 250 diameters. Fig. 4. A small individual of the usual form and appearance. It contains a few segments of Didymoprium, the ordinary food ; and at the posterior part a number cf Email contractile vesicles are seen. Atco, N. J., September, 1877. 250 diameters. Figs. 5-7. Three views of an individual, as it appeared at successive periods during 36 hours. The fore part of the body bristled with pointed pseudopods, while the posterior part was thickly papil- late, but no part of the surface exhibited spicules. In fig. 6, the nucleus is concealed from view ; in fig. 7, the green desmid of the former views has become brown. Absecom Tond, New Jersey, November 4th to 6th, 1874. 300-f . Fig. 8. Individual like the preceding, as observed swimming. From the same gathering. Sep- tember, 1874. 530-1-. Fig. 9. An individual which remained nearly motionless and without pseudopods. The interior occupied with abundance of food-balls and large clear globules, but no distinct contractile vesicle nor nucleus observed. The posterior semicircumference of the body finely ciliate, but the anterior smooth. Atco, N. J., September, 1877. 250-f . Fig. 10. Individual, from the same gathering, containing comparatively little food and exhibiting a distinct granular nucleus. Fig. 11. Pseudopod of an individual, from the same gathering, observed October, 1877. The animal of the usual size, and well filled with food, had the surface of the body finely ciliate, but in addition it and the pseudopods appeared to be covered by minute adherent granules as represented in the figure. 500 diameters. Figs. 12-19 illustrate the series of changes observed in the swallowing and digestion of an Amoeba verrucosa by an A.proieus. From Bristol m.irsh, Pennsylvania, August 27, 1876. 500 diameters. Fig. 12. Amoiba verrucosa, comparatively quiescent, with central contractile vesicle. Figs. 13-19. Successive changes in shape and relative position of A. proteus during the act of swallowing and digesting the former. Fig. 13. ^. jprofcas appro.aching the A. verrucosa, with anterior short diverging pseudopods. Fig. 14. The A. proteus embracing closely the A. verrucosa by a pair of digitate pseudopods, the points of contact of which being marked by the left-hand arrow. Fig. 15. The A. verrucosa swallowed and forming a large sphere within the A. protcus. Fig. 16. The A. ver- rucosa, within the latter, has assumed an oval form, and is contained within a vacuole. The central contractile vesicle, which until now had remained persistent, has become less distinct. Fig. 17. The A. verrucosa has assumed a pyriform shape within a large elliptical vacuole, and its contractile vesicle has disappeared. Fig. 18. The A. proteus in. the act of discharging a diatom, while the A. verrucosa has become doubled on itself. Fig. 19. The remains of the A. verrucosa, seen as five granular balls within the A. proieus. Later these balls disajipeared, and their material appeared to be diffused among the granular contents of the .1. proteus. U S GEOLOGICifL, SURVEY OF THE TERRITORIES. FLATE^m. \ WMf --Ah! ' y ..\ -^\- !^ r^ -k ...i V-^-7y$4^" .Jiis Leidy .L'-.'i 1-11 DIRAMOEBA MIRABILIS. 12. A^10EBA V'ERRUCOSA 13 - 19 AMOEBA PROTEUS s PLATE VIII. Figs. 1-16.— AMffiBA VILLOSA Figs. 1-3. Small individuals, from water of a sph» gnons swamp on Broad Mountain, Soliuylkill County, Pennsylvania; collected September, 1876. 200 diameters. Figs. 1, 2, two views of the same individual. Fig. 3. Another individual in which the miclous appears more distinctly discoidal. Figs. 4-16. Supposed young of Ammla villoaa. In water from a brick-pond near Swarthmore College, Delaware County, Pennsylvania, kept during the winter, and examined February, 1875. Figs. 4-8, 500 diameters. Fig. 4. An individual dragging after it a large spherical alga. Within, it exhibits the nucleus In advance of the position of the contractile vesicle. Fig. 5. Another individual, with two contractile vesicles, and the nucleus posteriorly situated. Fig. 6. An individual with the contractile vesicle in the act of collapse. Fig. 7. Another individual with large contractile vesicle and in advance a small nucleus. Fig. 8 is an outline of the same individual as it first appeared. The green balls within the animals consist of unicellular algse or spores which covered the surface of the water containing the Amasba. The red balls appear to be the same kind of algse changed in color by digestion. Among the contents numerous minute crystals are observed. Fig. 9 n-e. Some of the crystals magnified 1,200 diameters. Fig. 10. An individual, magnified 750 diameters, exhibiting a multitude of crystals among its contents. The nucleus occupies a position just posterior to the contractile vesicle. Fig. 10 a. A crystal magnified 1,200 diameters. Fig. 11. An individual which, after moving about for some time, with the form seen in the pre- ceding figures, spread out in disk-like shape and became very thin. The nucleus to the left, with a reddened algous spore resting against it. 700 diameters. Fig. 12. A resting individual containing u, large nucleus with coarse uniform granules. 700 diameters. Figs. 13, 14. Two views of an individual containing two large and coarsely granular nuclei. Fig. 14 exhibits the mutual compressibility of the nuclei and contractile vesicle, as seen in the move- ments of the animal. 500 diameters. Fig. 15. An individual as it appeared at the moment of collapse of the contractile vesicle and the bursting of one of the nuclei with the simultaneous escape of the granules or spores of the nucleus and the contents of the contractile vesicle. Tlio red bodies are algous cells. 533 diameters. Fig. 16. An individual containing six large granular nuclei, which, together with the equally large contractile vesicle, rolled about among one another in the movements of the animal. 500 diame- ters. Pigs. 17-30.— Supposed young of AMCEBA PEOTEUS. Figs. 17-20. Four individuals, from among a multitude contained in water with Nitella, fur- nished by Mr. Holman in one of his "life-slides," January 8, 1875. The nucleus of variable size. 1,000 diameters. Figs. 21, 23. Two views of an individual. Fig. 23. A second individual. Obtained, together with many others of the same kind, in water from a cow-track in a springy x)lace on Darby Creek, Delaw.are County, Pennsylvania, March, 1876. 500 diameters. Figs. 24-26. Three individuals, observed with m.any others together with large characteristic specimens of Amoeba proteus. From ditch-water, collected in the meadows below Philadelphia, April, 1874. 500 diameters. Figs. 27, 28. Two different individuals, observed in association with the preceding, containing a large tripartite nucleus. Others were observed with the nucleus simple and in various stages of tripar- tite division. 500 diameters. Fig. 29. Individual found in association with those of figs. 21-23, together with others of inter- mediate size. Observed in the act of discharging two diatoms, while nothing else was seen to escape. .Fig. 30. An individual, observed in the act of division. Separation occurried in ten minutes after having noticed the animal as seen in the figure. Subsequently the lower individual escaped, while the upper one was watched and was seen to divide in the same manner as its parent, hut in a direction at right angles to the former one. The offspring assumed a slug-like shape as in figs. 4, 10, 20, 29, and moved away. 500 diameters. The two largest globules to the left in each figure, inadvert- ently colored by tjie lithographer, were colorless and oil-like. Fig. 31. PELOMYXA VILLOSA. An individual which was retained over night in abundance of clear water in an animalcula cage without pressure. It remained nearly motionless, but occasionally protruded a clear lobular portion of ectosaro together with a few pointed pseudopods and shifted its position. The posterior part of the body was minutely papillate. Slight pressure caused the sudden discharge through- a rupture of the ectosarc of some of the contents, consisting of clear globules, granules, a few large nuclei, and numerous linear particles, together with food-materials. From Abse- com pond. New Jersey, August, 1874. 100 diameters. Fig. 32. One of the discharged nuclei, with coarse unifoim gr.anules superficially imbedded. 1,000 diameters. Fig. 33. Granules and linear particles from the same. 1,000 diameters. Fig. 34 a-l. Concretionaiy mineral elements observed in some Amoebas, of the kind represented in figs. 4-lG, aud found in association wi(h them, Febrnai-}-, 1875. 4,000 diaUioters. PLATE VIII Jos I-eidv, L'el 1-16 -AMOEBA VILLOSA 17 - 30. AMOEBA PROTEUS, 01 -33 PELOlvrfXA VILLOSA PLATE IX. Figs. 1-12.— OURAMCEBA VOJRAX. Fig. 1. Individual as seen moving with the narrow end iu advance, and with the tufts of append- ages trailing behind in a widely expanded manner. The interior so completely gorged with food, consist- ing of alg£e, as to completely obscure the nucleus and contractile vesicle. The first specimen observed. From a spring, in which grew water-cross, on Darby Creek, Delaware County, Pennsylvania, May, 1874. Magnified 200 diameters. Fig. 2. Individual from same gathering as seen in movement. Five tufts of caudal filaments trail- ing behind. A discoid nucleus seen in advance of the middle; a contractile vesicle behind. The arrows indicate the direction of motion of the three principal pseudopods. Fig. 3. The same specimen as observed in a contracted spheroidal form. Fig. 4. Specimen from a pond on Darby Creek, Delaware County, June, 1874. Provided with only two tufts of short caudal filaments. The arrows indicate the direction of flow in the different pseudopods. The nucleus and contractile vesicle distinctly seen. 250 diameters. Fig. 5. Specimen from same spring above mentioned, April, 1875. Body of palmate form, with distinct nucleus and contractile vesicle. The caudal filaments widely divergent, and presenting irregu- lar constrictions. The large diatom occupying an extension of the body to the left posteriorly was sub- sequently withdrawn, and was finally seen to be expelled nearly in the same position it now occupies in the figure ; n., nucleus ; j). »., contractile vesicle. 250 diameters. Fig. 6. Another specimen from same locality. Nucleus nearly central. 350 diameters. Figs. 7, 8. Two views of the same individual ; a small specimen from the same gathering as that of fig. 5. With a single pair of long caudal filaments. Nucleus unobserved. 350 diameters. Fig. 9. Another individual, with a pair of short caudal filaments projecting to the right of a mul- berry-hke process of the body. Nucleus just posterior to the middle. 350 diameters. Fig. 10. Two tufts of caudal filaments showing the mode of branching near their origin. Fig. 11. A single detached tuft apparently starting from a button of somewhat consistent pro- toplasm. Fig. 12. Portions of two filaments from the specimen of fig. 1, exhibiting the structure. Ma.gni- fied 400 diameters. Figs. 13-17. OUEAMOEBA BOTULICAUDA. All the specimens from the spring above indicated. Fig. 13. Specimen obtained April, 1875. With three caudal appendages. A nucleus in advance and two contractile vesicles behind. The latter came into contact, united in one, and then collapsed. 500 diameters. Fig. 14. Obtained January, 1878. Body somewhat palmate, containing a nucleus and two con- tractile vesicles, and with four caudal appendages. 730 diameters. Body elongated to 0.06 mm., con- tracted to 0.021 mm. Fig. 15. Specimen with three appendages, obtained May, 1874. 500 diameters. Fig. 16. Specimen with two tufts of appendages. From same gathering. Fig. 17. Specimen obtained with that of fig. 13. Five other specimens were observed at same time, aU with three appendages except one, which had nine appendages. One of the specimens was swallowed by a little worm, Chastogaster, and could be distinctly seen within the stomach. us GEOLOGICAL SURVEY OF THE TERRITORIES. PLATE IX. Jy-iit Em^lair i Soti. L:t 12 OURAMVEBA YORAX. 13-17 0. BQTULICAUDA. PLATE X. DIFPLUGIA PYEIFOEMIS. The shells of most specimens rejjresented, and the same may be said of the other species of Difflii • gia represented in the succeeding plates, are composed of irregular angular particles of quartz sand, •which particles are mostly drawn only in outline. The transverse diameters of the specimens are uni- form except in cases specially indicated. Fig. 1. Individual with pseudopods' protruded; the endosarc bright green. Swarth more brick- pond, May, 1874. 200 diameters. Fig. 2. Individual from the same gathering. The sarcode contracted into a ball, the endosarc of which was bright-green. 200 -1-. Fig. 3. Individual with profuse extension of pseudopods ; the sarcode colorless ; the shell of coarse sand grains. Pond on Darby Creek, Delaware County, Pennsylvania, May, 1874. 100 diameters. Fig. 4. Large individual with profusion of pseudopods; endosarc colored apparently only from the presence of food. Shell comparatively even. Absecom pond. New Jersey, June, 1874. 133 diame- ters. The same gathering contained many like it, ranging from 0.32 to 0.5 mm. in length. Figs. 5, 6. Two specimens; in the one with bright green endosarc; in the other with the endosarc colored brownish centrally. Ditches below Philadelphia, June, 1874. 200 diameters. Figs. 7-12. Individuals from Absecom pond. New Jersey, June, 1874. In all except the last one green coloring matter was absent in the endosarc. 200 diameters. Specimens collected in the same locality the following September and November presented the same appearances. Fig. 7. An uusym- metrical specimen. The shells presented various degrees of uuevenness and proportionate size. Fig. 13. Individual with remarkably uneven shell, composed of coarse sand and a large diatom case. Endosarc centrally brownish. Cranberry-swamp, at Atco,N. J, April 1877. 200 -f-. Fig. 14. Specimen with shell of unusually coarse sand. An abundant variety from a sphagnous bog on Budd's Lake, Morris County, New Jersey, November, 1874. 250 diameters. The same tiud observed in material from a sphagnous bog of Absecom, New Jersey, April, 1875. Fig. 15. Large shell, slightly unsymmetrical, composed mainly of irregular angular quartz sand, but with a few rounded ones (which is very unusual), and a sponge spicule. Empty specimen. 200 diameters. Similar ones from 0.05 to 0.58 in length occasionally found. Fig. 16. Large form, with shell of coarse sand, common in China Lake, Uinta Mountains, Wyo- ming Territory, August, 1877. 250 diameters. Specimens varying from 0.2 to 0.36 mm. in length, with shell of coarse saiid, and endosarc centrally bright green. Fig. 17. Empty shell, composed of comparatively thin angular flakes of quartz. A not nnfre- quent variety. Hammonton pond. New Jersey, July, 1877. 500 diameters. " Fig. 18. Empty shell, composed of narrow rectangular plates, diatom cases, and a comparatively few sand grains. From sphagnum bordering a spring at Swarthmore, Delaware County, Pennsylvania.. 250 diameters. Fig. 19. Specimen with shell composed of sand, diatoms, and spongilla siucules ; the sarcode con- tracted into a baU, and colorless. Absecom pond. New Jersey, November, 1875. 133 diameters. Fig. 20. A simUax specimen from same gathering, with shell of sand aud diatoms, and sarcode colorless. 100 diameters. Large specimens like this and the former, mostly with shell of variable pro- portions of sand and diatoms, and with colorless sarcode, are not nnfrequent in the ponds of sphagnous bogs of New Jersey. Fig. 21. Individual with sheU of rectangular plates and a few coarse sand grains, and with sar- code contracted into a ball. Sphagnous bog of Absecom, New Jersey, November, 1875. 260 diameters. Fig. 22. Small form, with shell composed of clear chitinoid membrane, incorporated with diatoms sand, and dirt, and with yellowish endosarc. • Pond near Egg Harbor, New Jersey, September 1875! 500 diameters. ' Fig. 23. Empty shell of cliitinoid membrane incorporated with large diatoms and dirt. Found with the last. The same form, living, occasionally found in sphagnous bogs of New Jersey. Figs. 24, 25. Fomis occasionally observed in water of the cedar swamp of Absecom, New Jersev Shell of yellowish chitiuoid membrane with incorporated diatoms, sand, and dirt. Sarcode colorless or With brown endosarc. In the individual of fig. 25 it formed an oval, brown encysted ball Fig. 26. Individual with shell of chitiuoid membrane incorporated with thin siliceous plates, and with sarcode attached to the fundus of tho-shell by long pseudopodal threads. Absecom pond. Now J 6r86y . Fig. 27. Individual with shell of black dirt. Absecom pond. New Jersey, October, 18?4 200 diameters. U,S.r;E01XlGlCAL f^URVEY OF THE TERRITORIES. p; \TK V T>.Ts Sinclair i So/v Lith "DIFFLUGIA PYRIFORMIS. PLATE XI. DIFFLUGIA PYEIFOEMIS. The figures exhibit many variations in the also compressed variety, obtained, with multitudes of the same kind, from Swarthmore brick-pond, Delaware County, Pennsylvania. Shells of clear angular particles of quartz sand, with the bright-green endosarc visible through. The differences in the pseudo- pods represent the appearances as actually observed. Magnified from 100 to 110 diameters. Fig. 1. Regular compressed pyriform individual. Length, 0.56 mm. ; greater breadth, 0.28 mm. ; less breadth, 0.18 mm. Figs. 2, 3. Two views of an individual ; the broader, unsymmetrioal. Fig. 4. Broader lateral view of an individual in which the sarcode was contracted into a ball. Breadth, 0.24 mm. by 0.16 mm. Fig. 5. Broader lateral view of an individual, with broad rounded fundus, of compressed pyri- form shape. Breadth, 0.34 mm. by 0.18 mm. Fig. 6. Individual with prominent fundus. Breadth, 0.31 mm. by 0.16 mm. Fig. 7. Individual with conical fundus and nipple-Uke summit. The green endosarc appeared retracted to the fundus of the sarcode. Fig. 8. Transverse section and oral view of the same. Fig. 9. Broader lateral view of an individual with trilobed fundus. Breadth, 0.3 mm. by 0.16 mm. Fig. 10. Broaderlateralviewof acomparativelylongspecimenwithnipx)le-likesnmmit. Breadth, 0.28 mm. byO.16 mm. Fig. 11. Individual with broad trilobed fundus. The peculiar fan-like spreading of the pseudo- pods was due to their extension beneath the inclined sidesof the cell in "Holman's life-slide." A quan- tity of green corpuscles of the endosarc extended into the root of the pseudopods. Breodth of com- pressed shell, 0.32 mm. by 0.18 mm. Figs. 12, 13. Two views of the same individual, the latter reversed longitudinally, exhibiting the broader and narrower sides. Fig. 14. Individual with flat fundus, and with the sarcode contracted into a ball. Breadth 0.28 mm. by 0.16 mm. Fig. 15. Broader side view of a specimen with angular bilobed fundus. Breadth 0.26 mm. by 0.14 mm. Fig. 16. Broader side view of a specimen with rounded bilobed fundus. To the shell a conspicu- ous crystal was attached. Breadth 0.32 mm. by 0.18 mm. Fig. 17. Broader side view of an unsymmetrical individual. The narrower side view was sym- metrical and like that of the succeeding specimen. Figs. 18, 19. Two views of the same individual, the latter reversed, and appearing in the former, with bilobed fundus. Fig. 20. Broader side view of an individual with conical fundus and lateral angular projections. Breadth 0.28 mm. by 0.16 mm. Fig. 21. Broader side-view of an individual with three blunt lobes to the fundus. Breadth 0.28 mm. by 0.16 mm. Fig. 22. Broader side view of an individual with quadrilobate fundus, unsymmetrical. A single long pseudopod extended outwardly as it appeared in a " Holman's life-slide." . Breadth 0.32 by 0.16 mm. Fig. 23. Appearance of clear colorless corpuscles of the endosarc measuring from 0.00266 to 0,00798 mm. PIG. 24. Appearance of the green corpuscles having nearly the same range of size. IJ^S GEOLOGICAL SURVEY OF THE TERRITORIES. PLATE XI s-Leidy Dei Uu h .-.m.Lith DIFFLUGIA PYRIFORmS. 1 - 6 VAR. COMPRESSA 7- 2SVAK. NODOSA,, PLATE XII. Figs. 1-18.— DIFFLUGIA PYRIFORMIS. Fig. 1. Individual with shell of uniform transverse diameters, but with less prolonged neck than usual. The contracted sarcode with bright green endosarc. Absecom pond, September, 1875. 100 diameters. Figs. 2-9. The variety Diffiugia vas distinguished by a constriction in the neck of the shell. Fig. 2. Individual from the same gathering as that of fig. 1. 100+ . Fig. 3. Empty shell of coarse sand grains. Ft. Bridger, Wyoming. Figs. 4-6. Individuals with shell st.iined ' ly ferruginous coloring. Sphagnous bog near Abse- com, October, 1875. 100 diameters. Fig. 7. Small, empty shell, somewhat unsymmotrical and of comparatively even surface. Swarth- moro brick-pond, Ai>ril, 1876. 350 diameters. Fig. 8. Individual with comparatively even shell, and with endosarc mingled green and yellow. Found with the last. 350 +. Fig. 9. Large individual with shell of coarse sand, and with sarcodo contracted into a ball ; the endosarc exteriorly green and centrally yellow. Budd's L.ake, New Jersey, March, 1875. 100 diameters. Figs. 10-16. The variety Diffiugia compressa, in which the shell is broader one way than in the other. Figs. 10, 11. Two views of the same individual in outline. The yellow spot indicates the appear- ance of the endosarc. Spring on Darby Creek, Delaware County, Pennsylvania. 100 diameters. Figs. 12, 13. Two views of an individual. The aarcode retracted but not encysted; the endosarc yellow. From material collected on South Mountain, Burke County, North Carolina. 200 diameters. Fig. 14. Individual with shell composed of coarse sand, uneven surface and slightly-pointed sum- mit. 200 diameters. Breadth 0.22 mm. by 0.112 mm. Figs. 15, 16. Two views of an individual, with shell of coarse sand .and yellow endosarc. 200 diameters. This and the preceding from a pond on Darby Creek, Delaware County, Pennsylvania. Figs. 17, 18. The variety Diffiugia cm-nuta. Both in outline ; 250 diameters. From a bog near Atco, N. J., June, 1877. One with one, the other with two points, and both with colorless sarcode. Figs. 19-21.— DIFFLUGIA CRATERA. Figs. 19,20. Two empty shells composed of chitinoid membrane with incorporated granules of sand. From Bristol Canal, Bucks County, August, 1876. 600 diameters. Fig. 21. Empty shell. Lake Erie, Buffalo, N. Y., August, 1878. 800 diameters. (Since describing these minute forms I have suspected that they belong to a ciliated infusoriau of the genus Tintinnus.) Figs. 22, 23.— DIFFLUGIA URCEOLATA. Common forms in China Lake, Uinta Mountains, Wyoming Territory, August, 1877. 125 diameters. Figs. 24-28.— DIFFLUGIA ACUMINATA. Compressed variety with from one to three spines to the fundus of the shell. Figs. 24-27. Specimens from Swarthmore brick-pond, June, 1874. 350 diameters. Fig. 24. With a single spine ; breadth 0.088 mm. by 0.052 mm. Fig. 25. With a pair of spines ; breadth 0.072 mm. by 0.052 mm. Fig. 26. With two spines of unequallength; breadth 0.064 mm. by 0.048 mm. Fig. 27. With three spines; breadth 0.072 mm. by 0.056 mm. Figs. 28, 29. Two views of the same individual. Fig. 28. Broader view, with pseudopods pro- truded, and animal as observed in the act of swallowing a diatom. Fig. 29. Narrower view. From a ditch below Philadelphia, August, 1874. 200 diameters. In this plate the lithographer has greatly exaggerated the yellow coloring. In figs. 4-6 the shells had a faint fen-uginous tint ; in figs. 8, 9, the color pertaining to the sarcode was browner and duller ; in figs. 15, 16, and 22-28 the color was pale clay colored, and in figs. 19-21 the shell was nearly colorless. U.S. GEOLOGICAL SUPYEY OF THE TERRITORIES PLATE ZIT %% I aS^ ^^ \ (i I f ^^ -'!^S^S-Jfcu>3:-''!^ "^SS^J. fc?\ 'p .Xif^_,M,{ ^i>. r^5' ." y^^ -?■.% ^1 ^ ^%?^ ^?"V^' ^if ^' y i%\ V ->- A./*#-d»-rf *«ikEf \ / - A%:. J J03Leidy,I'»; , ; • •<;>.■, — T^< Sa,cl^, * Son, L.r„ L DIFFLUGLA PYRIFORMIS 2-9 D VAS 10-16 D COMPRESSA, 17, IS D CORNUTA 19-21 D. CR-ATERA 22, 23, D URCEOLATA 24- 2 0. D, ACUMINATA.. PLATE XIII. DIFFLUGIA ACUMINATA. The sliell composed of angular particles of qaartz sand, except in instances especially mentioned ; the Barcode in nearly all colorless, or with a pale clay color to the eudosarc. Figs. 1, 2. Examples of common forms ia Swarthmore brict-pond, May, 1874. Sarcode colorless and commonly entirely obscnied from yiew by the structure of the shell. 200 diameters. Figs. 3, 4. Shells of coarse angular quartz sand. China Lake, Uinta Mountains, Wyoming Terri- tory, August, 1877. Common forms. 250 diameters. Fig. 5. Two individuals in conjugation. The coarse structure of the shell prevented any move- ment of the sarcode from being visible ; the yellowish stain produced by the endosarc. Swarthmore brick-pond. May, 1874. 200 diameters. Fig. 6. Individual with pseudopods protruded. Pond on Mount Gilbert, Uinta Mountains, Wyo- ming, August, 1877. 250 diameters. Fig. 7. Shell of coarse quartz sand. Absecom pond, New Jersey, August, 1876. 200 diameters. Fig. 8. Individual with shell approximating the form of that of Difflugia wreeolata. China Lake, Uiutas. 250 diameters. Fig. 9. Tubular form vrith acuminate summit, not uncommon. Pond on Darby Creek, Delaware County, Pennsylvania, October, 1874. 200 diameters. Fig. 10. Small individual found with others of the same kind among Utricularia from Florida, October, 1874. 200 diameters. Fig. 11. Shell of coarse sand, with a single pointed flake at the acuminate summit. Absecom pond. New Jersey, October, 1874. 500 diameters. Fig. 12. Shell of unusual form, with well-defined neck and mouth surrounded with a distinct rim; also composed of comparatively coarse sand. Found in the same gathering as the last. 500 diameters. Figs. 13-15. From Swarthmorebrick-pond. 200 diameters. Fig. 13, an ordinary form of shell; sarcode with yellowish endosarc ; fig. 14, individual with pseudopods protruded ; fig. 15, individual with pseudopods protruded and with bright green endosarc. The brown spots on the shells of the two latter figures indicate grains of garnet entering into their construction, an unusual occuiTcnce. Fig. 16. Unsymmetrical shell, with unusually large stone adherent on one side. China Lake, Uintas, Wyoming T. 250 diameters. Figs. 17, 18. Shells of chitinoid membrane with incorporated sand. Pond at Atco, N. J., August, 1876. 250 diameters. Fig. 19. Shell of chitinoid membrane, with incorporated sand and diatom fragments. Absecom pond, New Jersey, August, 1876. 250 diameters. Figs. 20-22. Drop tube-like forms. Absecom pond. New Jersey. 200 diameters. Fig. 20. Indi- vidual with unusually and remarkably rough shell, composed of sand ; September, 1875. Fig. 21. Shell remarkably uneven, composed of chitinoid membrane with incorporated sand and diatoms ; October, 1874. Fig. 22. Shell of chitinoid membrane with incorporated sand and diatoms; found in company with the last. Figs. 23-26. Shells of chitinoid membrane incorporated with diatoms ; 23-25 empty, and the for- mer with sand at the border of the mouth ; 26, with the sarcode encysted. From sphagnum of Abse- com cedar swamp, October, 1874. 500 diameters. IIS GEOLOGICAL" SURVEY OF THE TERRITORIES. PLATE Xin mm.-^ Jcd Leidy.Es]. DIFFLUGIA ACUMINATA. :7iOB Sir,^l(.ir A Sop. Lit PLATE XIV. DIFFLUGIA UECEOLATA. All tlie figures were taken from living specimens, represented in t'aeir usual iiosition, and willi tte shells composed of angular particles of quartz sand. Fig. 1. Variety approaching Difflugia acuminata. 200 diameters. Swarthmore hrick-pond, Dela- ware County, Pennsylvania, October, 1875. Fig. 2. Variety with less acuminate fundus to the shell. 250 diameters. Lake of Uinta Mount- ains, Wyoming, August, 1877. Fig. 3. Variety Difflugia amphora. 100 diameters. Ditch below Philadelphia. Common form. Fig. 4. Oral view of a similar specimen. Fig. 5. Characteristic specimen of Difflugia ureeolata. 200 diameters. Absccom pond, New Jersey, August, 1876. Common form. Fig. 6. Narrower variety of the same kind occurring with it. Fig. 7. Common form in ditches communicating with the Delaware River below Philadelphia. Fig. 8. Common form ; abundant in a pond of Bridger Butte, Fort Bridger, Wyoming, August, 1877. 250 diameters. Fig. 9. Acuminate variety, with additional spines to the fundus. A not unfrequent form. Atco, N. J., September, 1877. 250 diameters. Fig. 10. Common variety. Absecom pond. New Jersey. 250 diameters. Fig. 11. Variety named Difflugia olln. Abundant in the ponds of sphagnous swamps. Budd's Lake, Now Jersey, September, 1874. 250 diameters. The sarcode encysted. Fig. 12. Unsymmetrical specimen. Absecom pond, New Jersey, September, 1875. 200 diameters. Fig. 13. Many-spined specimen, found with the former. 200 diameters. Each spine ending in a single large sand grain. Fig. 14. Single-spined specimen. Atco, N. J., September, 1877. 250 diameters. The spine end- ing in a single large sand grain. U S GEOLOGICAL SURVEY OF THE TERRITORIE "PLATE XP/ TKos Siaclsir ^ ? ir . DIFFLUGL^ URCEOLATA PLATE XV. Figs. 1-24.— DIFFLUGIA LOBOSTOMA. Figs. 1, 2. Two views of the same individual ; the shell composed of coarse quartz sand ; endo- sarc centrally bright green ; the pseiidopods protruded. Fig. 1, inferior view exhibiting the trilobed mouth ; fig. 2, lateral view. Swarthmore brick-pond, June, 1874. 200 diameters. Figs. 3, 4. Similar views of another specimen found with the former. Figs. 5, 6. Similar views of an empty shell with qu.adrilobate mouth. Pond near Darby, Dela- ware County, Pennsylvania, October, 1874. 250 diameters. Fig. 7. Lateral view of an individual, with trilob.ite mouth and projecting rim. Ditch below Philadelphia, May, 1875. 250 diameters. Fig. 8. Inferior view of an individual with quadiilobate mouth and colorless sarcode.. China Lake, Uinta Mountains, Wyoming Territory, August, 1877. Length, 0.18 mm. ; breadth, 0.16 mm. Fig. 9. Inferior view of an individual with quinquelobate mouth and colorless sarcode. Fort Bridger, Wyoming, August, 1877. 200 diameters. Length, 0.112 mm. ; breadth, 0.1 mm. Fig. 10. Inferior view of an individual -with six-lobed mouth, the margin stained brown. Fig. 11. Side view of the same with remarkable pscudopodal extension. Ditch below Philadelphia. Fig. 12. Inferior view of a similar individual. Fort Bridger, Wyoming Territory, July, 1877. Length, 0.14 mm. ; breadth, 0.13 mm. Fig. 13. Side view of au individual with a seven-lobed mouth. Apjjearauce of the pseudopod, spread out beneath the edge of a Hohnan life-slide. Found with the preceding. Fig. 14. Inferior view of au individual -with seven-lobed mouth ; the sand grains of the shell out- lined with brown cement. Darby Creek, Delaware County. 250 diameters. Length, 0.14 mm. ; breadth, 0.12 mm. Fig. 15. Small individual with trilobed mouth, inferior view, with profuse extension of pseudo- pods. Ditch below Philadelphia, April, 1876. 200 diameters. Length, 0.055 mm. ; breadth, 0.05 mm. Figs. 16, 17. Two views of an empty shell, composed of rectangular and oval plates with dotted intervals; fig. 10, inferior view exhibiting the quadrilobate mouth; fig. 17, lateral view showing pro- jecting rim of the mouth. China Lake, Uinta Mountains, Wyoming Territory, August, 1877. 500 diameters. Figs. 18, 19. Two views of au empty shell, composed of rectangular plates and fragments of dia- toms; fig. 18, inferior view, exhibiting au irregular multilobate (probably mutilated) mouth ; fig. 19, lateral view. Hammouton pond, New Jersey, September, 1877. 250 diameters. Fig. 20. Lateral view of a specimen with trilobed mouth, composed of thin angular plates and diatoms. Atco, N. J. , June, 1877. 250 diameters. Figs. 21, 22. Inferior and lateral views of a mamnullated specimen with six-lobed mouth bordered by a projecting rim. Woodstown pond, New Jersey, September, 1877. 250 diameters. Figs. 23, 24. Inferior and lateral (reversed) views of a small heniispheroidal specimen, with five- lobed mouth. Swarthmore brick-pond. 250 diameters. Figs. 25-31.— DIFFLUGIA 6L0BUL0SA. 250 diameters. Figs. 25, 26. Two views of the same individual, with colorless sarcode, except the color due to food iu the endosarc; fig. 25, lateral view ; fig. 26, inferior view exhibiting the circular mouth. Swarth- more brick-pond. Figs. 27, 28. Two views of the same individual, with colorless sarcode and extended pseudopods ; fig. 27, lateral view showing a projecting rim to the mouth ; fig. 28, inferior view 8ho^ving the large circular mouth. Fort Bridger, Wyoming, August, 1877. Figs. 29, 30. Two similar views of a specimen. Ditch below Philadelphia, September, 1875. Fig. 31. Lateral view of an individual, with the shell composed of chitinoid membrane, iiTcgn- larly striated and incorporated with a few scaMerod sand grains. A single pseudopod enormously extended. Pond near Darby, Delaware County. Figs. 32, 33.— DIFFLUGIA PYRIFORMIS. 200 diameters. Two individuals showing their approximation iu shape to the snbpyriform varieties of Difflugia globwlosa. Sw.arthmore brick-pond. Figs. 34-37.— DIFFLUGIA AECULA. 250 diameters. Figs. 34, 35. Two views of an empty shell, composed of olay-oolorod chitinoid membrane ; fig. 34, lateral view, with sand grains incorporated at the fundus; flg. 35, inferior view showing the trilobate mouth. Sphagnous bog of Absecom, N. J., April, 1876. Figs. 36, 37. Two similar views of a specimen composed of chitinoid membrane with incorporated sand and dirt. Toliyhauua sphagnous swamp, Pokono Mountain, Pennsylvania, July, 1876. U.S^ GEOLOGICAL SURVEY Of T'HE TERRlTfiRI:ES. PLATE XV Sofc Sinoia-.r ft Sjn. L.i 14 DIFFLUGIA LOBOSTOMA. 26-31 D.GLOBULOSA. 32- 33 D .PYRIFCRMIS.34- 37 D.ARCULA PLATE XVI. Figs. 1-24.— DIFFLUGIA GLOBULOSA. Figs. 1,2! Two viewH of an empty shell, composed of coarae quartz sand; fig. 1,' inferior view sliowins the circular mouth ; lig. 2, lateral view. Absecom mill-pond. 200 diameters. Figs. 3, 4. Two views of a large specimen, found with the preceding ; magnified 100 diameters. Figs. 5, 6. Two views of a specimen with yellowish tint. Uinta Mountains, Wyoming. 200 diameters. Figs. 7, 8. Corresponding views of a living individual. Ditch below Philadelphia. 200 diameters. Figs. 9, 10. Similar views of a specimen, in which the shell is composed of chitinoid membrane incorporated with narrow rectangular plates, etc., and the sarcode contracted into an encysted ball. China Lake, Uintas, Wyoming, August, 187r. 200 +. Figs. U, 12. Inferior and lateral views of a small shell, composed of sand. Sphagnous swamp, Absecom, N.J. 200 +. Figs. 13, 14. Same views of a small shell composed of chitinoid membrane incorporated with sand. A continuous circle of sand grains surrounds the month. Sphagnous swamp, Broad Mountain, Pennsyl- vania. 200 -f . Figs. 15, 16, 17. Inferior, lateral, and superior views of a small shell composed of chitinoid mem- brane with scattered sand grains. Pond near Cape May, N. J. 200 +. Figs. 18, 19. Lateral and inferior views of a minute shell, composed of chitinoid membrane, striated and incorporated with scattered sand particles. An accnmnlation of the latter occupies the fundus. Pokono Mountain, Pennsylvania. 500 -f-. Fig. 20. Inferior view of a living individual, with shell of sand, and with colorless sarcode. Fort Bridger, Wyoming Territory. 250 diameters. Shell of oval form 0.08 mm. long ; 0.068 mm. broad. Fig. 21. Inferior view of an empty shell, composed of chitinoid membrane incorporated with large diatoms, etc. Sphagnous swamp, Absecom, N. J. A not unfrequent kind. ,'00 -f. Shell hemispheroidal, 0.036 mm. high ; 0.058 mm. broad. Fig. 22. Similar view of a specimen composed of rectangular plates, together with a few diatoms. If'ound with the preceding and likewise not an unfrequent kind. Height, 0.032 mm. ; breadth, 0.054 mm. Fig. 23. Inferior view of an individual in which the shell was composed of brown chitinoid mem- brane incorporated with sand and dirt. Boggy place near Swarthmoro, Delaware County, Pennsylvania. 500 -f-. Shell 0.032 mm. high ; 0.05 mm. broad. Fig. 24. Inferior view of a specimen in which the shell was composed of sand with intervening brown cementing substance. Psendopods numerous and more branching and pointed than usual. Same locality as the preceding. 500-(-. Shell 0.33 mm. high ; 0.05 ram. broad. Figs. 25-29.— DIFFLUGIA LOBOSTOMA. Figs. 25, 26. Two views of an individual in which the shell appeared to be composed of yellowish, cancellated chitinoid membrane as in the genus Nebela : fig. 25, lateral view, with sarcode seen attached by threads to the inside of the fundus of the shell. A large central nucleus and several contractile vesicles situated at the periphery are also visible. Fig. 26, inferior view exhibiting the trilobate mouth and protruding pseudopods. Among Duckmeat in a ditch below Philadelphia, June, 1874. 500 -f . Figs. 27, 28. Inferior and lateral views of a living individual, in which the shell was composed ot colorless chitinoid membrane with a few scattered sand particles. Swarthmore brick-pond. May, 1874. 333 diameters. Fig. 29. Lateral view of a living specimen, in which the shell was composed of chitinoid mem- brane with incorporated floccnlent dirt, and in which the mouth was trilobed. Boggy place on Daiby Creek, Delaware County. 200 -f . Figs. 30, 31.— DIFFLUGIA AECULA. Inferior view of two empty shells of hemispheroidal shape, composed of yellow chitinoid mem- brane incorporated with brownish dirt and a few scattered particles of sand. (The unsymmetrical outline of fig. 30 correct, though probably accidental.) Sphagnous swamp of Atco, N. J. 250 diame- ters. The shells shaped like that of an ordinary sea-urchin. Height of shell, 0.072 ram. ; breadth, 0.136 mm. to 0.14 mm. Figs. 32-34.— DIFFLUGIA URCEOLATA. Fig. 32. Variety Difflufjia olla. Lateral view of a living individual with protruded pseudopods. Absecom pond, New Jersey, October, 1875. 100 -|-. Fig. 33. Egg-shaped variety, with a, narrow jarojecting rim to the mouth. Lateral view of a living specimen. A common form in a pond on Bridger Butte, near Fort Bridger, Wyoming Territory, August, 1877. 250 diameters. Fig. 34. Variety Diffiugia amphoi-a. Lateral view with pseudopods extended. Common in the ditches below Philadelphia, October, 1875. 100 diameters. Fig. 35.— DIFFLUGIA CKATERA. Lateral view of an empty shell composed of chitinoid niembram^ incmporated with fine sand par-' tides. Lake Erie, Buffalo, N. Y., October, 1878. 500 -|-. Fig. 36.— DIFFLUGIA f Lateral view of an empty jiyriform shell possessing two long di veri;<'ut appendages, and composed of colorless chitinoid membrane incorporated with irrogulai' angular quartz particles. The only speci- men of the kind observed. Sphagnous swamp, Atco, N. J. 250 -|-. Figs. 37, 38.— DIFFLUGIA PYEIFORMIS. Fig. 37. Subpyriforui variety approximating Diffiugia gJohuJosa. L.atcral view of a living speci- men, the shell of which composed of angular quartz sand with a comparatively large grain attaclied to the fundus. Ditch below Philadelphia, March, 1875. 100 +. Fig. 38. Lateral view of an individual, from one side of the shell of which there projects unsym- metrically a comparatively large stone. Boggy place on Darby Creek, Delaware County, Pennsylvania. 100 diameters. Fig. 39. Nucleus pressed from an individual of Diffiugia lohonioma, October, 1674. 500 diameters. Figs. 40, 41. Isolated nucleus, and portion of crushed material from an individual of Difflugia urceolala. 500 diameters. ^^^^^^^^-' SURVEY U^^^SSS. 34. 1) UROEO^A.-A 35 D CRATERA 86-41. D.'FFLUGIA PLATE XVII. DIFFLUGIA COEONA. All the figureB were from living specimens ; the shell composed of angular quartz sand and the sarcode colorless. 200 diameters, except 'whon specially indicated. Fig. 1. Individual with extended pseudopods ; the shell with seven spines to the 'fundus, of which five are visible in the lateral view. The month was furnished with twelve points or teeth and as many Intervening sinuses. The somewhat palmate pseudopods were spread outwardly on the inclined border of a glass cell. A common form in Swarthmore brick-pond, Delaware County, and iu ditches below Philadelphia. Figs. 2-4. Common forms, from Lake Hattacawanna, Morris County, New Jersey, October, 1874. Fig.-2, lateral view of an individual with extended pseudopods ; shell with seven spines to the fundus and fifteen teeth to the mouth. Fig. 3. Inferior view of another individual, exhibiting the month and extended pseudopods. Shell with seven spines to the fundus .ind fourteen teeth to the mouth. A.similar specimen, 0.248 mm. high and 0.24 mm. broad, had seven spines to the fundus and twelve teeth to the mouth. Fig. 4. Upper view of a specimen with eleven spines to the fundus. Mouth O.IC mm. in diameter with sixteen brown teeth. As represented in the figures, while the body of the shell is colorless, the spines and border of the mouth are frequently stained of a ferruginous brown. Figs. 5, 6. Two views of the same individual ; fig. .5, lateral view, with extended pseudopods, and four spines to the fundus ; fig. 6, inferior view exhibiting the mouth with fifteen teeth. Ditch below Philadelphia, September, .1875. Fig. 7. Lateral view of a specimen with an oblique mouth as in Difflugia constrkta, bnt furnished with twelve teeth, and having a single spine to the fundus. The only specimen of the kind seen. Swarthmore brick-pond, March, 1875. Fig. 8. Inferior view of a specimen exhibiting the mouth with six teeth. The fundus of the shell had seven comparatively short spines. Jacksonville, Fla., March, 1875. Fig. 9. Liiteral view of a slightly unsymmetrical specimen with a single spine to the fundus. The mouth had twelve teeth. Ditch below Philadelphia, September, 1875. Fig. 10. Lateral view of .an individual with a pair of widely divergent spines to the fundus, and with extended pseudopods. Mouth with twelve teeth. With the preceding. Fig. 11. An unusually unsymmetrical specimen. Lateral view with extended pseudopods. Seven spines to the fundus and sixteen .teeth to the mouth. Atco, N. J., September, 1877. Fig. 12. Six-lobed mouth of a specimen which had seven spines to the fundus. The shell was 0.33 mm. in di.ameter. Lake Hattacawanna, New Jersey. Fig. 13. One of the spines ii-om the same specimen, showing a liince-head-Uke flake n.t the end. 375 diameters. Fig. 14. Three teeth from a specimen like that of tij;. 6, showing terminal colored sand grains. U.S. GEOLOGICAL SURVEY OF THE TERRITORIES. LATE XVI ; ■^'?/^.; 2l^..^^l^ h F „i L,i DIFFLUGIA . CORONA. PLATE XVIII. •DIFPLUGIA CONSTKICTA. In the lateral views of the specimens, they occupy the natural position with the mouth downward and on a level ; in the posterior views, they are tilted upward or appear as ordinarily seen, lying on the front beneath the microscope. Anterior views appear the same as the latter, as the mouth is visible through the front wall of the shell. The shell mostly composed exclusively of angular quartz sand, and the sarcode colorless. Fig. 1. Lateral view of an individual with psoudopods protruded. Ditch below Philadelphia, June, 1877. 500 diameters. Figs. 2, 3. Two views of the same specimen ; the former posterior, the latter lateral (inadvertently misplaced by the artist ; the inclined line on the right should have been horizontal). From moss in the fork of an apple tree, Swarthmore, November, 1877. 250 diameters. Figs. 4, 5. Lateral and posterior views of the same specimen. Sphagnous swamp, Vineland, N. J., September, 1876. 250 +. Figs. 6, 7. Lateral and posterior views of the same (the former misplaced by " the artist ; the inclined line on the left should be horizontal). Fort Bridger, Wyoming Territory, July, 1877. 250 -f-. Figs. 8, 9. Posterior and lateral views of a shell composed of yellowish chitinoid membrane, incor- porated with scattered sand, and a continuous circle of grains around the mouth. Found with that of figs. 2, 3. 250+. Fig. id. Posterior view of a shell composed of chitinoid membrane with sand and dirt. From among moss in the crevices of the pavements of Philadelphia, June, 1S78. 333 -f . Figs. 11, 12. Posterior and lateral views of an individual with extended pseudopods. Shell as in the preceding. From among moss of the pavement in the yard of my house, June, 1878. 333 4-. Fig. 13. Posterior view of the same specimen in the natural position, or not tilted forward. " Fig. 14. Lateral view of a specimen, with shell composed of sand and with projected pseudopods. A frequent form found with the preceding. 333 +. Figs. 15, 16. Posterior .and lateral views of a shell of chitinoid membrane with sand grains. Per- haps pertaining to Ccniropyxis ccornis. Found with that of figs. 2, 3. 250 +. Figs. 17, 18. Lateral and posterior views of a shell, comijosed of sand, stained brown, with a darker cement. Fig. 19. Posterior view of another specimen. Mouth of a cave on Bushkill Creek, E.aston, Pa., July, 1878. 333 +. Figs. 20, 21. Lateral and posterior views, with shell of chitinoid membrane incorporated with sand, diatoms, etc. China Lake, Uinta Mountains, August, 1877. 250 -j-. Figs. 22, 23. Posterior and lateral views. (Correct outlines ; with no constriction nor abrupt projection of the fore-lip.) Egg Harbor, N. J., August, 1878. 333 -f . Figs. 24, 25. Posterior and lateral views. With the preceding. 333 -f . Figs. 26, 27. Posterior .and lateral views of a spficimeu with shell of chitinoid membrane, incor- porated at the fundus and around the mouth with sand grains. Sphagnous bog at Absccom, N. J., April, 1876. 250-J-. Fig. 28. Lateral view of shell, tilted uj) to a perpendicular line, composed of chitinoid membrane with large sand grains on the fundus. With the last. 500 -f . Figs. 29, 30. Posterior and lateral views of a specimen with shell of yellow chitinoid membrane, incorporated with sand. A contiuuous circle of grains surrounds llie month, and comparatively large grains occupy the fundus. Absecom pond, April, 187.">. 250 -)-. Figs. 31, 32. Posterior and lateral views of a shell of chitinoid membrane with incorporated sand. Sphagnous bog of Broad Mountain, Pennsylvania, September, 1876. 250 -f . Figs. 33,34. Lateral and posterior views of a similar specimen. Vineland, N. J., September, 1877. 250 +. Figs. 35,36. Lateral and posterior views of a large shell, comjiosed of quartz sand. Vineland, N. J., September, 1877. 175 -f-. Figs. 37-44. Empty shells composed of yellow chitinoid membrane, incoriiorated with variable proportions of scattered sand grains and dirt. Sphagnum of Absecom cedar swamp. New Jersey. Figs. 37, 39, 42, lateral views; tigs. 38, 40, 43, posterior, tilted up, views; figs. 41, 44, posterior views in the normal position. 250 +. Fios. 45, 46. Lateral and posterior views of a large individual with shell of quartz sand, acumi- nate at the fundus, and with extended pseudopods. Vineland, N. J., September, 1877. 175 -\,. Figs. 47, 48. Lateral and posterior views of a large two-spiued shell. Absecom pond, Now Jersey. Fig. 49. Posterior view of a three-spined specimen. With the last. 175 +. Figs. 50, 51. Posterior and lateral views of a two-spined individual. Wind Gap, Northampton County, Pennsylvania. 175 -f. Fig. 52. Posterior view of an individual, with shell having a row of five spines to the fundus, and with a long, bifid pseudopod. Absecom, September, 1674. 175 +. Fig. 53. Posterior view of an individual, with shell having six spines to the fundus, and exhibit- ing a single long pseudopod. Found with the preceding. 175 -f . Fig. 54. Posterior view of another specimen, with four spines. With the preceding. 175 -\.. Fig. 55. Lateral view of tig. 53. Figs. 56, 57. Two spines, showing the lance-hcad-like flake at their termination. 500 +. hLATE X,':JJ •'03 i.ejdy, Dol Tnob Sji-l9ira.iJn.LitK. .HFFLUGIA CONSTRICTA. PLATE XIX. Figs. 1— 23.— DIFFLUGIA SPIRALIS. Figs. 1, 2. Broader lateral, and anterior narrower views of the same individual, with shell of quartz sand and with extended pseudopods. Swarthmore brick-pond, September, 1874. 200 diameters. Fig. 3. Broader lateral view of a pair of individuals in conjugation. Ditch below Philadelpliia. September, 1875. 200 +. Fig. 4. Broader lateral view of a shell composed of rectangular plates, with diatoms, and cen- trally with large angular particles of quartz sand. Hammonton pond, New Jersey, Seirtembcr, 1877. 250 -f. Fig. 5. Lateral view of an individual with extended pseudopods ; the shell composed of quartz sand, except contiguous to the mouth where it is formed of vermicular pellets. From ditch of a cran- beiTy-bog, Atco, N. J., October, 1877. 250 +. Fig. 6. Broader lateral view of a small specimen, with shell of quartz sand. Pool at Manayunk, Philadelphia. 200 -f. Fig. 7. Broader lateral view of an individual, with extended pseudopods, and shell entirely com- posed of short vermicular pellets. A frequent kind in Abseoom pond, October, 1874. 250 +. Fig. 8. Similar view of an individual, with a profusion of pseudopods. The shell composed as in the last, but with the vermicular pellets separated by narrow intervals, occupied with cementing sub- . stance. Found with the former, but only a few of the kind observed. Figs. 9, 10. Posterior and Lateral views of a specimen in w^hich the shell is composed of vermicular pellets, as in fig. 7. Some of the pellets seen to project at the border. The interior contained an oval brownish ball, probably the much reduced .ind contracted sarcode. Sphagnous swamp, Absccom, N. J., March, 1875. 250 -f. Fig. 11. Broader lateral view of an empty shell composed of vermicular pellets and a few large particles of sand. Same locality, June, 1877. 250 -j-. Fig. 12. Individual with shell apparently formed by a net with small angular meshes, and incor- porated with' a few large sand grains. Absecom pond, October, 1874. 250 diameters. The structure as represented I have suspected to be illusory, and to have been really as in fig. 8, but of this I am by no means positive. I have seen no more of the kind since the above date. Fig. 13. Individual with shell of chitihoid membrane incorporated with scattered sand grains. The outline of the sarcode mass is seen within, ending below in the projecting pseudopods. Absecom pond. 225 +. Figs. 14, 15. Broader side view of two individuals, with the shell composed of narrow rectangular plates arranged in all directions and in close juxtaposition. The outline of the interior sarcode visible with its extension to the mouth of the shell. Same locality. 250 -|-. Fig. 16. Small individual, with shell composed of chitinoid membrane incorporated with minute rods. It contains two balls : one oval and colorless, probably the sarcode ; the other globular and colored, probably discharged remains of food. Same locality. 250 -1-. Figs. 17, 18. Posterior and lateral views of an empty shell composed of chitinoid membrane incor- porated with scattered diatoms. Sphagnum of Absecom, October, 1874. 250 -f-. Fig. 19. Broader lateral view of a shell composed of chitinoid membrane, iucoi'porated with scat- tered rods, diatoms, and sand. Absecom pond. 250 -(-. Fig. 20. Specimen with shell composed as in the preceding, and containing four balls, of which, the two colorless ones appeared to consist of the sarcode, while the colored ones were supposed to con- sist of discharged excrement. Found in company with the former. 250 +. Figs. 21, 22. Posterior and lateral views of an empty shell, with unusually long neck, and com- posed nearly as iutho preceding specimens, with which it was obtained. 250 -f . Fig. 23. Broader lateral view of a shell composed of elements of undetermined character. Abse- com pond, June, 1b77. 250 -J-. Figs. 24-26.— DIFFLUGIA PYEIFORMIS. The shell of coarse quartz sand, and with a slanting consti'iction at the root of the neck, so as to give it an appearance approximating that of Difflagia spiralis. Swarthmore brick-pond, September, 1874. 200 +. Others of a similar character found at the same time. Sarcode colorless, except a clay-colored hue to the eiidosarc. Most specimens also exhibited a black p.atch, probably due to some peculiar food. Figs. 27-29.— DIFFLUGLA URCEOLATA. Fig. 27. Small individual, with shell of chitinoid membrane incorporated with diatoms and sand, and with an unusually irregidac surface. China Lake, Uinta Mountains, Wvomins Territory, August. 1877. 250 -f. > J b J, 6 , Fig. 28. Variety Diffiugia olla. Lateral view, with shell composed of coarse sand, and with pro- jected pseudopods. Absecom pond. New Jersey. 200 -f. Fig. 29. Variety Diffiugia olla. Lateral view of .an empty shell, composed of chitinoid membrane incoqjorated with (li.atoms, etc. Found in the siime locality as the preceding. 200 +. US GEOLOGICAL SURVEY OF TIIf! TERRITORIES^ PLATE ;■:[>' T.? LeiAyl'si, 1 - 2 8 Dl F?"'L,UGIA S]-''IRALIS . 24 - 26 D . F'fRIFORMIS , 27 . 29 . D . UR CE ULATA PLATE XX. Figs. 1-10.— HYALOSPHENIA CUNEATA. Fig. 1. Broader lateral view of an individual with a pair of projected pseudopods. The attach- ment of the interior pseudopodal threads produces indentations of the delicate shell. Spring at Lans- downe station, Delaware County, Pennsylvania, April, 1875. 500 diameters. . Fig. 2. Broader lateral view of another individual from the same locality, January, 1878. Fig. 3. Transverse section of the same. 666 diameters. Figs. 4, 5. Broader and narrower lateral views of an individual, from the same locality, June, 1874. 666 diameters. Figs. 6-10. Series of views of a pair of individuals in conjugation exhibiting successive changes in the sarcode. Same locality as the preceding, June, 1874. £00 diameters. Figs. 11-18.— HYALOSPHENIA TINCTA. 500 diameters. Fig. 11. Empty shell, showing minute apertures at the margin, indicated by the arrows a. Sphagnum, Atco, N. J. Fig. 12. View of the broader side of a Uvirig individual, showing the retraction of the sarcode from the mouth of the shell while pseudopods are yet projected. Fig. 13. Transverse view of the same. Sphagnous swamp, Tobyhanna, Poliono Mountain, July, 1876. Fig. 14. Broader side view of an individual, with projected pseudopods. Fig.. 15. Transverse section of the same, with the mouth. Figs. 16, 17. Broader and narrower lateral views of another individual, with pseudopods with- drawn. Siime locality as the preceding. Fig. 18. Small empty shell, showing minute apertures at the border. Same locality. Figs. 19-29.— HYALOSPHENIA ELEGANS. 5C0 diameters. Figs. 19-21. — From the same individual. Fig. 19. Broader lateral view, showing the interior sar- code attached by pseudopodal threads, and with projected pseudopods. Fig. 20. Narrower lateral view of the shell, showing the cup-like depressions. Fig. 21. Transverse view, with the mouth. Sphagnum, Absecom, N. J., October, 1874. ' Fig. 22. Broader lateral view of an individual with ample sarcode and projected pseudopods. jp. r. contractUe vesicles. With the preceding. Fig. 23. Broader lateral view of an individual with projected pseudopods. The sarcode exhibits at its periphery four cdutractile vesicles ; and the nucleus is eccentric. 3readth of shell 0.064 mm. by 0.032 mm. Absecom, May, 1877. (The lithographer has erroneously colored the sarcode.) Fig. 24. Broader lateral view, reversed, with the sarcode contracted into an ovoidal ball ; and exhibiting in the neck a number of round balls, supposed to be excrementitions and discharged from the sarcode. Sphagnum,' Swarthmore, Delaware County, April, 1877. Fig. 25. Specimen containing isolated corpuscles, probably spores or germs, resulting from the segmentation of the original sarcode. Sphagnum, Absecom, October, 1874. Fig. 26. Narrower Lateral view of the shell of the same. Fig. 27. Individual with the sarcode in an encysted condition. A frequent form and condition in sphagnum of Schooley's Mountain, New Jersey, October, 1874. Fig. 28. Specimen- with encysted sarcode. The aiTow a points to one of the minute apertures of the shell. Absecom, N. J., April, 1876. Fig. 29. Specimen with encysted sarcode. The mouth of the shell closed with a number of balls discharged from the sarcode. A frequent condition at Absecom, N. J., November, 187 ,. >j3 Leidy, 1)61 1-10 HYALOSPHEN lA CUNEATA^ 11-18 H TINCTA. 19-29 H ELEGANS PLATE XXI. HYALOSPHENIA PAPILIO. 500 diameters. ' Fig. 1. Broader lateral view of an individual in the normal position, with projected psendopods, and in the act of discharging excrementitous matter. The sarcode nearly filling the shell ; the large granular nucleus visible in the fundus, and contiguous to it four clear contractUe vesicles. Abundant form in sphagnum of most localities in the United States. Specimen from cedar swamp, Absecom, N. J., May, 1877. Fig. 3. Outline of the narrower lateral view of the following. Fig. 3. Broader lateral view of an individual with protruded psendopods. Found with that of fig. 1. Fig. 4. Individual in which the sarcode is much reduced in extent, probably from deficiency of food. Three isolated green corpuscles are seen in the space between the sarcode and shell. Sphagnons swamp, Tobyhanna, Pokono Mountain, July, 1876. Figs. 5, 6. Two views of the same individual, with the sarcode retracted from the mouth of the shell. Sphagnum, New Jersey, May 1877. Figs. 7, 8. Two views of the same individual, with the sarcode contracted into a discoid ball. Absecom, October, 1874. Fig. 9. Narrower lateral view of an individual with encysted sarcode, and with the mouth of the shell closed by contraction and by an operculum. With the preceding; Fig. 10. Broad view of a, similar specimen ; the mouth of the shell not closed. The sarcode encysted. The two brown balls consist of discharged excrementitous matter. Absecom swamp, Octo- ber, 1874. Fig. 11. View of broader side of a specimen ; the mouth of the shell closed by aji operculum ; the sarcode encysted. Sphagnum, Swarthmore, Delaware County, Pennsylvania, October, 1875. Fig. 12. "View of a specimen, containing numerous green corpuscles. From sphagnum of Abse- com, preserved in a glass case during the winter. The specimen observed December, 1874. Many simi- lar ones observed, with variable quantities of green corpuscles, which are suspected to be germs or spores derived from the breaking up of the encysted sarcode. Fig. 13. Specimen of a kind repeatedly observed. Shell containing colorless granular corpuscles. These occur of varied size and in variable quantity. Undetermined whether to be tho spores of the Hyalosphenia, or whether they are parasitic. Sphagnum, New Jersey, April, 1877. Figs. 14, 15. Transverse sections, exhibiting the form of the mouth, and the attachments of the saicode mass to the interior of the shell. ,1.1 3. GEOLOGICAL SURVEY OF THE TERRiTORlES. F'LATE XXJ .mlaaiS;.. I-.' ■Joa Leidv, Del HYALOSPHENIA PAPILIO PLATE XXII. NEBELA COLLAEIS. 500 diameters. From sphagnum of the sphagnous and cedar swamps of New Jersey. Fig. 1. Broader lateral view of a living individual in the normal position, with pseudopods extended. Shell composed mostly of nearly uniform oval plates. Figs. 3-4. Three views of the same individual : — 2. broader lateral view, with interior sarcode and extended pseudopods ; 3, outline of naiTower lateral view ; 4, outline of transverse section with view of the mouth. Shell composed of regular ciicular disks. Figs. 5, 6. Two views of the same : — 5, narrower side ; 6, broader side, containing a number of unequally round and oval granular, clay-colored balls. Shell composed of larger oval plates, with intervening minute round and narrow rectangular plates. Fig. 7. Individual with sarcode encysted, and throat of the shell closed by a thick laminar oper- culum, apparently composed of materials discharged from the sarcode. Shell composed chiefly of large oval plates, with smaller round ones and a few narrow rectangular ones. Fig. 8. Individual with the yellowish sarcode contracted into a ball and about to pass into the encysted condition ; with the food materials still retained. Shell composed of comparatively smaU round disks, largest in the neck, and mingled with a few spongilla spicules. Fig. 9. Empty shell, reversed position, composed mostly of large oval plates. Fig. 10. Individual with small sarcode forming a central ball. Shell composed of larger oval plates at the fundus, with scattered ones of the same kind in the throat, and the wide intervals occupied by small round plates. Figs. 11, 12. Two lateral views of small empty shells, accompanying the former specimen ; in one with mostly oval plates ; in the other with circular plates. Fig. 13, Broader lateral view of an empty shell, composed of linear plates mingled with a few scattered round and oval ones. Fig. 14. Broader lateral view of an empty shell, composed at the fundus mainly of large oval plates, and in the lower two-thirds of small round and oval plates, with scattered linear plates. Fig. 15. Empty shell, in outline, composed mainly of oval plates, decreasing in size towards the mouth, and mingled with smaller circular and a few rectangular plates. Fig. 16. SmaU shell, composed of comp.aratively very large oval plates, mingled with minute round ones. Fig. 17. Empty shell, composed of circular plates, split at the fundus, showing that the fissure follows the intervals of the plates. Fig. 18. Shell, of narrow rectangular and oval plates, from which a broad strip was broken away, showing that the fracture follows the intervals of the plates. Fig. 19. Fragment of the same shell more highly magnified. 850 diameters. Fig. 20. Similar fragment, in outline, from a different focus. PLATE :-:>:i! . Thos SircUii- ^ don Liili NEBELA COLLARIS. PLATE XXIII. Figs. 1-7.— NEBELA COLLAEIS. Narrower variety tlian tlie more common form, with a pair of minufe apertures rendered promi- nent at the narrower border of the shell, marked.d in fig. 4. Fig. 1. Broader lateral view, with protruded pseudopods. The shell composed of large oval plates. Sphagnum of Abseoom, N. J., September, 1874. 533 +. Fig. 2. Broader lateral view of an individual with encysted sarcode, and shell closed with a thicli laminar operculum, above which there is an accumulation of discharged excrementitious matters. Shell composed of intermingled linear and circular plates. Fig. 3. Outline of the narrower lateral view of the same. Sphagnum of Schooley's Mountain, New Jersey, October, 1874. 533 +. Figs. 4-6. Three views of the same individual: — fig. 4, broader lateral view; fig. 5, narrower lateral view ; the sarcode visible in both and with protruded pseudopods. Shell composed of circular plates decreasing in ^ize towards the mouth. Fig. 6. Outline of a transverse section. Sphagnum of Absecom, N. J. , May, 1876. 533 +. Fig. 7. Broader lateral view of an individual with reticulated shell and encysted sarcode ; the throat of the shell closed by a lenticular operculum; Absecom pond, New Jersey, October, 1875. 350 -}-. Figs. 8-19.— NEBELA FLABELLULUM. Fig. 8. Broader lateral view of a living individual in the normal position, with protruded pseudo- pods, and mth shell composed of nearly uniform, large oval plates. The large clearer central spot at the fundus of the sarcode indicates the nucleus ; and foui clear vesicles at the periphery contiguous to the latter indicate contractile vesicles. Breadth of shell, 0.097 mm. by 0.04 mm. Sphagnum of Abse- com, N. J., September, 1875. 700 diameters. Fig. 9. Broader lateral view of an individual, with protruded pseudopods. Shell composed of mostly circular plates of very variable size. Two contractile vesicles are seen, of which one occupies a prolongation of the sarcode at the fundus on the left. Fig. 10. Outline of a transverse section, with the mouth. Same locality. 500 diameters. Fig. 11. Broader lateral view of a living individual. Shell composed of circular plates, of which the larger ones are scattered with an approximation to regularity, while the smaller ones occupy the intervals. Sphagnum, Swarthmore, Delaware County, June, 1877. Figs. 12, 13. Two views of the same individual, with the sarcode contracted into a central ball. Shell composed of circular plates. The narrower side viewed in a different focus from the broader side. Absecom, N. J., October, 1874. Fig. 14. Broader lateral view of an individual, with the sarcode contracted into a ball, and con- taining a large and uniform granular nucleus. Shell composed of linear plates intermingled with round and oval plates ; and the mouth closed by an operculum. Longicomiug, N. J., October, 1875. Fig. 15. Broader lateral view of an individual in which the shell is not prolonged into a neck. Common form in sphagnum of Tobyhanna, Pokono Mountain, Pennsylvania, July, 1876. Fig. 16. Broader lateral view, reversed, of an empty shell composed of large mostly circular plates with the intervals occupied by small ones. Found in tho same locality. Fig. 17. Empty shell composed of oval plates. Absecom, N. J. Fig. 18. Empty shell, of circular and oval plates of variable size, mingled with linear pl.ates. With the preceding. Fig. 19. Empty shell of circular, oval, square, and linear plates. Egg llai-bor, N. J., May, 1877. US HEOLOGICAL SURVICY OF THE TERRITORIES PLATE yxm ■'on LsidvDel 1 7 NEBEI-.A COLLARIS 8 19 N FLABELLULUM. PLATE XXIV. Figs. 1-10.— NEBELA CAEINATA. Fig. 1. Broader Lateral view of a living individual, with protruded psondopods, and shell com- posed of thin plates of variable shapes. Fig. 2. Outline of the narrower side view. Fig. 3. Transverse section with outline of the mouth. Sphagnum of Absecom, N. J., June, 1877. 250 diameters. Fig. 4. Broader lateral view of an individual in which the saroode is of greater proportionate extent than in the preceding, and the shell composed of plates of varied shapes has also a few particles of jsand attached — a rare occurrence in any species of Kebela. Absecom, October, 1874. 350 +. ■/ Fig. 5. Individual with sarcode contracted into an oval hall, and throat of shell closed by a lami- nated operculum. The shell composed of thin angidar plates. Sphagnum, Swarthmore, Delaware County, Pennsylvania, June, 1877. 250 -)-. Breadth of shell, IM68 mm. by 0.04 mm. Fig. 6. View of one-half of the broader side of an empty shell, composed of round and oval plates of very unequal sizes. Absecom, N.J. Shell, 0.088 mm. by 0.036 mm. 500-(-. Fig. 7. More highly magnified view of a portion of the same under a different focus. Fig. 8. View of one-half of an empty shell with a comparatively narrow carina ; the shell com- posed of large oval plates, with small and mostly circular ones in the intervals. Absecom, N. J. 350 -|-. Fig. 9. View of one-half of the broader side of an empty shell with a wide or deep carina; the shell composed mostly of minute round plates, intermingled with linear plates and a few large oval ones. Absecom, N. J. 350 -f . Fig. 10. Empty shell, with broad keel, composed of chitinoid membrane incorporated with scat- tered particles of sand, etc. Absecom, N. J. 100 diameters. Fig^ 11, 12. -NEBELA COLLARIS. Fig. 11. Empty shell, composed of chitinoid membrane, incorporated with thin angular sUicious plates, separated by narrow intervals. Sphagnum, Vinelaud, N. J., September, 187G. 250 diameters. A similar specimen found on Bro.ad Mountain, Pennsylvania, mth shell 0.1 mm. long, .and 0.068 mm. by 0.02 mm. broad. Fig. 12. Empty shell composed of thin, irregular, angular silicions plates in close juxtaposition. 500 diameters. Breadth of shell 0.064 mm. by 0.02 mm. This and the preceding form are transitional to the compressed variety of Difflugia pyriformis. Fig. 13.— NEBELA HIPPOCREPIS. An empty shell, with inflected hoUow, spur-Uke processes ; the shell composed of circular over- lapping plates. Absecom pond, New Jersey, September, 1876. 250 diameters. Figs. 14-17.— NEBELA BAEBATA. 500 diameters. Fig. 14. Broader lateral view of an individual, the shell nearly replete with the sarcode and with projected pseudopods. The entire surface of the shell hirsute. Sphagnum water, Absecom, Septem- ber, 1875. Figs. 15, 16. Two views of an individual, with the sarcode withdrawn into the body of the shelL Same locality. Fig. 17. Individual with the sarcode contracted into a ball, and with the neck of the shell occu- jiied with discharged excrementitious matter. Same locality. Figs. 18, 19.— NEBELA. Fig. 18. An empty shell, the broader lateral view, reversed, composed of circul.ar plates of un- equal size. Intermediate in character to' Nehela barhata and Nehela collaris, being shaped like the former, but without oils as in the latter. Absecom, N. J., April, 1875. 500 -|-. Fig. 19. An empty shell nearly like the former. China Lake, Uinta Mountains, Wyoming Ter- ritory, August, 1877. 100 -f . Figs. 20-25.— QUADRULA SYMMETRICA. Fig. 20. Lateral view of a Uving individual. Around the base of the sarcode there were numerous detached plates like those of the shell. Pond at Vinelaud, N. J., September, 1876. 500 +. Figs. 21, 22. Two empty shells. Absecom pond, N. J. 500 -|-. Fig. 23. Empty shell. Ditch on the Schuylkill, above Manayunk, Philadelphia, April, 1877. Fig. 24. Plates of a similar shell highly magnified. FiG;25. Broader lateral view of an individual in which the sarcode is contracted into an oval discoid ball, and the mouth of the shell is closed with a thick laminated operculum. The plates of the shell arranged in a much more diagonal course thojx usual. Sphagnum, Absecom, N. J., October, 1874. 350 diameters. US r-K.n mGICAL SURVEY OF T HE TERRITORIES. PLATE XXTv^ ^"^ ] \ I \ '^ 3 .\>->^^-'-. r * cod ,;^ 23 i*^*^ 1 fy 1^- c^; ~7 i.\< 19 il-^35- Jtl TK^jK Smclftir »■ S^" 1 - 10 NEBELA CARJTSIATA 11-12 1^ COLEARIS. 13 N HIPPOCREFTS 18-13 l^EBELA, 20-25. QUADRULA SYMMETRICA. 14-17. N. B AREATA. PLATE XXV. Figs. 1-8.— NEBELA ANSATA. 250 diameters. Fig. 1. Broader lateral view of a well fed, active individual, with Barcode nearly filling tlie shell, extending into (he appendages, and with projected pseudopods. The ahundance of food conceals the nucleus ; a contractile vesicle seen on each side. The large vacuole within the neck was ohserved gradually to approach the mouth of the shell and discharge its contents. Sphagnum, Absecom, N. J., June, 1877. Fig. 2. Individual with smaller sarcode attached to the fundus of the shell by tapering threads, and with projected pseudopods. Nucleus visible as a clearer spot ; and a contractile vesicle on each side. Sarcode in the act of discharging excrementitions mat ier. Same locality, September, 1875. Fig. 3. Individual in w hich the abundant sarcode is withdrawn from the mouth of the shell The yellow balls apparently food. With the preceding. Fig. 4. Individual in which the sarcode is contracted into an oval discoid ball, ready to become encysted ; the mouth of the shell closed by a laminated operculum composed of materials discharged from the sarcode. Fig. 5. Outline of the narrower lateral view of the same. Absecom, N. J., September, 1874. FiGS.6, 7, 8. Views from three specimens exhibiting the different forms of elements composing the shell. Same locality. Figs. 9-14.— NEBELA HIPPOCEEPIS. From sphagnum of Absecom, N. J. 250 diameters. Fias. 9-11, 13. Three views of the same individual : — tig. 9, broader lateral view, with sarcode extended and pseudopods projected; flg. 10, narrower lateral view of the same; fig. 11, broader lateral view, with the sarcode retracted from the mouth of the shell ; tig. 13, superior view as the animal, presents itself beneath the microscope when in the normal position. August, 1874. Figs. 12, 14. Two views of an individual, with the sarcode very small, apparently exemplifying a starved condition. In Hg. 12 the sarcode is greatly extended atid attached to the fundus by long pseudopodal tapering threads. Pseudopods are protruded, and the sarcode is in the act of discharging excrement. In fig. 14 the sarcode is retracted and has formed an attachment to the ends of the horse- shoe appendage. September, 1874. U.S. GEOLOGICAL SURVEY OF THE TERRITORIES. PLATE XXV -^»=^J¥=-^ 1-8 NEBELA ANSATA.9~14 NEBELA HIPPClCPcEPLS PLATE XXVI. Figs. 1-11.— HELEOPEEA PICTA. From the sphagnum of sphiignous swamps of New Jersey. 500 diameters. Fig. 1. Broader lateral view of an individual, with a profusion of pseudopods. April, 1875. Fig. 2. Broader lateral view of an individual, with the sarcode forming an encysted ball, and with the shell closed by a lenticular, laminated operculum. April, 1877. Pig. 3. Narrower lateral view of an empty shell. Fig. 4. Individual with the sarcode encysted, and with the mouth of the shell closed by an oper- culum. April, 1877. Fig. 5. Another specimen in the same condition as the preceding, June, 1877. Figs. 6, 7. Two views of the same individual, with encysted sarcode, and mouth of the shell closed. The fundus of the shell with an accumulation of Incorporated grains of sand. October, 1874. Figs. 8, 9. Two views of the same specimen. In flg. 8 numerous isoLated green corpuscles are seen, supposed to be germs derived from the breaking up of the sarcode. In fig. 9 the mouth is seen to be contracted. Collected in September, 1874, and observed December 30, of the same year. Fig. 10. Specimen containing scattered green corpuscles or germs. Fundus of the shell with incorporated sand grains. November, l'i74. Fig. 11. Transverse view of o,n empty shell showing the mouth. Figs. l:i-20.— HELEOPEEA PETEICOLA. -Fig. 12. Broader lateral view of an active individual, with 'projected pseudopods; the fundus of the shell loaded with an accumulation of large grains of sand. Hoaumonton pond, New Jersey, Septem- ber, 1877. 333 diameters. Fig. 13. Broader lateral view of an individual with encysted sarcode, and with the mouth of the shell closed by an operculum. Fig. 14. Narrower lateral view of the same, in outline. Sphagnum, Longacoming, N. J., September, 1875. 500 diameters. Fig. 15. Empty shell, with conical fundus; broader lateral view. Absecom, N. J., September, 1875. 250 +. Figs. 16, 17. Two views of an empty shell. Absecom pond, N. J. 200 +. Fig. 18. Broader lateral view of an empty shell. Fig. 19. Transverse section of the same, with the mouth. Sphagnum, Absecom, N. J. 200 -{-. Fig. 20. Emxity shell thickly incorporated with fragments of diatoms and saud. Absecom pond, N. J. 250 +. Figs. 21-24.— NEBELA CAUDATA. Sphagnum of Absecom, N. J. 500 diameters. Fig. 21. Broader lateral view of an empty shell. June, 1877. Fig. 23. Individual in which the shell appeared to be composed of chitinoid membranej with cir- cular disks. The sarcode encysted, and the mouth of the shell closed by a thick laminated operculum. September, 1874. Figs. 23, 24. Two views of the same individual, with encysted sarcode, and mouth of the shell closed. The shell was of chitinoid membrane of obscure structure. April, 1876. U S. GEOLOGICAL SURVEY OF THE TERE^ITORIES ATE XXVT . 1-lLHELEOPER.A PICTA. 12-80 H PET,R1C OLA Rl -ff4-. NEBELA CAUDATA 1 PLATE XXVII. AECELLA VULGARIS. In most of the figures of Arcella in this and the succeeding plates the cancellated or dotted appear- ance of the shell is omitted. The color is less varied than in the originals. Figs. 1, 2. Lateral and inferior views of the same individual, with extended pseudopods. Bog on the Schuyltill, West Philadelphia, June, 1877. 250 +. Fig. 3. Lateral view of an empty shell. Ditch below Philadelphia. 250 -f-. Fig. 4. Lateral view of a colorless, transparent individual, with projected pseudopods, and Bar- code attached to the interior of the shell by tapering threads. Swarthmore brick-pond, Delaware County, Pa., September, 1874. 500 +. Fig. 5. Individual with colored shell, the sarcode visible within. Same locality, and magnified same degree. Fig. 6. SheU. of a small individual. Original was living, and the shell of a brown color. Fort Bridger, Wyoming Territory, August, 1877. 250 -(-. Fig. 7. Lateral view of an active individual, with sarcode visible, with protruded pseudopods, and with pale yellow shell. Absecom pond. If. J., April, 1876. 350 +. Fig. 8. Upper view of a colorless individual. The sarcode attached by tapering threads to the interior of the shell ; around its border five contractile vesicles visible, and more internally a pair of nuclei opposite each other. The dotted appearance of the shell represents the cancellated structure. a, one of the nuclei. Fairmount Park, Philadelphia, June, 1878. 250 +. Figs. 9, 10. Two views of the shell from a living specimen ; inferior view ehowing a crenulated mouth, and lateral view showing the inflection of the base to the mouth. Absecom pond, Kew Jersey, August, 1876. 350 +. Figs. 11, 12. Lateral and upper views of au individual, with the sarcode visible, and with pro- jected pseudopods. a, nuclei; h, contractile vesicle; c, amoeboid corijuscles in the interval between the sarcode and the shell ; d, large air-bubble. Fairmount Park, June, 1877. 250 -)-. Fig. 13. Inferiorviewof a similar specimen. Ditch below Philadelphia, September, 1877. 250 -|-. Figs. 14, 15. Inferior and lateral views of the same individual. In the former view the sarcode appears of irregular form, and it exhibits a single nucleus and three contractile vesicles. Absecom pond. New Jersey, June, 1877. 250 -|-. • Fig. 16. Small shell (of a dark ochreoue color) with pitted surface. Woodstown pond. New Jer- sej', September, 1877. 250 -|-. Fig. 17. Side view of a pair of individuals in conjugation, both of the same size ; the shell of one diirker than the other. Sw.arthmore brick-pond, September, 1874. 250 -f. Fig. 18. Inferior view of a specimen, living and active, in which portions of the shell appear as if bitten out. Atco,N. J., June, 1877. 250 -1-. Figs. 19, 20. Inferior and lateral views of ait individual, with constricted shell. Fairmount Park, Philadelphia, May, 1878. 250 +. Figs. 21, 22. Upper \iews of two minute specimeus, probably young individuals, with the sarcode showing a single nucleus and several large contractile vesicles. Atco, N. J., October, 1877. 1,000 +. Fig. 23. Lateral view of a living specimen, with pitted shell. China Lake, Uinta Mountains, Wyoming Territory, August, 1877. 500 -f. Fig. 24. Two similar individuals in conjugation, with the shells of different shades of color. With the preceding. Figs. 25, 26. Inferior anji lateral views of an individual, with pitted shell. Swarthmore, Delaware County, Pa., April, 1874. 350 +. !Figs. 27, 28: Superior and laterul views of an empty shell, with irregulaily pitted surface. Same locality. Figs. 29, 30. Lateral aud inferior views of an individual, with pitted shell. Ditch below Phila- delphia, June, 1876. 350 -|-. Fig. 31. Lateral view of a^specimen. Fort Bridgpr, Wyoming Territory, August, 1877. 250 +. Figs. 32, 33. Lateral aud inferior views of a specimen, with the sarcode encysted, and surrounded with flocculent matter, probably excrembutitious. Atco, N. J. , June, 1877. 5t0 -|-. Fig. 34. Upper view of an empty colorless shell. Smarthmore brick-pond, September, 1874. 350 + Fig. 35. Cancellated structure of the shell of Arcella highly magnified. 113 GEOLOGICAL SURVEY OF' TflF: TFv RRITORIE.S. PLATE XXVfl. '^-^aLpidy.Dei iim^lajr* 3or..Lilli ARCELLA VULGARIS PLATE XXVIII. Figs. 1-7.— AECELLA VULGARIS. Pig. 1. Lateral view of a pair in conjugation, in one of wHcli the shell is colorless. The mssaes of sarcode as ohserved were not in nnion. Egg Harbor, N. J., September, 1877. 500 diameters. Fig. 2. Lateral view of an empty shell, with an even dome. Absecom, N. J. 500 diameters. Fig. 3. Lateral view of a specimen, with the sarcode forming a large encysted ball, and causing the eversion of the usual funnel-like base of the shell. Same locality, March, 1876. 350 -)-. Figs. 4, 5. Inferior* and lateral views of an empty shell, with depressed fundus. Found with the preceding. 350 -f. Figs. 6, 7. Superior and lateral views of a shell of quadrate outline, and depressed fundus. Pond on Pokono Mountain, Pennsylvania, July, 1876. 250 +. Figs. 8-13.— AECELLA VULGAEIS, var. angulosa. Figs. 8, 9. Superior and lateral views of the same specimen, the former represented without the sarcode. Woodstown pond, New Jersey, September, 1877. 250 +. Figs. 10, 11. Superior and lateral views of a similar specimen, found with the preceding. The sarcode not represented Figs. 12, 13. Superior and lateral views of another, and similar specimen foimd with the pre- ceding. I Figs. 14-38.— AECELLA DISCOIDES. Figs. 14, 15. Inferior and lateral views of an individual. In the sarcode of the former a p.aii of opposite nuclei and several contractile vesicles visible. Swaithmore brick-pond, Delaware County, Pa., September, 1874. 350-)-. Figs. 16, 17. Inferior and lateral views of aiiother individual found with the former. Fig. 18. Lateral view of a shell. China Lake, Uinta Mountains, Wyoming Territory.- 250 -(-. Figs. 19-21. Lateral views of three shells from living specimens. Woodstown pond. New Jersey, September, 1877. Fig. 19 is inadvertently unsymmetrical, and should be the same on the right as on the left. Jk?^ Fig. 22. Lateral view of a large Ifl^^Wltial, with extended pseudopods. As exemplified iu this figure, while the mass of sarcode within xhe shell and the pseudopods exterior to the base are visible, the intermediate portions extending through the funnel, from their transparency, cannot be seen. Fort Bridger, Wyoming Territory, August, 1877. 250 -j-. Fig. 23. Inferior view of a nearly colorless individual. Tha sarcode exhibits a pair of opposite nuclei and seven conspicuous contractile vesicles. Absecom pond, N. J., April, 1875. 350 -|-. The height of the shell was about one-third the breadth. Fig. 24. Inferior view of an individual, "with projected pseudopods. The sarcode exhibts a pair of nuclei, four contractile vesicles, and on the right upper border a large air-bubble. Fig. 25. Lateral view of the shell of the same. Bristol Canal, Pennsylvania, September, 1876. 500 -\-. Figs. 26, 27. Inferior and lateral views from the same individual. In the interior sarcode of the former the two opposite nuclei are seen, and at the border five contractile vesicles. Pond on Darby Creek, Delaware County, Pennsylvania, April, 1876. 500 -f. Fig. 28. Inferior view of a large individual (correct outline, though not quite regularly circular). Three nuclei visible in the sarcode ; and a number of contractile vesicles at the border. On Utriculnria, from Jacksonville, Florida, May, 1875. 266 +. Fig. 29. Inferior view of .a colorless individual, acted on by an ammoniacal solution of canuino ; the nuclei as they appeared stained deep red. Absecom pond. Now Jersey, June, 1874. 350 -)-. Figs. 30, 31. Two views of the same individual. Tlio shell pale yellowish, very thin and ilexible. China Lake, Uinta Mountains, Wyoming Territory, August, 1877. .'lOO -|-. Fig. 32. Inferior view of an empty shell with quadrately rounded outline and oval mouth. Jacksonville, Fla. 250 +. * ' Fig. 33. Lateral view of a specimen, having the same shape as the former in the inferior view. Found with the preceding. Fig. 34. Inferior view of a specimen with oval outline. With the preceding. Figs. 35, 36. Inferior and lateral views of a specimen; the former with oval outliue, and oval mouth whose long diameter crosses that of the shell. (The lithographer has inadvertently colored the two figures differently.) Found with the preceding. Fig. 37. Inferior view of a shell with oval outline and mouth. Absecom pond, New Jersey. Fig. 38. Inferior view of shell, with trilobate outline and oval mouth. With the preceding. *Iii the empty shells, when tronsparent, the iurerior and superior views appear the same. U.S. GEOLOGICAL SURVEY OF THE TERRITORIES. PLATE XXVTTI 'JosLeidy.Del 3 Sir.clair A Son. LitK 1 - 7 ARCELLA VUI .GARIS 6-13.A ANGULOSA. 14-38 A DLSCOIDES. PLATE XXIX. AECELLA MITEATA. Figs. 1, 3. Inferior and lateral views from the same individual. In the former figure the central undulating circle is the mouth ; and the second circle is produced by the border of the base of the shell. In the latter figure, the body of the sarcode is seen attached to the mouth of the shell by a long neck, and the periphery, by means of numerous threads, to the inside of the shell. China Lake, Uinta Mountains, Wyoming Territory, August, 1877. 250 diameters. Figs. 3, 4. Inferior and lateral views from an individual similar to the former. Atco, N. J., Sep- tember, 1877. 250 -f . An abundant form. Figs. 5, 6. Inferior and lateral views of an individual. Absecom pond. New Jersey, September, 1874. 350 +. The dotted appearance of the shell in fig. 6 represents the cancellated structure. Figs. 7, 8. Inferior and lateral views of an individual in which the sarcode is retracted into the fundus of the shell. The sarcode contained a single nucleus. Atco, N. J., September, 1877. 250 -|-. Figs. 9, 10. Lateral and inferior views of a specimen, in which the shell has a pyramidal summit, perpendicular sides, and a heptagonal base. Absecom pond, New Jersey, October, 1877. 250 -1-. Fig. 11. Lateral view of a specimen, exhibiting the sarcode and its attachments, and projected pseudopods. Same locality, May, 1877. 500 -[-. Fig. 12. Lateral view of an empty shell, with even, dome-like fundus. Absecom pond, N. J., Sep- tember, 1875. 250 -f. Fig. 13. Lateral view of a colorless individual, exhibiting the sarcode and its connections. Atco, N. J. , September, 1877. 250 -f. Fig. 14. Lateral view of an individual. Absecom, N. J., September, 1875. 250 +. Fig. 15. Lateral view, with visible sarcode. Tobyhanna, Pokono Mountain, Pennsylvania, July, 1876. 250 -f. Fig. 16. Lateral view of a large individual, with shell having depressed sides and pyramidal dome. Atco, N. J., September, 1877. 250 +. Fig. 17. Lateral view of an individual with perfectly colorless shell ; with the sarcode and its attachments distinctly visible, and with protruded pseudopods. The dotted appeoiance on part of the shell represents the cancellated structure in focus. Absecom pond, N. J., August, 1874. 250 -f . Fig. 18. Lateral view of a specimen, with visible sarcode and protruded pseudopods. Absecom, N. J., September, 1874. 350 +. Figs. 19, 20. Inferior and lateral views from an individual. With the preceding. 350 -|-. Figs. 21, 22. Inferior and lateral views from an individual, in which the sarcode was contracted into a spherical ball lying on one side of the cavity of the shell. Found with the preceding. Fig. 23. Lateral view of a pyriform specimen. With the preceding. 350 -j— Fig. 24. Lateral view from a specimen, in which the sarcode contained a multitude of chlorophyl grains. Absecom, N. J., July, 1876. 250 +. c', mOLOGlCAL SURVEY OF THE TERF'ITORIF.S PLATE XXIX ■ic-3-LeidLy.Del ARCELLA MITRATA PLATE XXX. Figs. 1-a.— AECELLA AETOCEEA. 2&0 diameters. Figs. 1, 2. Inferior and lateral views ; the former exhibiting the interior sarcode with its abun- dance of ohlorophyl grains. Absecom pond, New Jersey, September, 1874. Figs. 3, 4. Inferior and lateral views of a shell. Sphagnum of Absecom, N. J., April, 1876. Figs. 5, 6. Inferior and lateral views of a shell ; in the former with irregularly oval outline. Found with the preceding. Figs. 7, 8. Inferior and lateral views of an individual, with the sarcode in an encysted condition. Shell with an irregularly oval outline as seen in the former view. The ball of sarcode produced an eversion of the base of the shell as seen in the lateral view. In the interval of the sarcode and shell a number of amoeboid corpuscles were visible. With the preceding. Fig. 9. Lateral view of a large empty shell. Absecom pond, N. J., September, 1874. Figs. 10-19.— AECELLA DENTATA. 250 diameters. I Figs. 10, 11. Inferior and lateral views of an empty shell. Ditch below Philadelphia. Figs. 12, 13. Inferior and lateral views of a shell. Fairmount, Philadelphia. Figs. 14, 15. Upper and lateral views of a shell. Budd's Lake, New Jersey, October, 1874. Figs. 16, 17. Inferior and lateral views of a shell. Ditch below Philadelphia. Fig. 18. Lateral view of a shell. Budd's Lake, New Jersey. Fig. 19. Inferior view of a living individual. The sarcode exhibits a pair of opposite nuclei, several contractile vesicles, and a projected pseudopod. Found with the preceding, u, nucleus; 6, contractile vesicle. Figs. 20-34.— CENTEOPYXIS ECOEIUS = the spineless variety of CENTEOPYXIS ACULEATA. The shell in most examples composed of sand grains, cemented in close juxtaposition. 200 diameters. Fig. 20. Inferior view of a living individual, with protruded pseudopods. The shell with large sinuous mouth ; the height about one-third the breadth. Ditch below Philadelphia, September, 1875. Figs. 21,22. — Inferior and lateral views of an empty shell. Swarthmore brick-pond, Delaware County, Pa. Figs. 23, 24. Inferior and lateral views of an empty shell, with a large circulai- mouth. Fairmount Park, Philadelphia. Fig. 25. Inferior view of a shell, with a small circular mouth. Ditch below Philadelphia. Fig. 26. Inferior view of a shell, with trilobed mouth. Pond on Darby Creek, Delaware County, Pennsylvania. Fig. 27. Inferior view of a shell, with quadrilobed mouth. Same locality. Figs. 28, 29. Inferior and lateral views of a shell, with quadrilobate mouth. China Lalce, Uinta Mountains, Wyoming. Figs. 30, 31. Inferior and lateral views of a living individual, with extended pseudopods. The brown shell, composed of sand grains, with the cement of a darker hue of the same color. Ditch below Philadelphia, June, 1874. Fig. 32. Inferior view of a living individual, with extended pseudopods. The shell composed of chitinoid membrane incorporated with dirt and sand. Pond on Darby Creek, Delaware County, Pa., October, 1874. Figs. 33, 34. Inferior and lateral views of an empty shell, composed of sand. Same locality as the preceding. U.S.GFOI.OGICAL SURVFIY 01-' t;iK TERRITORIES. ATE XXX 1-9. ARCELLA ARTOCREA . 10-19. /J^CELLA DENTATA 2 O - 34 CElITROPVTvriS ECORNIS PLATE XXXI. CENTROPYXIS ACULEATA. Fig. 1. Inferior view of a living specimen, with pseiidopods protruded ; shell composed of chiti- noid memhrane, with scattered sand grains, and coarser ones loaded along the fundus. 200 diameters. Spencer pond, Maine, September, 1877. Fig. 2. Inferior view of a living individual, with shell of chitinoid membrane and incorporated grains of sand. 200 diameters. Among Chara, in pond on Bushkill Creek, Easton, Pa., June, 1676. Fig. 3. Inferior view of a shell composed of brown chitinoid membrane, with incorporated rods and irregular angular plates. 200 diameters. Ditch below Philadelphia. Figs. 4, 5. Inferior and inferior oblique views of the same .specimen. Shell of chitinoid membrane with scattered sand grains. 200 diameters. Found with the preceding. Figs. 6, 7. Biferior and lateral views of a sj)ecimen. Shell of brown chitinoid membrane, finely punctate, and with scattered sand and diatoms. On Utricularia, from Jacksonville, Fla. Fig. 8. Inferior view of a shell of brown chitinoid membrane, with incorporated sand along the posterior border. 250 diameters. Sphagnum of Absecom, N. J. . FSGS. 9, 10. Inferior and lateral views of a shell of chitinoid membrane, with a few incorporated diatoms and sand grains. 250 diameters. Absecom polid, New Jersey. Fig. 11. Lateral outline of the shell of a living specimen, composed of chitinoid membrane with sand grains, and with a single spine to the fundus. 250 diameters. Pond on Darby Creek, Pennsylvania. Figs. 12, 13. Inferior and lateral views. Shell composed of chitinoid membrane, with scattered grains of sand. 200 +. Sphagnuin of Absecom, N. J. Fig. 14. Inferior view of an empty shell of brown chitinoid membrane, entirely devoid of foreign matter, and finely and regularly punctate ; but the punctse not resolvable into cancelli as in the shell of Arcella. Ditch below Philadelphia, with Lemna and WoMSa. Figs. 15, 16. Inferior and lateral views. 250 +. Absecom, N. J. Fig. 17. Inferior view of a shell, composed of sand. 200 -f-. Ditches below Philadelphia. Figs. 18, 19. Inferior views of two similar specimens. Pond on the Delaware River above Easton, Pa. Figs. 20, 21. Inferior and lateral views of a specimen, composed of sand united by brown cement. Fort Bridger, Wyoming Territory. Fig. 22. Inferior view of a specimen composed of sand. Same locality. Figs. 23, 24. Inferior and lateral views of a specimen composed of sand. Partridge Island, Nova Scotia. Figs. 25, 26. Inferior and lateral views of a small specimen. 500 +. Dripping rocks of Fairmount Reservoir, Philadelphia. Figs. 27, 28. Inferior and lateral views of a shell, composed of chitinoid membrane with sand and dirt. 200 +. Atco,N.J. Figs. 29, 30. Inferior and lateral views. 350 +. Pond on Darby Creek, Pennsylvania. Fig. 31. Inferior view of a shcU, except the spines composed of diatoms. 350 +. Pokono Mount- ain, Pennsylvania. Fig. 32. Inferior view of a shell, composed of diatoms and sand. 500 -j-. Lake Hattacawanna, New Jersey. Figs. 33, 34. Inferior and lateral views of a shell of similar composition, pertaining to the variety Centropyxis ecornia. 500 -f . Abundant form with the preceding. Fig. 35. Lateral view of a shell, with spines fore and aft. 200 +. Ditch below Philadelphia. U.S. GEOLOGICAL SURVEY OF THE TFRRITORIES. PLATE XXXL ■JasLaidv, E Tnoa Sui.:lajr i Son Litli CENTROP'iXIS ACULEATA. PLATE XXXII. Figs. 1-25.— COCHLIOPODIUM BILIMBOSUM. The dotted appearance in the broad band or zone, and in the double contour line, in most of the figures, is intended to represent the finely cancellated structure of the investing membrane or shell, but is represented more distinct than natural. Fig. 1. Upper view of an individual, the broad dotted zone representing the expanded base or mouth of the shell. The nucleus seen centrally. 1,000 diameters. China Lake, Uinta Mountains, August, 1877. Fig. 2. Individual with the basal border of the shell expanded on one side — in the direction ot movement of the animal. With the preceding. 1,000+. Fig. 3. Upper view of an individual, with the basal border extended nearly all around. Among algsB, in ditches below Philadelphia, May, 1875. 1,000 +. Fig. 4. Individual with pseudopodal extensions opposite the extension of the basal border of the shell, and in the act of discharging excrementitious matter. 500 +. Among water-cress, in a spring on Darby Creek, Delaware County, Pennsylvania, April, 1875. Fig. 5. Lateral view of an individual, with psoudopods extending from beneath the expanded basal hand of the shell. 1,000 +. Ditch below Philadelphia, April, 1876. Fig. 6. Lateral view of an individual, with extended pseudopods, but with the basal band of the shell contracted. 500 +. Found with fig. 4. Fig. 7. Lateral view of an individual, with extended pseudopods, and extension of the basal band of the shell. With the preceding. 500 -|-. Fig. 8. Lateralview, with pseudopods, and with the basal band of the shell contracted. 500 +. Fort Bridger, Wyoming, August, 1877. Figs. 9, 10. Lateral and upper views of an individual. 500 -f . Spring on Darby Creek, Delaware County, Pennsylvania, April, 1875. Fig. 11. Lateral view, with the basal band of the shell drawn into folds. Same locality. Fig. 12. Upper view, with extension of the basal band on one side and a pseudopodal extension on the opposite side. With the preceding. Fig. 13. Upper view, with inflection of the basal band, and projection of pseudopods. With the preceding. Figs. 14-17. Four successive views of the same individual seen from above. Fig. 14, with in- flected basal band ; fig. 15, the band extended on one side ; figs. 16, 17, the band widely expanded all round. In all, pseudopodal extensions are seen, but their appearance across the basal band is drawn too darkly. Same locality as the preceding. Figs. 18, 19. Two views of an individual ; in the former as it appeared either spread upon or attempting to swallow a large diatom; in the latter, as it disengaged itself from the diatom, moving oflf in the direction of the expanded basal band. With the preceding. Fig. 20. Lateral view of a small individual, with inflected basal border, and with projected pseudo- pods. Among algsB at foot of fountain in front of City HaU, Market street, Philadelphia, August, 1878. Figs. 21, 22. Two views of an individual, with broad basal baud, in which the pvmctated appear- ance could not be detected. With the preceding. Fig. 23. Small individual, seen from above, with widely expanded basal band, in which no trace of the cancellated structure could be detected. S warthmore, Delaware County, Peimsylvania, May, 1875. Fig. 24. Lateral view of a specimen acted on by ammoniaoal solution of cannine ; the nucleus deeply stained. Fig. 25. Lateral view of a specimen acted on by a feeble solution of iodine in potassium iodide. Figs. 26-28.— COCHLIOPODIUM VESTITUM. 500 +. Fig. 26. Lateral view of an individual, with the basal band of the shell thrown into angular folds, and with the interior sarcode containing a large quantity of ohlorophyl granules. Absecom pond. New Jersey, May, 1865. Fig. 27. Lateral view of a colorless specimen. Same locality, September, 1874. Fig. 28. Lateral view of an individual, with yellowish shell, and with extended pseudopods. Uinta Mountains, Wyoming, August, 1877. Figs. 29-37.— CENTEOPYXIS ACULEATA. Figs. 29, 30. Lateral and inferior views of au empty shell, composed of chitinoid membrane. 500 +, Tobyhanna, Pokono Mountain, Pennsylvania. Fig. 31. Lateral view of an empty shell of chitinoid membrane. 500+. Spliiigimm, Absecom, N. J. Figs. 32, 33. Oblique lateral and inferior views of an empty shell. 250 +. Same locality as preceding. Fig. 34. Inferior view of a shell composed of chitinoid membrane, with incorporated diatoms. Empty and deeply stained brown. 350 +. Ditch below Philadelphia. Figs. 35, 36. Inferior and lateral views of a spineless shell, pert.aining to the variety CeniropyxU ecomis. The shell composed of chitinoid membrane incorporated with large sand grains. 250 +. Sphagnum, Absecom, N. J. Fig. 37. Inferior view of a shell, composed of chitinoid membrane with sand. 250 +. Swarth- more brick-pond, Delaware County, Pennsylvania. S. GEOLOGICA L SURVEY OF TflE TERRITORIES. PLATE X: .y .,y •■'^iM-,'^^ r ,t'f-^'^^ % .^-^'X 'j '9 i i "v'o \^ ^ ^M\ f M'^- t ^; 'V¥'«! '^■i' *•€"*' 4 ^l 1 ■loa Leidy Tp) ■i-..r *. 5<.T., L.tK PLACOCISTA SPINOSA ^ PLATE XXXIX. TRINEMA ACINUS. 500 rtiamctors, except -where specially indicated. Figs. 1-5. Large individuals, from sphagnum of Absecom, N. J. Fig. 1. luferior view* of au empty shell, exhibiting the mouth at lower part of the figure, and the circular plates with beaded margins. Fig. 2. Lateral view of the same specimen. Fig. 3. Inferior view of a second specimen. Fig. 4. Inferior lateral view of another specimen. Fig. 5. Inferior view of a living specimen. The pseudopods are extended ; and the sarcode exhibits the nucleus, several contractile vesicles, together with a quantity of yellowish food material. April, 1875. Figs. 6,7. Two views, inferior, of the same individual, showing successive changes in extension of the sarcode. Fairmount, Philadelphia. Fig. 8. Inferior view of a living specimen ; the sarcode exhibiting the nucleus, three contractile vesicles, and a single forked pseudopod. Pokono Mountain, Pennsylvania, July, 1876. Fig. 9. Inferior view of a living specimen. Sphagnum, Broad Mountain, Pennsylvania, Septem- ber, 1876. Figs. 10, 11, Inferior and lateral views of an empty shell. With moss in crevices of the pave- ments of Philadelphia. Figs. 12, 13. Inferior and lateral views of a living specimen. From moss and lichens in the crotch of an apple-tree. Swarthmore, Delaware County, Pennsylvania, December, 1877. 066 diameters. Figs. 14, 15. Inferior and lateral views of an empty shoU. Sphagnum, Bro.ad Mountain, Penn- sylvania. Figs. 16, 17. luferior and lateral views of a living specimen. Swamp near Bristol, Pa., Septem- ber, 1876. Fig. 18. Inferior view of a living individual. Uinta Mountains, Wyoming, July, 1876. Figs. 19, 20. Lateral and inferior views of an empty shell. Sphagnum of Egg Harbor, N. J. 666 diameters. Fig. 21. Inferior view of a living specimen. Uinta Mountains, Wyoming, Jaly, 1876. Figs. 22, 23. Lateral and inferior views of a living individual. Found together with Euglypha and Eotifers, among moss, in the yard of my house, Philadelphia, August, 1878. 1,000 diameters. Fig. 24. Inferior view of a minute living individual. Sphagnum of Mount Vernon, Ala., Octo- ber, 1875. Fig. 25. Apparent production or birth of an individual from its parent. The upper is the parent ; the lower the offspriirg. Sphagnum of Pokono Mountain, Pennsylv.ania, July, 1876. Fig. 26. Lateral view of a sijecimen, in which the sarcode is encysted. Yard of my house, Phila- delphia, June, 1874. Fig. 27. Lateral view of a similar specimen, from sphagnum of Absecom, N. J., October, 1875. Figs. 28, 29. luferior and lateral views of a shell. Ditches below Philadelphia. Fig. 30. Inferior view of an empty shell. Broad Mountain, Pennsylvania. Fig. 31. Inferior view. Darby pond, Pennsylvania. Figs. 32, 33. Inferior and lateral views. Mount Vernon, Ala. Figs. 34, 35. Inferior and lateral views. Fort Bridger, Wyoming Territory. Figs. 36, 37. Lateral views of two specimens. Fort Bridger, Wyoming. Fig. 38. Minute specimen, inferior view. Mount Vernon, Ala. Fig. 39. Inferior view. Uinta Mountains, Wyoming. Figs. 40-42. Inferior views of three shells. Mount Vernon, Ala. Fig. 43. Lateral view of a minute shell. Uinta Mountains, Wyoming. Fig. 44. Inferior view of a living specimen. Sphagnum, Swartlunorc, Delaware County, Penn- sylvania, September, 1874. Fig. 45. Inferior view of a shell. Spring near Darby, Delaware County, Peunsylvauia. Fig. 46. Inferior view of a shell. Mount Vernon, Ala. Figs. 47, 48. luferior and lateral views. Jacksonville, Fla. Figs. 49, 50. Inferior and lateral views. Sphagnum, Mount Vernon, Ala. Figs. 51, 52. Inferior and lateral views. Sphagnum, Mount Vernon, Ala. Figs. 53, 54. Inferior and lateral views. Jacksonville, Fla. Figs. 55, 56. Inferior views of two specimens. Fort Bridger, Wyoming. Figs. 57, 58. Inferior and lateral views. Mouth of a cave on Bushkill Creek, near Easton, Pa. Fig. 59. Inferior view. Mount Vernon, Ala. FfG. 60. Lateral view. Uinta Mountains, Wyoming. Fiqs. 61, 62. Inferior and lateral views. Jacksonville, Fla. Fiq; 63. Inferior view. Mount Vernon, Ala. FiGf. 64. Inferorlateral view, with sarcode resolved into spores. Sphagnum, Absecom, N. J., Octo- ber, 1875. Fig. 65. Inferipr view. Mouth of cave, Bushkill Creek, Easton, Pa. Fig. 66. Lateral view, Swartl^more, Pa. Figs. 67, 68. Inferior and lateral vjevrs. Jacksonville, Fla. * The inferior views as they usually appear, tilted forward, or lying in the field of the miorosoope on (ieir anterior face. From the transparency of the specimens they appenr the ^apie when yiewed from behind or in front. U,ST.EOLOGICAL SURVEY OF THE TERRITOPIES. PLATE XXYAY. 1 'Jos Leidv. Pel T>,as Sinclair S. Son, l-.th TRIMEMA ENCHEE/S 1 PLATE XL ACTINOPHEYS SOL. Fig. 1. An ludividual feeding on green zoospores of an alga. Ditches bolow PMladelpMa, among Lemna, Wolffia, etc. May, 1874. 500 diameters. Figs. 2-4. Three views of the same individual, exhibiting the successive steps in the capture and swallowing of a Euglenia. In flg. 3 the rays are left out, and in fig. 4 only partially given. Fair- mount Park, June, 1874. 500 diailieters. Fig. 5. Heliozoon, supposed to be an A. sol. The nucleus distinctly visible ; large vacuoles at the periphery; and only about half a dozen rays. Fort Bridger, Wyoming, July, 1877. Fig. 6. Individual of uniform granular constitution, without vacuoles, and exhibiting a contrac- tile vesicle at the boundary. Found with the preceding. Fig. 7. An individual, with even periphery, exhibiting .a central nucleus, numerous vacuoles, and a large colored food-ball. Besides the ordinary filamentous rays, it projected digitate pseudopodal pro- cesses of protoplasm. Fig. 8. Another individual apparently ready to undergo division. It contains a number of colored food-balls. With the preceding. Fort Bridger, Wyoming, August, 1877. 500 diameters. Fig. 9. Large individual, of finely granular constitution, with visible central nucleus, and large peripheral vacuoles (the Latter iijadvertently left unshaded). Bristol Canal, Pennsylvania, with Cerato- phyllum. August, 1876. 500 diameters. Fig. lOr A pair in conjugation. The contractile vesicles seen above, a, discharge of an effete ball. Swarthmbre bricK-pond, Delaware County, Pennsylvania, May, 1875. 500 diameters. Figs. 11-22. A pair of individuals, exhibiting the successive changes in division. Some of the flgnres are given merely in outline, and in a number the rays are not drawn. 350 diameters. Fig. 11. The pair as first noticed, with a large gr.anular baU between them ; fig. 12, as seen three hours subsequently ; fig. 13, two hours later ; figs. 14-16, successive changes during the next hour, when separation occurred as in fig. 17. Figs. 18, 19, successive changes of the left-hand individual leading to separation into a pair. Figs. 20-22, successive changes of the right-hand individual leading to separation. us GEO LOGICAL SURVEY OF THE TERRITORIES. PLATE XL, i 2: :Mf .4^ A- 't>,'..».vl'^ vl'^ ''"^. w ''^■■:it^MUi/^-> m w¥^ ''^^m^r.^X V-— ** ^ ■<■■■ \ \ \ ■■ ' ■ i^f ■'os-Leidy, P PLATE XLI. ACTINOSPH^EIUM EICHHORNII. Fig. 1. An individual, exhibiting a contractile vesicle at a, and the position, 6, at which another has just collapsed. The large sphere e at the lower part of the figure is a vacuole containing a Eotifer ■which has just been swallowed. In the interior, diatoms and other food materials may be seen. 250 diameters. China Lake, Uinta Mountains, Wyoming, August, 1877. Abundant at the locality. Fig. 2. Individual with comparatively few and short rays, a, contractile vesicle ; 6, position at which one has just collapsed ; c, large vacuole containing a Kotifer in the act of being swallowed ; d, act of discharging effete matter. 250 diameters. Ditches below Philadelphia, with Lemna, Wolffia, etc., fcequent, April, 1877. Fig. 3. A small individual with long rays. 250 diameters. Lake. Hattacawanna, Morris County, New Jersey, March, 1875. a, contractile vesicles. Fig. 4. Individual with only five rays. Shortly after being noticed other rays were produced, and in an hour subsequently numerous rays extended in all directions, a, contractile vesicle ; c, food in the act of being swallowed. 200 diameters. Pond in Fairmount, Philadelphia, September, 1875. Fig. 5. Small individual with few rays, a, large contractile vesicle. 250 diameters. Ditches below Philadelphia, September, 1875. Fig. 6. A remarkable rayless individual, containing a Eotifer and other food materials, which were subsequently discharged, when the animaj assumed a more regular spherical form. 200 diameters. Found with the preceding. Fig. 7. Portion of an individual magnified 1,000 diameters, a, contractile vesicle; 6, nucleus. Fig. 8. An unknown Heliozoan, suspected to pertain to Actinosphserlum. 500 diameters. Marsh at Bristol, Pa., August, 1876. Figs. 9, 10. Anomalous body, suspected to be a detached portion of an Actinosphserium. 500 diameters. Ditches below Philadelphia, April, 1876. Fig. 11. Areolated body, suspected to be a moult of an Actinosphserium. 100 diameters, Abse- com pond, New Jersey, March, 1876. Similar bodies occasionally found and suspected to be related with Actinosphaerium. Perhaps it is entirely foreign to the latter and may be a vegetable product. Fig. 13i A portion of the same magnified 200 diameters. us CECLOGICAL SURVEY OF THE TERPITOBIES. PL.\TE XLi ,,^ r- ' r // \ X r <;^C> '^ f^"^^!iSr^4 ,.J3^ '<■ ■* "% ^^«;jf^ w»=Kas-^ "■^^-^-J ^■~ a- 3^,^.:^.%_^-: -'#■■' Mif-me"^ ■«jp.»ev 3.t==«=H ACTJNOSPPIAERIUM EICHHORNII. i PLATE XL II. EAPHIDIOPHRTS ELEGANS. Fig. 1. A group of twenty indiyiduals, associated by narrow isthmus-like tands. From a spring in which grew water-cress, near Darby, Delaware County, Pennsylvania, May, 1874. 250 diameters. Fig. 2. A more compact group, in which the isthmus-like connections were comparatively few. Same locality. 200 diameters. Fig. 3. A group of three individuals, part of the group of fig. 1. 500 diameters. Fig. 4. Part of a group, which consisted of thirty-eight individuals. 500 diameters. Fig. 5. An isolated individual in the act of takinga zoospore of an alga. 1,000 diamcteis. Col- lected with the preceding. Fig. 6. A group of nine colorless individuals. Abs^com pond, New Jersey, September, 1874. A similar group of fifteen was observed. 500 diameters. PLATE XL! W '^ \ 11 ^? J^ ^7 ^%; I j "^///'-y " X y -Z' T*^'::, .^(^ * X\ "*i^. / t SiliclMr*Son,Li- RAPHIDIOPHRYS ELEGANS i PLATE XLIII. Figs. 1-6.— ACANTHOCYSTIS CHiETOPHOEA. Fig. 1. A green indivitlual. Cominon form, in the vicinity of Philadelphia, among vaiioos aquatic plants. Ditches below Philadelphia, September, 1874. 750 diameters. Fig. 2. One of the longer furcate spines more highly magnified. Fig. 3. One of the smaller furcate spines more highly magnified. Fig. 4. A colorless individual. Less common than the former variety. Swarthmore brick-pond, Delaware County, Pennsylvania, May, 1874. 1,000 diameters. Fig. 5. An elliptical form, supposed to pertain to the same. Absecom pond. New Jersey, Septem- ber, 1874. 27.5 diameters. • Fig. 6. Supposed shed capsule, containing a few green grains and a brownish ovum-Uke body. Fort Bridger, Wyoming Territory, July, 1877. 250 diameters. The capsule was crowded with long and short furcate spines like those of the figure. Figs. 7-12.— ACANTHOCYSTIS ? With simple spines. Fig. 7. Bright green individual. Fort Bridger, Wyoming Territory, August, 1877. 750 diameters. Fig. 8. Green individual. Fort Bridger, July, 1877. 500 diameters. Fig. 9. A bright red individual. Spring on Darby Creek, Delaware County, April, 1875. 700 diameters. Fig. 10. A colorless individu.il. Atco, N. J., October, 1877. 666 diameters. Fig. 11. Colorless individual. Broad Mountain, Pennsylvania, September, 1876. 500 diameters. Fig. 12. Colorless individual, with the protoplasmic mass in an encysted condition, enclosed in a spinous capsule. With Ceratophyllum, from Bristol Canal, Pennsylvania, December, 1877. 666 diameters. Fig. 13. Fragment of membrane, supposed to be a portion of a moulted capsule of Acanthooystis. Fort Bridger, Wyoming, August, 1877. 500 diameters. Figs. 14-16.— ACANTHOCYSTIS ? With short pin;Uke spinas. Fig. 14. Individual, with the interior occupied by a mass of protoplasm com aiuiug a nucleus and a vacuole, but emitting no pseudopodal rays. Fig. 15. An individual with the protoplasm contracted into a baU, floating In a thinner liquor, and exhibiting at the periphery three vacuoles. Fig. 16. An individual with the interior protoplasmic mass apparently ready to assume tha encysted state.^ All three specimens collected with others in a pond in Fairmount Park, West Philadel- phia, August, 1878. 663 diameters.- S '"EOI.OGICAL SURVEY OF THE' T 'ERRITORIES, PLATE XL in i Leidy 11*^1 6. ACANTHOCVSTIS e-HAE'TOPHORA-. 7-16 ACANTHOC "S T , S PLATE XLiy. CLATHEULINA ELEGANS. Fig. 1. Individual with yellow latticed slioll and stem, and interior sarcode ball emitting nmner- ons rays. Absecom pond, New Jersey, October, 1875. 1,000 diameters. Fig. 2. Specimen of two individuals, the younger with its stem attached to the head of the older. The latticed head of the latter occupied by a large sarcode ball emitting numerous rays, the bases of which together with the ball enveloped in a diffused pale granular stratum. The sarcode mass of the younger head containing large globules. Found among Utricularia, Absecom, N. J., 1875. 750 diameters. Fig. 3. A young specimen, in which the latticed condition of the shell was not distinguishable. 1,000 diameters. Found with the preceding. Fig. 4. A still younger individual than the preceding. 666 diameters. Found together with groups detached from the under side .of leaves of the White Pond Lily. Hammonton pond, New Jersey, October, 1877. Fig. 5. A small group in outline. Same locality. Fig. 6. Specimen with the sarcode forming a c[uiescent ball in the interior of the uncolored latticed head. Found floating in water from Absecom pond, New Jersey, October, 1875. 1,000 diameters. Fig. 7. Colored specimen containing two sarcode balls. Sphagnum of Absecom, N. J., February, 1875. 1,000 diameters. Fig. 8. Colored specimen containing two sarcode balls. Hammonton pond. New Jersey, October, 1877. 666 diameters. Fig. 9. Specimen of two individu.ils, with the sarcode encysted in both. Absecom pond, New Jersey, November, 1874. 1,000 diameters. U-S, GEOLOGICAL SURVEY OF THE TERRITORIES. PLATE XLT/ Jos Leidy, Del CLATHRULINA ELEGANS. I PLATE XLY. Figs. 1-3.— HETEKOPHEYS ? ; Fig. 1. Individualfromsphagnous swamp, Broad Mountain, Pennsylvania. 500 diameters. Fig. 2. Individual, from Uinta Mountains, Wyoming, July, 1877. 1,000 diameters. Fig. 3. Individual, associated witli the last. 500 diameters. Fig. 4.— HETEEOPHEYS ? From spbagnum--water, Vineland, N. J., August, 1876. 400 diameters. Figs. 5, 6.— HETEEOPHEYS ? Successive views of the same individual. Uinta Mountains, Wyoming, August, 1877. 1,000 diameters. FiGS.7,8.— CIPLOPHEYS AECHEEI? Two views of the same specimen. Swamp-water, Broad Mountain, Pennsylvania, Septcmljer, 187C. 500 diameters. FiG.9.— HYALOLAMPE FENESTEATA. From sphagnum, Absecom, N. J., June, 1877. 500 diameters. Figs. lO-lC— VAMPYEELLA LATEEITIA. Figs. 10, 11. Two views of the same individual ; the former as first observed, the latter as seen two hours subsequently. Fort Bridger, Wyoming, August, 1877. COO diameters. Fig. 12. Individual, from Absecom pond, New Jersey, September, 1875. 800 diameters. Fig. 13. Individual, found with that of figs. 10, 11. 500 diameters. Fig. 14. Individual, ftom Fort Bridger, Wyoming, July, 1877. £00 diameters. Fig. 15. Individual, containing bright green alga3. Spring on Darby Creek, Delaware County, Pennsylvania, April, 1875. 500 diameters. Fig. 16. Individual, from bog- water, Longacomiug, N. J., October, 1874. 800 diameters. Figs. 17, 18.— HYALODISCUS EUBICUNDUS? Fig. 17. Individual, from ooze of Cooper's Creek, Camden, N. J., May, 1874. COO diameters. Fig. 18. Individual found with the preceding. 1,000 diameters. -i^i^:2!^2^1£^l^l^URVEY OF THE TERRITORIES PLATE XD/: Joa Leidy Del 1-6 HETEROPHRYS^ 7-8 DiploPHRYS ARCHERI^ 9 HYALOLAIvlPE FENESTRATE ■iO -16. \^^P-,T?ELLA LATERITIA^ 1? 18 ffiALODISCUS RUBICUNDUS? PLATE XLVI. Fig. 1.— EAPHIDIOPHEYS. Probably B. virUu. An individual svliich appeared bright green under lower powers. Ditches below Philadelphia, June, 1874. 370 diameters. Fig. 2. A nearly colorless individual. Same locality. 500 diameters. Fig. 3. A colorless individual. Found with Spongilla, in SchnylMU Eiver, Philadelphia, August, 1874. 500 diameters. A more highly magnified spicule seen in the left. Figs. 4-6.— HETEEOPHEYS MYEIAPODA ? Fig. 4. A bright gxeen individual, excepting the color, closely resembling an Aclinophrys sol. Ab- secom pond, New Jersey, May, 1877. 350 diameters. Fig. 5. A bright green individual. Vinelaud, N. J. , August, 1876. 500 diameters. Fig. 6. A bright green individual. From sphagnum-water. Absecom, N. J., May, 1877. Figs. 7-10. -HETEEOPHEYS ? Fig. 7. An individual showing a very great variability in the condition of the rays. Absecom mill-pond. Now Jersey, September, 1874. 500 diameters. Figs. 8, 9. Two views of an individual exhibiting successive changes of shape. Found with the former. 1,000 diameters. Fig. 10. A bright pea-green individual, with changeable form of body. Absecom pond. New Jersey, May, 1877. 250 diameters. Figs. 11-13.— HETEEOPHEYS ? Probably of the same species as the former. Fig. 11. A green individual, containing segments of Lyngbya, which have become red as a I'esult of digestion. 1,000 diameters. Ditch at roadside, near Darby, Pa. Fig. 13. A small individual, containing a large body, probably food, of . unknown character. Broad Mountain, Pennsylvania. 500 diameters. Fig. 13. An individual, containing apparently a number of unicellular algiB varionsly colored. Found with that of fig. 11. 1,000 diameters. U.S.GEuLOGICAL SURVEY OF THE TERRITORIES. 'I \\\.\A| PLATE XLVr )f:t^f>. r f^-^ T-^ o y^Tv-Tp^ /i(% / / 1' •>■-■ i' ;#-■- -^ j" ■■■- (3 ' i-'^'f •*^'«5 w /> cs Leidy. Pei Trujn SinclBiir-ii Son. Lith \'3 RAPHIDIOPHRYS 4-13 HETEROPHRYS. PLATE XLVIL Figs. 1-4.— GEOMIA TERRICOLA, Fig. 1. Individual with a multitude of extended pseudopodal rays forming an intricate net. The body of the animal has attached posteriorly a quantity of sand .and dirt. From among moist moss, in company with Rotifers, &c., in crevices of the pavement in the yard of my house, Philadelphia, June, 1874. 200 diameters. Fig. 2. A second individual found in company with the former. Fig. 3. A third individual with few pseudopodal extensions. Also found with the preceding. The arrows indicate tho course of currents of the protoplasm. 200 diameters. Fig. 4. Portion of the pseudopodal rays of a Gromia more highly magnified than in the preceding. The arrows indicate the course of flow of currents of the protoplasm with granules. As seen under Hartnack's No. 11 immersion objective lens. Figs. 5-12.— BIOMYXA VAGANS. 250 diameters. Figs. 5, G, 7. Three successive views of the same individual. Figs. 8, 9. Two successive views of another individual. Fig. 10. A third individual. This and the preceding specimens, from sphagnum collected at Absocom, N. J. , in the autumn and preserved in a glass case during the winter. March, 1875. Figs. 11, 12. Two views of an individual, exhibiting successive changes of form. From Sphag- num, Broad Mountain, Pennsylvania, September, 1876. us GEOLOGICAL SURVEY OF THE'TERRITORIES PLATE XLVIL J Leidy. H'el Tho« 6u-.clajrA, Son. l.i i - 4^. GROMIA TERRICOLA, 6 -IS. BIOMYXA VAGANS. PLATE XLVIII. BIOMYXA VAGANS. 250 diameters. Fig. 1. Large individual, containing many minute contractile vesicles together with a number of Closteriums. The larger circular spaces are vacant and were produced by the closing of meshes of the l)rotoplasmic net. The arrows indicate the course of the protoplasmic currents. From sphagnum, of Absecom, New Jersey, collected in the autumn of 1874 .and preserved in a glass case during the winter. Observed March, 1875. Figs. 2, 3. Two successive views of a small individual, found with the former, and supposed to bo a detached fragment. Figs. 4-6. Three successive views of an individual. Observed in the same sphagnum as tho foimer. Figs. 7-9. Three successive views of another individual. Also from the same sphagnum. Figs. 10-14. Five successive views of an individual. Fiova sphagnum of Broad Mountain, Penn- sylvania, September, 1876. Figs. 15-17. Three successive views of an individual. From sphagnum of Atco, N. J., April, 1877. Figs. 18-20. Three successive views of an individual. It contained a distinct granular nucleus, and is suspected to pertain to the same organism as the former specimens. Found with the preceding in sphagnum of Atco, N. J. Fig. 21. Supposed to be a condition of Biomyxa. It contains a nucleus, several contractile vesi- cles, and numerous darkly defined granules. Figs. 22-25. Four successive views of another individual of the same kind. As first seen, fig. 2, the creature discharged a large mass of oxcrementitious matter. The subjects of figs. 21-25 were found, with many others of the same kind, together with multi- tudes of minute desmids, in a clear gelatinoid substance, adherent to the glass case in which was i>re- served a 'arge bed of sphagnum, collected in the autumn at Absecom, N. J. April, 1877. us GEOLOGICAL SURVEY OF THE TERRITORIES PLATE XVmi -—-^ - J*' o° 25. OS Leidy. Dsl BI01vfj^C/\ Vi^G/J-lS.