' ^ \ ^-''' ,i 1893 j ,^ ^— /^ '^ Tylenchus and Root-gall. (With twenty original figures, on wood, drawn with the camera lucida. ) By N. A. COBB. Life Histohy op Tylenchus Arenaeius. To the Director of AgriouUiire, Sn-, Pretty Oully Scrub, 2t) April, 1890. ' I send you u sninll potato showing a disease or parasite that affects the skin. It comes in small knobs at first, and gradually spreads over the potato. I think it is some insect in the ground, as it comes on the roots of the potato first, like knots on a stout thread. On about an acre and a half of ground I sowed two bags of lime and one bag of salt, but it had no effect. It has been in my paddock for the past four or five jears, and is constantly growing worse. It affects parsnips, maiigels, and the roots of the peach trees, and I have seen it on the roots of large Swede turnips ; and I am inclined to think it kills the newly sown turnip. I have sown turnips three times since February ; after coming through the ground they gradually grow yellow and die off. The last time I dusted them with lime just after they broke the ground, but it did no good ; they died off like the rest. My soil is rich scrub land, and I manure it well. It has been under crop for the last twelve or fourteen years. If there is any practical remedy will yon oblige by letting me know at your earliest convenience. I enclose some of the "soil with the potato. Yours respectfully, William EASsoy. In accordance with Mr. Eas.son's suggestion that it was au insect pest that was giving him so much trouble, the specimens accompanying the foregoing Tetter were forwarded to the Consulting Entomologist of the Department, who reported that the disease was certainly not due to the attack of any insect. The specimen was therefore forwarded to me. After a short examination I wrote to the Director of Agriculture that although the specimen was not such as to permit me to say with certainty, yet from what Icould discover, and from Mr. Easson's description of the manner in which his various crops were afl'ected, I had little doubt that liis land was infested with a destructive Nematode worm, similar to that which has proved so disastrous to the sugar-beet crop in Europe, and that if my suspicion was correct, it was important that the matter be at once and thoroughly investi- gated; and concluded by desiring that further specimens, both of various diseased roots and of surface and sub-soils, should be forwarded to me for further examination. In accordance with my request Mr. Easson forwarded various samples, as will be seen by reading the following letter: — To the Director of Agrieid(vn-e. Sir, Pn-tty Gully .Scrub, 19 May, 1890. I have sent by this nnvil two packets containing samples of soil and root-s — potato, parsnip, and peach-tree roots. The disease can bo clearly seen on the parsnip and potato, and a little on the peaeh-ttco roots. I have seen it nnich thicker on peacli-tree roots than on the sample. The potato is taken from four drills planted about Christmas. They were well dunged with pig-sty manure. The potato was planted on the dung, then covered, then a bag of lime sown on the top in the drills, then covered over again. The four drills were al>out 200 yards long, so I think they had a fair trial of limcj but it ha. Such a specimen is shown in Fig. 3. Its dimensions were as follows: \i % '.j'5 ic'i "'o- ■ '42 mm. Secondly, the entrance into root tissues is accomplished at an early age in an allied species. The mecnanism by means of which the larva) make their way into the roots and rootlets of plants, namely the spear and the median oesophageal bulb, Fio. 2. T. arenarius. I, the larva X 200 ; II, liead of same x 900 ; III, bit of the middle of tlie body X (iOO ; IV shows at the centre tlie actual len^tli of the womi ; s, the spear ; b, the bulbs ; n, the nerve-ring ; i, the intestine ; c, cuticula ; /, lateral fields ; a, anus. 160 Agricultural Gazette. Fio. 8.— Larva of T. are- narius akter enter- iKo A Boot, x 100. 8, spear ; b, median bulb ; V, ventral ^Innd which empties tlirougli the excretory pore p ; a, anus. are shown in the figures, and their structure has already been commented upon. The larva makes its way to a rootlet, applies its mouth, and exerts a powerful suction by means of the muscular median bulb, at the same time thrusting forth its spear by means of appropriate muscles. The cells of the epidermis of the rootlet are thus pierced, and are then sucked dry and made to collapse. At the aperture thus made other and deeper cells are similarly attacked. Continuing this lino of action, the worm makes its way into the interior of the rootlet. At least, such I believe to be the method of attack, although I must iidd that my opinion is deduced from the structure of (ho organs of the worm and the effects on the tissues of the plant. I have not witnessed the actual entrance of a larva into a rootlet. Once within the rootlet, the worm is in the presence of an abundance of food, and begins to grow apace. Here again it brings into play its piercing and sucking apparatus. Its very existence depends upon these organs, and their importance is attested by the fact that throughout the life of the worm they remain in perfect condition, although numerous other organs become completely degenerate. By continually thrust- ing forth the sharp spear the juicy cells of the rootlet are pierced, and their contents are then sucked in. The growth of the larvae consists in a rapid and great increase in diameter, so that the originally slender worm soon takes on the plump form shown in Fig. 3. The tail and head alone retain somewhat of their original size and form. Even the tail disappears at a later stage. Whether the change now to be described takes place at the first moult, I cannot say. Eeasoning from the size of the larva, I should answer iu the affirmative. It is certain that at an early stage, shown in Fig. 4, the worm undergoes a change in which the tail disappears and, a])parently, the anus with it. Fig. 4 represents then, we will say, the first or second moult. The old skin is shown, and inside it the larra. It is evident that the result of this moult will be a tailless worm. The porous excretorius and the duct are also clearly shown in the figure. The excretory appa- ratus, therefore, persists, as does the muscular system. That the struc- ture of the spear and oesophagus remain essentially unaltered is suffi- ciently attested by Fig. 5, taken from a worm of about the same size as that shown in Fig. 4 ; there is no alteration except that the whole structure has increased in size, and, therefore, in effectiveness. Up to this time the sexes remain indistinguishable or nearly so, but at this st.Tge the life-histories of the two sexes begin plainly to diverge, and present, from a biological point of view, a most interesting series of phenomena. Let us first cons-idcr the history of the female. Fig. 4 represents a female, the first clear indication of the sexual organs being exnibited in the single coll at o. This cell, by dividing, soon gives rise to Fio. 4.— Moui/ri.vo Larva op T. arenarius. x 100. c, old skin ; s, spear ; v, ventral f^Iand which emp. tied through excrctorj* pore p ; b, median hull) : 0, rudimentary se.xual organ. Fig. 5, — Neck and Head OK Fio. 3. x 200. jr, spear; b, median bulb ; p, excretory poro. Jfew South Wales. 161- a tvvo-i)arted. sexual system — consisting of a vaj^iua, two uteri, and two ovaries, — which grows to such an extent as finally to occupy tlie greater part of the body. The complete history of its development I have not yet been able to follow, simply from lack of time. 1 think it presents no unusual diilicultics. At the same time that the sexual organs are grow- ing so vigorously other parts of the organism are pursuing an opposite course. As already pointed out, the anus disappears at the first or second moult. Soon all of that portion of the elementary canal behind the oesopha- gus undergoes a degeneration and disappears. The spear and oesophagua alone remain intact. The muscular layer lining the cuticula also disinte- grates. We have, as the result of this growth on the one hand and degeneration on the other, a sac consisting of the cuticula of tlie worm, almost comjdetely filled with a two-parted egg-producing api)aratus, and supplied with nourishment by means of powerful sucking-organs. If now wo turn our attention to the development of the male we find a very different history. No one would have ventured to predict such a remarkable series of changes as we have now to follow. A parallel rase is known but for a single animal species, the closely allied Heterodera {Tylen- clius) Schachlii, 8chmidt. As before remarked, up to the stage represented in Fig. 3, tlie sexes are with difficulty distinguished from each other. But thereafter the history of the male is totally different from tiiat of the female. If the larva shown in Kg. 3 be a male, its next moult gives rise to a slender worm of the form shown in I, Fig G. This remarkable moulting condition is showr. in III. Fig 0, where the slender young male is represented as several times coiled inside its former skin of very dif- ferent shape. By its constant activity it at last succeeds in rupturing the old skin — not, however, before it has again moulted — and issues a distinct male with all the sexual organs complete. In this condition, which is the adult male state, measure- ments give the following formula: ^'; ';^ ."' " ^'^ 1-33 mm., in which 88 is the measurement to the centre of the median bulb, inasmuch as I have not been able to satisfy myself as to the exact position occupied by the nerve- ring. The cuticula, like tliat of the female, is devoid of hairs and presents about five hundred transverse strise. The conoid neck terminates ni a truncated head bearing no cephalic seta;, but armed with six distinct, rather hemispherical or conoid lips. 1 could discover on the only two specimens examined no papilhe. lateral organs or eye-spots. The spear is rather stout for its length, being, no doubt, a very effective organ. That portion of the opso])hagus in front of the powerful pro- late or ellipsoidal median bulb is one-fourth ;is wide as the neck and is lined with tiiick, glistening, chitinous walls. The median bulb itself is two-thirds as wide as the adjacent part of the neck and also presents a chitinous lining in the form of a central apparatus one- fifth as wide as the bulb and of the same form. The intestine is at least two-thirdM as wide as the body and its cells are jiackcd with fine granules ; it tcrminales posteriorly in a rectum twice as long as the anal diame- ter. The tail is obliquely hemispherical-conoid and Fia. 6— Male of Oaii;- WORM (T. arenaHvt), I. mature male, x 65 ; II, head of same, x 460: in, larval male, inside of its cast off skin, X 50; IV and V, cross and lon- Kitndinal sections, x SBO; VI. lateral and veutnd view of tail, x 22S : >, spear ; h, bulb."* ; i, intcs* tine ; az, spermatozoa ; r, cuticula : V, vas deferens; rf, end of ductus ojacula- torius ; ps, penes or spi- cida ; a, anus. 182 Agricultural Gazette. presents a rounded terminus, which, inasmuch as the tail is destitute of glands (?), contains no aperture. The anus is not conspicuous and there is 710 sign of a bursa. The two equal, linear, acute, nearly straight spicula are wider and fusiform in the proximal third and are about twice as long as the tail or considerably longer than the anal diameter.* There are traces of accessory organs. The ductus ejaculatorius seems to be at least three to four times as long as the spicula. The testicle (or testicles ; 1 do not know whether the male apparatus is single or double) appear.s to extend forward to near the median oesophageal bulb. The spermatozoa are large and spherical with conspicuous darker nuclei lying in the centre of tlie i-emaining trans- lucent protoplasm. IV Fig. 6 represents a cross-section of the male taken from the region of the vas dcforeus, and shows the spermatozoa in situ, and also the size and relative position of the intestine. The left side of the figure is dorsal. It only remains to say, concerning the structure of the male, that the tail, when seen in the dorsal or ventral aspect, presents a different contour from that shown when it is seen in profile, appearing in the former case to be somewhat concave-conoid. Prom the foregoing description it will be seen that the males resulting from the moult in which the remarkable change of form occurs, are in all respects mature, being supplied with testicles and eopulatory apparatus. "With regard to the copulation I will venture to offer one or two suggestions. It is manifest that if the mature male had the form shown in Fig. 3, he would be much less perfectly adapted to making his way through the tissues of the root in which he has developed than if his form were a more slender •one, and I can have no doubt that this fact explains the remarkable return to a slender form, shown in Fig. G. The female, so far as I know (and I have examined quite a number, perhaps twenty), continues in the course already indicated — that is to say, never returns to a slender form, but, con- tinuing the line of development shown in I, II, III, Fig. 1, becomes a motion- less sac, whose sole object is the production of eggs. It wouldseem, then, that the copulation must take place inside the tissues of the ])lant infested, and that the males are enabled, by their return to the slender form, to make their way about in search of their obese and motionless female companions. The only other tenable hypotliesis is that the males leave the plant, and that copulation occurs in the soil. This supposition Las nothing in its favour ■which is not also in favour of the first supposition, and against it may be set lip the two following suggestions : — (I) The female is not known to return to a slender form, and probably, after having once entered a root, never returns to the soil. (2) If the female docs not return to the soil (and I must regard this as fairly well established by my observations) the only copulation that could occur in the soil would be between the males which Jiad made their way outward and the females which had not yet entered. 'These females, however, do not, so far as I have observed, possess a vulva or jinj sexual apparatus beyond a rudiment consisting of a single cell, and are therefore i)ieapabie of copulating. What dim light my researches have shed on the subject compels me therefore to adopt the supposition that the males on assuming the slender adult form seek out and fertilize the females lying in the surrounding tissues. This supposition is possibly fortified by the fibsence of a bursa in the male, though I am not certain that the argument possesses much force. The fact is that the allied species {Tylenchi) possess a more or less complete bursa. There are reasons for regarding the bursa as a structure whoso function is the attachment of the male to the female * The reader will hove trust the text and not the Illustration, Fig. C (p s) gi\ cs but a poor idea of the Jippearance of the spicula. J^ew South 'Wales. 1G3 during copulatiou. If, however, the female were tightly held by the tissues of the root ia which the copulation was to take place, it is easy to believe that a bursa would be of little service, and it might therefore disappear in the course of time because superfluous. Fortunately I am better prepared to discuss the result of the fertilization. The ova in the uterus of the female, once they are fertilized, develop and surround themselves with a shell. The consequent increase in the size of the sexual organs causes them to fill a large proportion of the space contained in the sac-like body. Even when the worm has reached the proportions shown in II, Pig. l,the ovaries and uteri occupy fully half the available space and the blind ends of the ovaries may often be seen projecting into the narrower part of the body. The remainder of the worm is filled with spherical clear spaces, the interstices among these spheres being filled up with granules. When the female has reached the mature stage represented in III, Fig. 1, the sexual apparatus occupies an even larger proportion of the body cavity. The eggs have the form shown in Fig. 1, and have in many cases begun segmentation before they arc deposited. The first two steps ia the segmentation are shown in the figures. In accordance with the rule obtaining in the group Nematoda, the first two segments arc unc(]ual, though in the present case less unequal than usual. Of the first two segments, one begins to divide faster than the other, and gives rise to the exterior layer of a gastrula-like structure, while the other, dividing more slowly, gives rise to the internal cells of the same gastrula-like structure. The rapidity with which the segmentation goes on is in some degree indicated by the following experiment. On first receiving the Pretty Gully Scrub material, I placed some eggs in a moist chamber of i)eculiar construc- tion. They were then in the first stages of segmentation. At the present time, three weeks later, they have reached the gastrula stage. It will there- fore be seen that, provided the experiment be not deceptive, the embryonic life extends over a considerable period. The experiment needs, however, to be c mtrolled by others before anything very positive can be said concerning the period of incubation. It is well known that the rapidity of segmenta- tion in certain Nematodes varies widely according to the external conditions. A word remains to be said with regard to the time and manner of deposit- ing the eggs. Here again I must call attention to the incomplete state of iny observations. So much is certain, that a relatively large vulva or sexual opening exists at the posterior extremity of the mature female. This appears as a flat conical projection, and is illustrated in the figures I and II, Fig. 1. In the neighbourhood of the vulva the surrounding root-tissue is usually of a yellow colour, and in this yellow tissue are uniformly to be found eggs, many of which are in the first stages of segmentation. I have also seen eggs well advanced which were still in the uterus. There seems, therefore, to be no great uniformity in the state in which the eggs are laid. But this important fact is established beyond doubt, namely, that the eggs are deposited in the root-tissues. Doubtless also they remain there until liatched. The larva) must then either remove to fresh parts of the same root or, what is more probable, make their way into the soil in search of now rootlets. I assert the greater probability of the latter course for the following reasons : — The result of the attacks of the worms is abnormal tissue, and this is known sooner or later to decay. Therefore it follows that tissue already attacked is not an altogether suitable habitat. Moreover, old tissues are more or less impenetrable to the larva>. They find their proper entrance only in the tender rootlets. Again, the larva) are found iu Agricultural Gazette. abundance in the soil, showing that many must have left the tissues in which tiiey were hatched. All tins, however, does not preclude the supposi- tion that some larvas may simply move to a different part of tlie root in wliich they eoininenced their existence and there develop. I merely wish to point out that this is far less probable than that tlicy attack fresh rootlets. I have now related what I have learned concerning the life-history of this pest. Much remains to he done, and considering the extent of the devastation caused by allied worms in Europe and the United States, it is to be hoped that the remainder of the investigation will, in duo time, be made. The importance of following the pest througli the seasons of an entire year cannot be too strongly insisted upon. The manner in which this should be done is already indicated, and will now be still further elucidated. The exact time of year, if any exist, in which the larva) issue in greatest numbers from old roots, and begin their migrations to fresh rootlets, should be ascertained. The manner in which the worms are spread from one field to another should be investigated. It is also important to ascertain whether or not the eggs or larva) pass iniinjurcd through the alimentary canal of domestic animals. If they are not injured by that process, manure is likely to become an agent in distributing the pest, for it is perfectly certain that root-crops injured by the worm will be fed to animals. Numerous researches, therefore, remain to be made before the pest can be said to have been properly investigated. Systematic. Although the foregoing observations are inadequate as a picture of the life history of this worm, they are quite sufficient to indicate its systematic position. Beyond doubt it must be referred to the genus Tylcnchus, a genus already known to contain some of tlie worst enemies of various crops. Ti/hnchus tritici causing a serious disease in wheat, and Ti/lenclms devastatrix, which often sweeps off the onion crop in Europe, may be cited as instances. My reasons for assigning this vi-orm a place in the genus Tylenchus must be given in full, for they affect also the systematic position of a number of worms heretofore reckoned as belonging to a distinct genus, Heterodera. The characteristics of the genus Tylenchus may bo briefly given as follows : — Transparent striated round worms, totally devoid of bristles or setfP, varying in length from one-third of a millimetre to three and a half millimetres, attacking the tissues of ])lants, or more rarely animals, by means of a s])car and sucking ap])aratus of the following construction: A three- bulbed spear, capable of being thrust forth and withdrawn by means of appropriate muacles, is connected wdth a powerful median esophageal sucking-bulb by means of a tube whoso lining is more chitinous than is usual in other Nematode genera; the median bulb is connected with a smaller posterior bulb of much weaker construction by means of a shorter and weaker tube, which passes through the oblique nerve-ring, situated just behind the median bulb. The posterior bulb may become quite rudimentary, but probably never quite disap|)ears. Lateral organs as well as visual organs are unknown in the genus. The female sexual ai)paratus is usually single and asymmetrical, being in that case usually straight and directed forward and often presenting a rudimentary posterior branch, but may be double and symmetrical. In the former case the vulva is behind the middle ; in the latter case it is central. The male possesses two etiual, arcuate spicula and a more or less well-developed bursa. Prom this characterization I have puiposely omitted the changes that it will be necessary to make when the present worm and its allies are added to the genus. J{ew South Wales. 165 It will be Been that the worm under consideration harmonizes with this characterization with slight exceptions. The male of the present worm has no bursa ; but I cannot think this an objection to calling it Ti/lenchus. The bursa is very variable in Tylenchus, msomn cases enveloping the tail completely, and in others extending only a short distance on either side of the anus, being in the latter case quite rudimentary. That it should fail completely cannot be regarded as even remarkable. Again the present worm presents a history, not hitherto admitted in the genus Ti/lenchus ; but the remarkable change to the flask-like form is due merely to the degeneration of the digestive and muscular tissues on the one hand and an unusually luxuriant growth of the sexual organs on the other. The morphology of the animal is, it is true, thus obscured, but it is not materially changed. One never thinks of excluding certain species of Ithahdilis from (he genus to which they properly belong, merely because the young, as is often the case, finally rupture the uterus, and, entering the body cavity, devour its contents, and by growth finally give the body-wall of the mother-animal a bloated appearance. These two facts, the absence of the bursa, and the jieculiar life-history consequent upon a truly parasitic life, are the main grounds for placing our worm in a genus separate from 'Ti/lenchus. Against these two objections, which are in reality slight, may bo sot up a vast array of arguments based on the similarity existing between it and I'yhnclms. Let us consider in detail the exact proportions of a typical Tylenclms. For this purpose 1 iiave averaged the lormulffi of twenty species of this genus. The males of some of these species are as yet unknown, consequently I have first averaged the female forinulse, and with the following results : — (1.) Average female formula when the sexual organs are single, }!° ; ''i' ^'.' ^ 1-23. (2. ) Average female formula when the sexual organs are double, 'f* \ '" -^ — 7— 1 '4. From the males which are known the following averages are obtained : — (3.) Average male formula when the female sexual organs are single, J^^ — ' ''3'° 32 "ta ^- (4. ) Average male formula when the female sexual organs are double, 2 « ? '8 JJ M 05-8 -^ .gg^ Imperfect as these formula; are, on account of our incomplete knowledge of many of the species, they serve to show at once the striking similarity existing between the worm we have under consideration and tlie typical Tylenclms. Compare the formula of the larva of the present species with the above formula), remembering always that the comparison is between a larva and adult forms, and that tho relative lengtli of tlie ojsophagus and tail and all their component parts will in the larva decrease with age, as will alec the relative width. It is evident at once that the resemblance is great in any case, and will ultimately be greatest between the worm whose alhnity we are trying to discover and those Tylciichi whose females have double sexual organs. This is true, whether we compare the formula of our larva with the female Ibrmuhc of Tylenclms or compare the formula of our adult male with the male formula) of Tylenclms. This result is all the more sig- nificant when we consider that the females of our species ultimately develop double sexual organs, and that species with blunt tails are relatively much more common in that group of Tylenchi whose females possess double sexual organs. There is not the slightest doubt left in my mind that we liave here to do with a Tylenclms belonging to the group with double female sexual organs, which has, owing to a truly parasitic life, taken on some very striking but truly slight new morphological characteristics. 166 Agricultural Gazette. Before settling the specific relations of our worm, it will be necessary to review the literature of the subject. There can be no doubt that the worms heretofore described under the generic name Jleterodera belong to the same generic group as that which we are considering. The resemblances to S. Schach/ii (Schmidt) are too great to be overlooked for a moment. Our species, however, is not Schachtii. On comparison of the larva; and males of the two forms, it is at once evident that Schachtii is a wider worm, with a spear of different proportions, and with a longer oesojjhagus. Differences also exist in the formation of the mouth. The relations with ][. radicicola, Greef and II. Jnvanica I cannot discuss, either on account of the incom- pleteness of the descriptions or the inaccessibility of the literature. A work by Dr. J. C. Neal, on what is called the lloot-knot Disease, has been recently issued by the Agricultural Department at Washington, TJ.S.A. The author describes a disease due to the attacks of a worm which he has pro- A'isionally named Ani/uillula arenaria. I have carefully examined the figures accompanying Dr. Ncal's report and am convinced that the worm I have examined is identical with that which he has figiu-ed. His figures are such that the examination has not been easy. What I take to be the male of Dr. Ncal's species, though he has called it a female (Plate XII, 6, Neal 1. c. 1 -v-tT -1 \ • Jl i! 1 S'2 8'? 13-0 M ? , 15 ? 23- M ( and XV, 1) gives the tormulse -^i — ji; ^.i — n — jr and -j:^ ts^m — T- His larvas give -r, — j — Ju — m— r- The great width of these figures I can attribute to pressure from the cover-slip. Otherwise there is a fair amount of correspondence between his figures and my own. It is, however, best to mention the following points. A. arenaria, Neal, is said to be indigenous in the United States. Its uteri often contain living and hatched embryos. The eggs arc said to escape by rupture at the anterior end. I think this is a mistake, and that Dr. Neal has shown the vulva in Plate XIX near the lower margin of his figure, and again more plainly in Plato XXI. Dr. Neal does not figure a bulb in all cases, but it may easily have been overlooked. As I have already stated, much of the work in the investigation of free-living Nematodes lies on the very verge of what can be accomplished with the best modern microscope. In no part of the paper is the s])ear mentioned as such, but I cannot help regarding the words " fissure having a circular hinge-like termination," as the author's interpretation of the Tylenchoid spear. Still I call attention to the fact that if I am right in this. Dr. Ncal's figures represent the spear as much larger than I have found it to be. The eggs are figured in the American pamphlet as straight, I have observed that they are usually slightly curved. In spite, however, of these minor differences, which are, for the most part, I think, to bo attributed to the American investigator's acknowledged unf amiliarity with Nematode anatomy, I can have no doubt that the Australian worm is the same that Dr. Neal has described as occurring in a belt of land one hundred and fifty miles wide extending from Texas through the Gulf and South Atlantic States, a distance of, say, two thousand miles. Tliis being the case, I shall for the present call the Australian worm, Tylcnchis arcnarius, Neal, with the remark that for aught I can say to the coutrary, it may bo T. (Ilclcrodcrd) radicicola, Greef, or T. (Iletcroderd) Javanicus. Dr. Bancroft, of Brisbane, has sent me an interesting pamphlet in which he describes and figures a root-infesting Nematode found by him on grape and banana roots. Dr. Bancroft's well-known familiarity with Nematode anatomy has enabled him to distinguish both sexes. His figures seem to represent T. arenarixis. J^ew Soioth Wales. 167 II. The Genus Tylenchtjs. (Character given on page 164.) Key when both Sbxes are knowk. Female sexual apparatus, dottble : — Page. Species leading a parasitic life in roots of various plants — (Esophagus of the larva 26 ; width 6 2 Schachtii 170 (Esophagus of the larva 18; width 3-6 3 arenarius 170 (Insufficiently known tome at this point are T. radioicola and T. Javanicus. ) Species leading a free existence-- Tail of female rounded at the end — Length of female 1-7 mm. ; width 2-5 4 robmtua 1/0 Length of female '75 m»'. ; width 4' 5 dubius 171 Tail of female conical — Cuticula with no very conspicuous wings ; spear stout 6 rjracilis 171 Cuticula with two lateral and four submedian wings ; spear slender 7 lamelU/erus 171 Female sexual apparatus, simple (single), often with a rudi- mentary posterior branch : — (Esophagus Tylcnchoid, i.e., with one or more bulbs ; parasitic in bees 1 bombi 169 QEsophagus Tylcnchoid ; if parasitic then in plants — Bursa of male completely enveloping the tail — Tail of female rounded at the end- Vulva 75'+ ; tail conoid 8 prateusis 171 Vulva 67' ; tail nearly cyliudroid 9 obtusus 172 Tail of female conical — Length -rA mm 10 terricola 172 Length 1" mm. or more — Spicula L-shaped 11 imper/cctus 172 iSpicula straight or arcuate — Accessory pieces aa long as the spicula .. 12 fungorum 172 Accessory pieces shorter than the spicula — (Esopliagus (female) 4-2 13 scandens 173 (Esophagus (female) 16-7 14 devastatrix 173 Bursa of male incompletely enveloping the tail — Length of tlie cesophagus indefinite ; tail 95' 15 velalus 174 Lengtli of the oesophagus definite — Anus 67' to 70-— Vulva central ; width 2- 16 leptosoma 174 Vulva GO- ; width So 17 Jili/onnis 174 Anus 84' or more — Neck 27- to 29— Vulva 83' ; spear 5-5 18 macrophalhis 174 Vulva 70- ; spear 2- 19 pillulifer 174 Neck 15 to 20— Spear stout ; conspicuously bulbed 20 Darainii 175 Spear weak ; inconspicuously bulbed — Width 29 ; bursa extending to middle of tail 21 intermedius 175 Width 2'1 ; bursa shorter 22 elegans 175 Neck 10- ; width 5- 23 A.'icula straight 12 funqorum 172 Spear distinct — Lengtii at least 2 mm. — Width 3-5 13 ncandens 173 Width 1-4 6 gracilis 171 Length 1 '5 mm. or less — Width about 4-— Cuticula with two lateral and four submedian wings 7 lamelli/erm 171 Cuticula with no such conspicuous wings 5 rlubi^is 171 Width 3' or less — Anus 97 "5 ; spear 4' 4 robiisltis 170 Anus 93'5 ; spear 1" 14 deva-itatrix 173 fSursa incompletely enveloping the tail — Anus about 67' — Width 3-3 17 fdiformis 174 Width 1-9 16 kiitoaoma' 174 Anus 85' or more — (Esophagus indefinite with no bulbs 1.5 velatus 1 74 (Esophagus de6nite — Neck 27- to 29 • — Spear large {5-5) ; spicula long 18 macrophallus 174 Spear shorter (2-) 19 pilluli/cr 174 Neck 20' or less — Width 5- ; oesophagus 10' 23 Askanasei/i 176 Widtli 3'6 or less ; oesophagus 15" or more — Spear stout ; conspicuously bulbed 20 Davainii 175 Spear weak ; inconspicuously bulbed — (Esophagus 15- ; tail 85' 22 ekgans 175 (Esophagus 20' ; tail 90- 21 hilermedlus 175 Mew South Wales. 169 Key to Females. Female sexual apparatus douhk : — Pasc. Tail and anus none ; saccate worms parasitic in roots — ]!ocly widely fiisifoi-m 2 SchaeUUi 170 Body ellipsoidal or spherical 3 arenarius 170 Tail rounded at the terminus — Length '75 ?«m. i (esophagus 18 5 dubius 171 Length 1 '70 TO?n. ; oesophagus 12o 4 robmlus 170 Tail conical — Cuticula with two lateral and four submediau wings ... 7 lamelliferva 171 Cuticula with no such conspicuous wings 6 (jracilis 171 Female sexual apparatus simple (single) : — CEsophagus Tylenchoid, i.e., with one or more bulbs ; parasitic in bees 1 hombi 1C9 OEsophagus Tylenchoid ; if parasitic then in plants — Tail conoid terminus not rounded — Neck only 4 '2 , 13 scandens 173 Neck 10 — Vulva 92- 12 funt/orum 172 VulvaSO' 23 AsLanaseiji 176 Neck 14 to 19— Vulva central 16 leptosoma 174 Vulva about 67 — Anus 70- 17 filiformis 174 Anus 85" or more — Length '54 »(7ji; width 4' 10 terricola 172 Length '85 mm. to \'mm. — Width 2-1 21 inkrmedius 175 Width about 3-— Spear 1 '2, hardly knobbed 22 elegans 175 Spear 19, distinctly 3-knobbed 20 Davainii 175 Vulva 80 or more — (Esophagus 14' ; vulva S8' 11 imper/ectus 172 (Esophagus 16'7 ; vulva 80' 14 devustatrix 173 Neck 27 to 29— Anus 92' ; vulva 83' 18 macrojihallus 174 Anus 85- ; vulva 70- 19 t>Ululifer 174 Tail ro\inded at the terminus — Vulva 75' + ; tail conoid 8 ^)i-a(en.sis 171 Vulva 67' ; tail nearly cylindrical 9 obtusus 172 CEsophagus Dorylaimoid, «.c. lachrymatoriform 24 mirahiliit 176 1. T. bombi, Dufour. The young of this remarkable species are worms about one millimetre long, living fi'ce in the soil, where they become mature and copulate. The fertilized females enter the bodies of hibernating bees, and there lead a parasitic existence, occupying either the body cavity or the wall of the alimentary canal. During the parasitic life the sexual apparatus pro- trudes from the vulva, and ultimately becomes a sac one and a naif millimetres long, to which is attached for some time the real body of the worm in the form of a small appendage ; but even this finally disappears. In this latter condition the animal first became known under the name of Sphcerularia bombi. The young, to the number of 50,000 to 100,000, hatch while still in the body of the host, but become sexually perfect only on entering the soil. 170 Agricultural Gazette. 2. T. Schachtii, Schmidt. V 'H Z^ e' » . «"•»• is the formula* for the freshly hatched larva?, of which the following is a further description : — Neck cylindroid to opposite the base of the spear, tlienco convex-conoid to the rather narrow but unusually prominent and projecting lip region ; spear bulbed at its base ; anterior part of the oesophagus a narrow chitinous canal, which leads to a muscular prolate bulb two-thirds as wide as the adjacent part of the neck ; nerve-ring close behind the bulb just mentioned ; remainder of the (esophagus apparently indistinct, certainly short ; intestine three-fourths as wide as the body, terminating posteriorly in a rectum one- third as long as the anal diameter; tail conical ; rudimentary sexual appa- ratus a little in front of the commencement of the 2)osterior third of the body. The larva?, which are found in the soil, make their way into rootlets of various plants by means of the special piercing and sucking apparatus (spear and bulb), and then undergo a remarkable metamorphosis, similar to that already described in the case of T. arenariiis, Neal. At an early moult they lose the conical tail, a shorter and rounded one taking its place. Meanwhile the body, amply nourished by plant juices, becomes plump, and takes on the dimensions shown in the following formula: — ^|? — "J).] — .; — j^?i — ^. The sexual organs now begin to develop, and the larva; become elongated sac-shaped. The female continues to develop in this manner, and becomes finally a motionless, widely fusiform sac, devoid of anus and with a terminal vulva. The two-parted female sexual a])paratus develops enormously, and at last fills the body of the worm completely. The number of eggs con- tained in it averages 300 to 400. These are deposited in the tissue of the plant attacked at a period when they contain well-developed embryos. The male, however, instead of continuing in the path of development followed by the female, returns to a slender form, having the following dimensions : — 'i- — ^F — '^r — J- — TT- The .structure of the head and oesophagus is quite similar to that of the newly-hatched larva). The tail, however, becomes nearly hemispherical. The linear-cuneiform spicula are arcuate and acute. There is no bursa and the testicle extends to the middle of the body at least. The change of the male to the slender form occupies at least five or six days. Nothing is known concerning the copulation. The eggs laid by the female are '04 x '08 mm. The males and females arc born in equal numbers, and the change from the egg to the adult state occupies from five to six weeks. This worm is the cause of a most serious disease in the sugar-beet. Por remedies, see those recommended for T. arenariiis. 3. T. arenarius, Neal. SufSciently described in the foregoing pages. Por remedies, sec section III. 4. T. robustus, De Man. 1 ^ ? '°;» f^^ "f r7mm. Ciiticula finely striated ; heterocephalous, lipless ; two lateral and four aubmedian chitinous edges (soon disappearing) found on the head ; spear very .stout ; median bulb ovate ; portis cxcretorius, at ten per cent. "T — ?' — ^r — i^ — T^ 1-3 mm. Neck, as in the female, diminishing considerably ; tail completely enveloped by the bursa, which presents two lateral papilla; on the post-anal part ; the short spicula accompanied by rod-shaped acces- sory pieces. This slow moving species is rather common in Holland, in soil penetrated by fresh or brackish water. * For an explanation of the formulie used in this report sec tlie fii-st number of tliis Gazette, p. 131. J^ew South Wales. 171 5. T.diibius.Biitschli. 1^ 'I "''* ^^ -T^mn. Cuticula presenting about «cven hundred fifty transverse striie. The rounded head is destitute of papilla) and lipless, although a lip region is set off by constriclion ; prolate median bulb central, one-half as long as the adjacent part of the neck is Avide ; conoid posterior swelling nearly as wide as' the intestine, which is two- thirds as wide as the body and composed of cells loosely packed with granules ; porus excretorius at twelve per cent. ; tail cvlindroid, diminishing at last. Tail, unlike that of the female, conical and completely enveloped by the bursa, which extends far enough forward to be symmetrically arranged with respect to the anus, and presents at the middle of the tail a pair of ribs extending nearly to the margin ; a single indistinct median papilla opposite the proximo; of the linear spicuJa; these latter nearly two-thirds as long as the tail, arcuate in the distal two-thirds, and presenting proxiraa> cephaloid by a broad constriction ; accessory pieces one-half to two-thirds as long as the spicula. This species has been found on roots of plants at Prankfort-ou-the-Maia and also Jena, Germany, and in Holland. 6. T. gracilis. De Man. -i^^y-^VM- »= + -«• Stria; of the cuticula exceedingly fine; neck diminishing but little; slightly hetero- cephalous, the head being short and rounded in front; spear stout and furnished with three large bulbs at the base; posterior margin of the median bulb at five per cent. ; posterior end of the oesophagus not distinctly seen ; jiorus cvcreforius opposite the posterior margin of the median bulb ; lateral markings on the head. — —^ 11 ( 2-1 mm. iJursa completely enveloping the conical posterior extremity, and presenting lateral papilhe a little behind the middle of the tail; the small plump spicula accompanied by short somewhat arcuate accessory pieces. Eare in forest and meadow ground, Holland. 7. T. lamelliferus, De Man. ? ] 'V %+ T ..n,m. Cuticula with exceedingly fine stria;; two lateral and four submedian wings throughout the length ; neck diminishing somewhat to the homocephalous, rounded anterior extremity ; lips and papillsc none ; spear long but slender, with distinct bulbs at the base; median oesophageal bulb large; 2W-us excretorius situated between the median bulb and the intestine ; terminus of the tail rounded. 3 ? 18'2 M oe;! T) ? T ? f9 ) '■"'"'• iiursa completely enveloping the posterior extremity, somewhat peculiarly narrowed in front of its posterior terminus, and presenting two lateral papilla; a little in front of the middle of the tail \ the stout spicula accompanied by rod-like arcuate accessory pieces. Eather common in moist ground, Holland. 8. T. pratensis, De Man. ^V— J— ^—",'^^^T- ■«■>"..• Neck diminishing but little to the somewhat heteroeephalous discoid anterior extremity, which presents two lateral chitinous markings ; lips and papilho none' spear very stout; median bulb nearly spherical, the posterior swelling pocket-shaped; porus excretorius at sixteen per cent.; lateral fields one- Iburth as wide of the body. B 172 Agricultural Gazcflc. Two papillffi near the end of the bursa ; the slightly arcuate spicula, aceompaiiied by short arcuate accessory ])iece8. A slow-amoving species found in meadows and marshy ground in Holland. 9. T. obtusus, Bastian. -l- \ V ' "U '11 ■'^"""- Cuticula present- in" about seven hundred transverse striiB ; conoid neck tcrmmatiug in a truncate head ; lips and papillte none ; spear stout and bulbed ; ellipsoidal median bulb situated at ten per cent., one-half as wide as the adjacent part of the neck ; cardiac collum distinct ; the granular intestine terminating posteriorly in a rectum whose length is equal to that of the anal diameter ; porus excretorius at fourteen per cent. »i — I — '^l' ^^ °y . -TTmra. Tall couves conoid ; bursa beginning opposite the prosimse of the oblong, somewhat arcuate spicula, which are as long as the anal diameter and accompanied by accessory pieces half as long.* Roots of oats, England. 10. T. terricola, Bastian. ': ; T T To " »'"■•. Conoid neck ter- minating in a truncate head ; ellipsoidal median bulb situated at about ten percent.; posterior swelling none (?) ; porus excrclorius at twelve per cent. Male unknown. Rootlets of wheat, England. 11. T. imperfectus, Biitschli. >„ ] T t — nr >''.™>- Spear bulbed ; lateral fields fiuely granular ; tail conical from the vulva ; uterus short, mostly with one egg, and that segmenting ; oviparous ; mature when only eight-tenths of a millimetre long. ij— I — ^y^ — =^7 — %■ Considerably smaller than the female ; spear a mere point ; tail concave-conoid, the large and wide bursa extending even a little beyond the end of the tail and far enough forward to be symmetrically arranged with respect to the anus ; ribs none (?) ; spicula twice as long as the anal diameter and bent in the middle, the proximal halves being twice as wide as the distal halves ; proximae cephaloid by a broad constriction ; accessory pieces none. Decaying fungi, Erankfort-on-the-Maiu, Germany. Related to number 12. 12. T. fungorum, Biitschli. i'."?! °'a 1"t'(i-6, "li; I'e S"""' Cuticula present- ing about fifteen hundred transverse striae ; conoid neck terminating in a truncated head, which is probably lipless and devoid of papilla); oesopluigus indistinct and without bulbs (?) ; cells of the intestine with a few large granules ; rectum nearly equalling the aual diameter in length ; lateral fields two-fifths as wide as the body, the dorsal field narrow ; uterus nearly half as long as the body and containing many spherical or ellipsoidal unsegmented eggs each two-thirds as long as the body is wide. '. '> '. " '";* ■■"■""'• Tail conical, hooked in the larv.-e ; more than halif of the bursa in front of the anus ; a double ventral post-anal papilla opposite the middle of the accessory pieces, and a single one opposite their ends ; the straight spicula somewhat dumb-bell shaped, and a little longer than the anal diameter; the forked accessory pieces as long as the spicula, extending backwards and terminating in extremities turned ventralwards. Found in decaying fungi, Erankfort-on-the-Main, Germany. • Bastiaii's text and figures disagree with regard to the length of the oBSophagus of this species. Jfew South Wales. 173 13. T. BCandens, Schneider, i' I ?-^c,T ° I^3-»3mm. Somewhat spirally curved ; cuticula with two thousand five hundred striae ; spear with three bulbs at the base ; median bulb at one and eight-tenths per cent. ; porus excretoriiis at three and one-tenth per cent. ; lateral fields one thirtieth as wide as the body. T — j — J — ^ — yY^-3m«>. Straight ; spicula one-third as wide as long, shorter than the anal diameter ; the accessory pieces one-third as long and much more slender. (Syn., T. trilici, Bast., Aiiguillula tritici, Needh.) The young or larvoB, to the number of eight or ten, arc found in so-called "gouty" wheat-grains. The portion of the grain usually occupied by the embryo becomes in consequence powdery and incapable of germi- nating. When the wheat is sown the larvic bore their way through the weakened wall of the diseased grain and pass out into the soil, where they attack and enter sprouting wheat grains. Here they remain for a time — perhaps the whole winter through — without change. When the wheat starts on its spring growth the larva5 make their way into the flower-bud, become mature, copulate, and after producing a new clutch of egi,'s, die. The eggs hatch, and the resulting larvas penetrate the new wheat-gi-ains, and soon become their only contents, the above-mentioned powder excepted. If infested wheat be stored, even for many years, the larva? still remain alive, ready to make their way out of the grains whenever the wheat is sown. The disease occurs in many parts of Euroj)e. Eemedy. — Inspect the grain, and reject all "gouty " seed-wheat. 14. T. devastatrix, Kiihu. i— ?— w Z "■' '-''^ ■""<■ Marked with about two hundred twenty transverse striae; the conoid neck terminates in a truncate head devoid of lips and papilte ; spear-bulbed at the base ; oesophagus one-sixth as wide as the neck ; median bulb small, the posterior large ; porus excrelorius lying near the median bulb ; intestine terminating in a rectum two-thirds as long as the anal diameter ; tail diminishing from the vulva, convex-conoid behind the anus; vulva prominent; rudimentary posterior branch of the sexual apparatus sac-like and extending half way to the anus ; eggs twice as long as wide ; viviparous or ovi-viviparous. \- — f — 'ra — "5— si '->•'>'»■». Tail conoid, diminishing more rapidly near the anus, sometimes constricted behind the middle, as is also that of the female ; bursa commonly springing from near the anus, devoid oi ribs somewhat variable; spicula cuneiform, slightly arcuate, less than half as long as the anal diameter ; arcuate accessory" pieces one-third as long as the spicula. (Syn., T. alUi, Beyerinck ; T. dipsaci, Kiihn ; T. Hyacinihi, Prilleux ; T. Raversteinii, Kiihn.) Found in many parts of Europe. There is reason to believe that it exists also in Australia. A most destructive parasite, attacking many varietiea of cultivated plants. It sometimes sweeps off the onion crop in Belgium. It attacks teasel, hyacinths, rye, oats, buck-wheat, potatoes, &c. It commonly prefers the flower and fruit, but may attack any part of the ])lant. In rye it causes " knots " or galls ; in potatoes it causes a disease similar in appearance to the potato-rot due to Po-onospora infestans. Kemedy.— Difficult to deal with. Can be starved out by keeping the laud free of vegetation of every description. It may probably be trapped like T. Scliachiii, though I do not know' of any cases' in which it has been 174 Agricultural Gazette. done. This worm is said to be killed by the digestion of domestic animals, so that manure could not be infected except by bits of bedding, &c., used in stalls. This worm is not injured by moderate desiccation. 15. T. velatus, Biitschli. Female unknown. ^ — , — , — ^^ fs ■''"■"'• The conical neck terminating in a head devoid of lips and papillas and appearing emarginate in optical section ; spear rather slender, bulbed at the base ; oesophagus seemingly devoid of bulbs ; poms excretorins at fourteen per cent. ; tail conical, almost completely enveloped by a bursa devoid of ribs ; spicula cuneiform, equalling the anal diameter in length; accessory pieces (?). Eoots of moss, rrankfort-on-tlie-Maiu, Germany. 16. T. leptosoma, Do Man. '?" ' 'f '"'» V "«■""■■ Strisc exceedingly fine : neck tapering much ; homocephalous, the head rounded in front ; lips and papilla; none; spear weak, bulbed; crsophagus distinct; median bulb ellipsoidal ; tail conical, the terminus setaceous. ';° • '7 ,"„ °f oomm. Tail like that of the female ; bursa extending but a short distance on each side of the anus ; spicula slender and devoid of accessory pieces. Very common in moist soil, Holland. 17. T. filiformis, Biitschli. »-jiL_|_l?l_il!L_™;i .55mm. Two hundred and fifty strife ; heterocephalous, the head being rather long, rounded in front, and devoid of lips and papillae ; spear bulbed ; median ceso])hageal bulb ellipsoidal, situated at one-third the distance from the mouth to the intes- tine ; cardiac bulb larger, and of about the same shape ; cardiac collum broad and indistinct ; cells of the intestine coarsely granular ; rectum longer than the anal diameter ; j)orus excrc/orins at twelve per cent. ; lateral wings distinct ; vulva inconspicuous ; rudimentary posterior branch of the sexual organs reaching one-fourth the distance to "the anus ; eggs as long as the body is wide and one-half as wide as long. . ';" I '»;3 M |_ .53 „m. Tail like that of the female; bursa like that of number 16 ; spicula slender, arcuate, and unaccompanied by accessory pieces. Fraukfort-on-the-Main, Germany, and in Holland ; common in the soil. 18. T. macrophallus, Do Man. --■ ? I T "L V •^'"""- Cuticular finely striated ; neck tapering but little ; homocephalous, the head being truncate in front and devoid of lips and papillm ; spear large and stout ; median bulb larger in the female than in the male ; posterior end of the oesophagus widened and pocket-shaped ; poms excretorins at twenty per cent. ; tail conical. -5;'_^2M_^i_j>M_ .^, ,„___ rp.,;! conical ; bursa like that of the two pre- ceding species ; spicula large, somewhat arcuate, acute, unusiially long, with short, rod-like arcuate accessory pieces. An active species, rare in fresh-water meadows, Holland. 19. T. pillulifer, A''on Linstow. w ; ":' ":, T ■"."■"■■ Neck conoid to the rather rounded head, which appears in optical section to be deeply emarginate; spear bulbed ; oesophagus cylindroiJ, over one-third as wide as the neck ; pioriis excretorins at twenty per cent. ; tail conical. J{ew South Wales. 175 ■39 ram Tail conical ; bursa nearly symHietrical with respect to the aims, ending postcrioi'Iy near tlic middle of the tail ; spicula one-fourth as long as the tail. "Water, Ratzeburg, Germany. 20. T. Davainii, Bastian. l;5-Jtl's e.vcrc/on'iis at eleven per cent. i — ♦ — i — 2T — f — "''"""■ J-ail conical; bursa springing from a little in front of the anus ; ribs and papilhe none ; spicula rather plump, accom- panied by weak, linear, arcuate accessory pieces one-third as long. An active species, found in fresh and brackish soil, Holland. 22. T. elegans, DeMan. -K'- ] "' ";, -f imm. striae of the cuticula exceedingly line; neck diminishing considerably to the barely heteroce- phalous hemispherical anterior extremity ; lips and papillsc none ; oesopha- gus with a rather small median bulb and a posterior widening; ^orvs cxcre- toriiis variable ; tail conical. T ! f — 2^0 — T" '■ """• Tail conical ; bursa small, symmetrically arranged •with respect to the anus; spicula slightly arcuate, with slightly arcuate accessory pieces one-third as long. (Syn. T. exiguvs, De Man.) Moist soil, Holland. Becomes sexually perfect when small. 176 AjricuXtwral Gazette. 23. T. Askanaseyi, Biitschli. 'X \ "^^^Z^ T' '""- Cuticula smooth (?) ; the fusiform body continued in front by a convex-conoid neck ; L'p rogion distinct; spear vvitha tiiree-bulbed base; oesophagus one-eighth to one-fiftli as wide as the neck, expanding to form a median bulb twice as wide; posterior bulb one-fourth as long as the oesophagus and half as wide as the adjacent part of the neck, and containing a cell ; cardiac coUum not very distinct ; cells of the yellowish-brown intestine filled with granules ; rectum twice as long as the anal diameter ; wings present ; tail conoid, its terminus pointed ; vulva prominent ; rudimentary posterior branch of the sexual apparatus extending more than half-way to the anus ; the unsegmented eggs as long as the body is wide and half as wide as long. K — \ — T8~~r — ^ '■'"""• Tail conoid from the inconspicuous anus; bursa apringing from opposite the proximse and extending to the middle of the tail; si)icula cuneiform, slightly arcuate, one and one-half times as long as the anal diameter and accompanied by linear accessory pieces one-third as long. Males and females equally abundant among the leaves of moss; Germany. One to two dozen adult worms are found among the leaves of a moss-bud, accompanied by countless young. The latter develop in the moss-bud until as large as the parent worms (1' x '028 mm), the sexual organs, however, remaining very rudimentary. 8exual maturity seems to be reached only after a residence in the soil, and when the young worms have made their v( ay into the buds of young moss-plants, and is then, as in T. fmiyornin, probably ' attained at a single moult. 21. T. mirabilis, Biitschli. \^\ V "f °L '•»■"• Cuticula striated; neck convex-conoid ; heteroeephalous, the head being about hemispherical; lips and papilhc indistinct ; spear slender, bulbed, hollow ; oesophagus in its anterior part one-third as wide as the neck, a little behind the middle becoming rather suddenly twice as wide ; cardiac collum not deep but distinct ; rectum one-third as long as the anal diameter ; tail convex- conoid to the rounded terminus ; vagina two-thirds as long as the body is wide, thick-walled ; ovary reflexed to near the vulva ; male unknown. Only one specimen has been seen. Eoots of moss, forest, Frankfort-on- the-Main, Germany. Note. — It is in order to place in the annals of Australian literature a connoctod a'ceount <}f Ihe important genus Tt/lenchus that I have inpcrled the foregoing summary, in which I include Ihe species hitherto referred to tlte genua Heterodera, inasmuch as I bclievo them to be in renlity species differing in no very es.sential manner from those constituting the group Tylcnchu.i. I venture to hope that with the aid thus afforded any one familiar with tlio \ise of the microscope will be able to recognize the different species of Ti/lencMis. Where there are so many capable microscopists it is reasonable to ho].e that some will now and then turn their attention to the exceedingly interesting and important group of animals of which Tt/lenc/ius is a member. It will be necessary to spend a few moments in mastering iho formula used. For this purpose the reader is referred to page 131 of the first number of this Gazette. For the convenience of those most familiar with the English unit of microscopic measurement it is deemed best to insert hero the following Sule. — To convert millimetres into inches, or thousandths of a Mjillimetro (/t) into thoueandlhs of an inch, multiply by '03937. Mew South Wales. Ill III. The Disease and its Remedies. WuAT is the exact nature of the disease caused by a root-inhabiting Tylenchus? How docs it spread from one plant to another, and from infected to non-infected lands ? Is there any cure or preveutive ? These are the questions to bo answered in the present section. In the two previous sections the subject has been dealt with rather after the manner of a scientific treatise. Such a course needs, however, no apology, for it will now be seen that all the remedies for, and precautions against, this root disease depend completely upon a scientiiic Itnowledge of the microscopic worm which is its sole cause. The nature of the disease caused by Tyhmchus arenarins will become clear as soon as the diseased tissues are carefully examined. Fig. 7 represents a portion of a diseased parsnip rootlet, considerably mag- . nified. The two swellings have been caused by, and ',1 contain, the gall-worms. Between the swellings the )^ rootlet retains its normal size and structure, except that \1^ r, some modification may occur through sympathy with the y ( diseased part. If a thin section of the undiseased part \ I be examined, it will bo found to present the usual struc- ture. Beneath the epidermis of the rootlet lie cells of a EootIet'of PiRsmp. constituting the hypoderm, and in the midst of these showing two gaiis due is found a single largo central vascular bundle surrounded to attack of gaii-worms ; by pericambium. The tissue of the central vascular '""^'i' bundle is made up of three portions, — the woody portion or xyloui, having in the section the contour of an hour-glass or dumb-bell ; the sieve tissue or phloem, appearing iu the section as two narrow crescent-shaped areas, lying between the two parts of the xylom and the surrounding pericam- bium ; the cambium occupying the remaining space, i.e., the two angles where the two xylom portions come into contact near the centre of the root- let. If now a section of the diseased part of the same rootlet be examined, it will be found that the additional size is caused by an increase in the amount of each tissue, but particularly of those constituting the vascular bundle. The epidermis and hypoderm remain comparatively unaltered in structure, but have increased somewhat in amount. The central vascular tissue, on the other hand, is much altered. It is increased in quantity, and the vessels have become much distorted. Instead of continuing parallel to the axis of the rootlet, as they would normally do, tlie vessels have become twisted about, and are often found turned to one side or the other, passing some- times in a radial direction, and even in some cases turning backward. Whatever portion of the tissue has been actually invaded by the worm is easily recognized by its yellow colour. In the majority of cases, according to my observations, it is the cambium of the rootlet that suffers the greatest destruction. The rootlets are the most fundamental organs of a land-plant. Upon them depends its 8up])ly of water and earthy material. Taking this fact into consideration, we shall no longer wonder after noting the changes wrought by the gall-worm, why so small an assailant can do so great injury. The plant is attacked at its weaicest point. The tissues of one of its most 178 Agricultural Gazette. essential sets of organs, the rootlets, become aborted. The absolutely essential food due the plant from the soil is cut off, and unable to live upon air alone it dies. Let us now turn to the disease as manifested in the potato. Pig. 8 repre- sents more or less spherical growths which appear in the substance of attacked potatoes. These growths seem always to bo connected with distorted vascular tissue. Tliey are found to vary much in size, and there seems little doubt that the " knobs," characteristic of the disease as it appears on the potato, are the result of these small beginnings. Each such body is composed of a thick outer wall, and an inner granular mass. These appearances in the parsnip and potato lead me to suspect that the abnormal growths caused by Ti/lcnchtis ... «/T««r«a« are probably to be compared to the galls produced (I, coll containing ' . .- - i ,, , o, J. . ,, starch grains ; b, on leaves by various insects. It is well known that ieatgalls secn"fn' attacked ^^'^ causod in the first place by a disturbance of the vascular potato; c, vesica- tissues. The gall-producing iusect commonly pierces a veiii lar tissues x 40. ^^ ^ j^^ j^^^l ^^,jj.j^ • ^^ o^jpoj^jto ^ ^,,1,^,1 depositing its egg. It is a common belief that the gall appears in consequence of a fluid injected by the insect at the time of laying the egg. I do not know whether this belief is supported by any good evidence. Possibly the mere irritation of such a foreign body as the egg of an insect or the wriggling larva hatched from it may be sufficient to account for the gro>vth of the gall. Certainly there are difficulties in explaining the growth caused by Tylcnclins on the theory of the irritation being caused by an excretion. The more natural explanation seems to be that the abnormal growths are the result of mechanical irritation. If I am right in comparing the swellings produced by Tylenchus arenarius to the leaf-galls produced by insects, then the former should be called root- galls, and the Tylenchus itself may appropriately bear the name of the gall- worm. Dr. Neal has called the disease, as it appears in the United States, the root-knot disease. His name can have no reference to knots, the places where branches originate, otherwise it would be entirely inappropriate, but refers to the characteristic appearance produced by the disease on rootlets, which has been compared to the appearance of a thread with knots tied in it. The German name for the disease caused by Tylencliiis Scliaclitii is Riibenmiidigkcit— that is, turnip-lassitute or beetroot-lassituto, referring to the tardy growth of the diseased plants. I believe both these names will be supplanted by the simple term "root-gall" (Wurzelgalle), which may be thus defined— abnormal growths on roots and rootlets, caused by the attacks of gall-worms. Historical. It is not until within recent years that ^\e have arrived at an accurate knowledge of the habits of the gall-worm, although the disease root-gall has been known for a very long time. How long root-gall has been recognized as a distinct disease of the sugar-beet of Europe 1 am unable to say, but that it is very many years is certain. The root-gall of the peach has, according to Dr. Neal's exceedingly useful pamphlet, been known to the white people of the South Atlantic and Gulf States of America since the earliest settlement of the country ; and, according to the same authority, reliable agriculturists state that the disease is indigenous there, they having seen it in places where neither trees nor jjlants had ever been introduced Meiv South Wales. 179 from other sections. The disease is now known to occur in North America on a belt of land 130 miles wide, extending from Texas along the Gulf of Mexico and Atlantic coast northward to the January isothermal of 50° Fah. According to the best testimony yet obtained, the peach tree Ibrmcrly grew on this area with no other disease than the borer, except in damp localities, while now in many places, owing to the prevalence of root-gall, the trees that do well are the exception. This fact shows how the disease has spread, or at least increased, and should serve as a warning to Australians. In tlie United States the plants that have been found to be attacked by Tylenchts arctiarms, the Australian worm, are as follows : — Badly effected. — Boots of cabbage, kale, potato, banana, radish, okra, pea, peanut, cow-pea, bean, squash, pumpkin, melon, cucumber, tomato, beet, plum, apricot, peach, almond, fig, English walnut, willow, gourd, bigonia, sunflower, amaranth, dahlia, koniga, iberis, coleus, achyranthes, purslane, sand-purslane, verbesina, worm- wood, Jerusalem-oak. SliglUli/ affected. — Roots of cotton, egg-jjlaut, pepper, spinach, cassava, maize, orange, grape, mulberry, walnut, pecan, hibiscus, ice-plant, parlor ivy, morning-glory, nolana, jjetunia, boussingaultia, spirea, flowering almond, buddloia, cape jessamine, shepherd's purse, blackberry, dewberry, eupatorium, cypress vine. These lists include the majority of the most useful food-plants, many ornamental plants, and a number of the commonest weeds. Among the latter, the roots of purslane, amaranth, Jerusalem-oak, and worm-wood, harbour the greatest number of worms. The extent of the damage done by gall-worms is diflBcult to estimate. Much land in Europe has become so badly infested that certain crops — for example, sugar-beet — have had to be abandoned altogether. Not a beet-root will mature. The plants break the ground, languish a few weeks, and then die. Since time immemorial, crops of various kinds have died suddenly — so suddenly, Dr. Neal remarks, as to justify the expression, "struck by lightning." The unknown cause in some such cases has probably been the gall-worm. Many an agricultural or horticultural failure attributed to the use of improper fertilizer, to poor soil, or wrong cultivation, has been due to this insidious foe attacking the very fountain-head of vegetation. "Were it possible to sum up in pounds, shillings, and pence the damage done either by T. arenarius or Scliachtii, the total would probably amount to a fortune for a nation. Bemedies. All that can be done in combating root-gall must be directed toward prevention. Once the gall-worm gains access to the roots, tlio game is up. A leaf-destroying pest may be dealt witli even after its attack has made some progress, but thus far, at least, roots and rootlets are inaccessible except at the expense of the life of the plant. Hence it follows that all rational remedies for root-gall must be directed either toward ridding the soil of the gall- worms, or toward putting such obstacles in their way, or so reducing their number, as to render their ravages bearable. These ends have been sought in various ways : — 1. By the use of some chemical, preferably a fertilizer, which will destroy the free-living larvai. 2. By the selection of varieties not subject to root-gall. 3. By trapping the worms and thus removing them mechanically from the soil. Agricultural Gazette. I shall consider the last of these methods first. 1. Trapping. — It consists in actually capturing the worms and then killing them by hand or by machinery. How to capture a foe numbering millions and doubly masked by being invisible and being hidden away underground might well seem a puzzling question. How it was answered constitutes one of the interesting passages in the history of applied science. The gall-worm of the sugar-beet had long been known to be one of the worst pests of that crop. " Various investigations were made and various remedies tried by those interested in the sugar-beet industry, but to little purpose. Year by year the pest grew wor.se, — more and more land had annually to be abandoned by the beet grower. At this point the pliilosophical faculty of the University at Leipzig oilered a prize for the best investigation of the cause of the Eiibenmiidigkeit. The prize was awarded to Struboll for an investigation whose results are detailed on page 170, under the head of T. scJiachtii. Professor Kiihn, making Strubell's investigations the basis of his reasoning, now devised a plan for trapping the larv». Noting that, according to Strubell's investigations, the larvtc on entering the young beet plant became mature in about live or six weeks, he predicted that if the plants were pulled at the end of four weelcs, the worms in them would die without producing a new brood. It will be seen that Professor Kiihn's plan was based on a careful perusal of the life-history of the Tylenchus. If the plant should be allowed to remain five weeks before being pulled, the worms would, it is true, be lulled, but not so the rggs which in five tveeks the females would have produced. These eggs would ultimately hatch and the pest continue. But after precisely four weeks, even the oldest worms in the roots would not yet have produced eggs, and, being at that time motionless sacs, in- capable of boring their way out, must perish from starvation if the host- plant should suddenly die. In other words, Kiihn proposed to make trapa of the young plants, and naturally chose such plants as are loved best by the worms. Sugar-beet was selected as the plant likelv to entrap tlie greatest numbers. The result of the experiments based upon Kiihn's plans was a brilliant one. A piece of ground, so badly infested as to be useless to the sugar-beet grower, was sown with sugar-beet. After four weeks the plants were pulled, and another lot of seed sown. The experiment was repeated a third time, if necessai-y, and it was then found that the post was controlled. The time occupied was about three months. Tlie plants whose roots were used as traps could be turned to account as fodder or fertilizer, so that the twelve weeks were not a dead loss. In Kiihn's first experiments the plants were pulled by hand. That operation was expensive, and led to a trial of ploughing up the trap-roots, and this plan was found to answer almost equally well. It is beforehand to be supposed that tlie Australian T. arenarius may be trapped in the same way as T. schachtii, but the time required for its develop- ment is not yet accurately known. As Consulting Pathologist to the Agricultural Department, it is understood that only my spare time is avail- able, and that has latterly been so -very meagre that since fir.st giving atten- tion lo this matter, one month since, I have found but three days in which to make it the subject of investigations. In consequence, I have no data for giving the precise length of time required for the larvio to mature in roots. The most I can say is that it is probably less than that required by the sugar- beet gall-worm. Consequently, in any trial of Kiihn's remedy in dealing with T. arenarius, it will be best, in the present state of our knowledge, to keep well within his limits and allow (say) three weeks before ploughing up Jfew South Wales. 181 the trap-roots. Mangels will make the best trap-root, and they should be sown thickly. 2. Oall-proof Varieties. — Dr. Ncal recommends, as a practically gall-proof stock for the orange, the hardy bitter-sweet or 60ur species, and, with some qualification, Citrus trifoliata, and the Japanese Unshin, or iSatsuma ; as a neai'ly gall-proof stock for the peacli, seedling American wild plum or one of the Japanese plums Kelsey, Satsuma, or Ogru ; as a stock for grapes perhaps the cordiJoUa or vtilpina races. Por other plants subject to root- gall he found no resistant stocks. Fire la a powerful destructive agent which may, in certain case."*, be brought into play in combating root-gall. Tlie larva; of the gail-worm infest the soil to a depth of at least 2 feet, but by far the greater number are found within a few inches of the surface. The heat of a large fire will penetrate to this depth in sufficient degree to destroy life. This fact may be applied iu setting out tliose trees particularly subject to root-gall, such as the peach, apricot, almond, plum, and fig. Nothing short of a large fire, lasting several hours, will kill the worms. The tree must be set in the midst of the burnt area, and no soil or fertilizer used except such as is known to be free from gall-worms. 3. Use of destructive c7tfi7«/c«/s.-*-K.\periment,s looking towards the use o£ some fertilizer or chemical destructive to gall-worms have been made, and the results may bo summed up as on the whole negative. No thorough- going chemical remedy for Eiibenmiidigkeifc has ever been discovered, although multitudes have been tried. Similar negative results were obtained by Dr. Ncal in the case of T. arenarius. Still the results are interesting, as pointing out what positively will not succeed ; furthermore, they may bo made the basis of plans for further trials. Of all the vermicides yet tried, lime receives the highest commendation. It must bo used iu large quantities to be effective. (The same is true of the muriates and sulphates of potash and ammonium.) One to two tons of lime to the acre, applied, not all at once, but part in Juno and the remainder in October or November, may be recommended. The result is the destruction of a large number of worms ; but many eggs, protected bythctissues in which they are being incubated, doubtless escape destruction, and live to propagate the disease. I have noticed that when the disease is combated with chemicals, the method has been in all eases drastic, the attempt being to kill all the worms at one fell swoop. Possibly a homoeopathic treatment would be more fatal. It is easy to believe that many of tlie experiments which have been tried were in reality effective so far as they went, although pronounced unsuccessful because the disease reappeared. My experiments have already shown that the period occupied by the development of the egg of T. arenarius may possibly extend over two months or more. While yet in the egg, the young worm is protected by the shell ; and this protection is a good one. The shells of nematode eggs (as well as tlie skin of the larva when it is being cast) are comparatively impenetrable. Poisons which would at other stages of life be fatal, can therefore be withstood by embryos and moulting larva;. I may support those statements, which are based on my own observations and experiments,* by the remark that the eggs develop in the very midst of decaying matter. The roots attacked by the disease die and decay, thus giving rise to chemicnls of considerable strength and acti^^ty. Yet the eggs develop unharmed — quite likely, on account of the impenetrability of their shells. Now, suppose in some of the numerous experiments that have • For instance, 1 have observed that spcrios which under ordinary circumst.incca are instantly l