TtaubenfQIII b. 61 nieDerl)ana

ON A NEW CLASSIFICATION OF THE BDELLOID ROTIFERA.

By DAVID BRYCE. (Read June 28th, 1910.) h has long been felt by those who are interested in the BDELLOID HOTIFERAthat a revision of the classification of this group would considerably facilitate further investigation into a comparatively little-known corner of the animal kingdom. During the last eighteen years the number of known species has more than doubled, the great majority of the new forms being additions to the two genera Philoclina and Cctlliclina, which have conse­ quently become overcro:wded, unwieldy, and unsatisfactory. Besides this, a more intimate acquaintance with the diversities of structure and of habit of a gr'eatly extended array of species has proved that not only are the old generic definitions in­ f.dequate, but that they are also unreliable, and should no longer be accepted. The object of this paper is to place the classification of the BDELLOIDAon a more satisfactory basis, and it is hoped that the arrangement now put forward will provide a sound foundation, or, at the least, a new starting-point for future work, and that the lines on which it is framed will prove to be reliable and true to the natural relationships of the species with which it deals. Fl'Om the point of view of classification the BDELLOIDROTIFERA have already experienced a somewhat complicated career. Their history as a recognised group of allied species seems to have begun in 1830, when Ehrenberg published his first Classified Li"t of Micro-organisms (2), wherein he introduced the family Zygot1"ocha, comprising all Rotifera with a ciliary wreath of two similar parts. So far as regards the BDELLOIDAthis earliest classification may be summarised thus:

FA~IILYZYGOTROCHA. Rotifera with corona of two similar parts (" ciliorum coronulis binis "). Loricate Section Bmchionaea. Illoricate Section Philodinaea. 62 D. BRYCEONA NEWCLASSIFICATIONm' THE BDELLOIDROTIFERA. D. BRYCEON A NEWCLASSIFICATIONOF THE BDELLOIDROTIFERA. 63

SECTIONPHILODINAEA. use of the number of spurs and of toes on the foot. It has been Without eyes . Gen. Calliclinct. pointed out by lVIurray in a recent p}1per (63) that the dis­ tinction made was inaccurate as between Rotife?' and Actin~t?'~ts, With two eyes. since the foot is not thrice furcate in the species assigned to Eyes frontal: Rotifm·. But if inaccurate in that case, the phrase" cauda ter Foot thrice furcate (" cauda ter fur- furcata" is conect with regard to the genus Philodh~a,and cata ") Gen. Rotifer. clearly indicates the two spurs, the two dorsal toes, and the Foot ending in two spurs and three two terminal toes posse' ed by all but one of the species which toes (" caudae quinque apicibus") Gen. Actinun~s. were described by Ehrenberg as members of that genus. Eyes dorsal: In 1884 Hudson (17) recognised the distinctive character of Foot simply furcate (" cauda sim- the manner of creeping peculiar to the group, and proposed pliciter furcata ") Gen. jJ£onolabis. that the several genera should form a separate order, that of Foot thrice furcate (" cauda ter fur- the BDEJ,LOIDA, or I,eech-like Creepers, and this proposal was cata") Gen. Philodina. further established by its adoption in 'l'he Rotife?'a, published by him in 1886 in collaboration with Gosse (19). In this work In the following year, 1831, Ehrenberg published a more the new family Adinetadae and the new genus Aclineta were comprehensive arrangement (3), in which the Philodinaea were created for the reception of a species which differed markedly advanced to the rank of a family, and this position was again in the type of the corona from all others of the group included assigned to them in his great work of 1838 (4), based upon his by them at that time. The four recognisable genera of Ehren­ third and best-known system of classification. In these later bel'g were placed in the new family Philoclinadae, and were schemes the two genera Typhlinct and Hyclrias were added to distinguished as before by the presence and position of the eyes. the Family with the following characters: Earlier in the same year, 1886, the importance given by vVithout rostrum or spurs: Ehrenberg to the eyes in the generic distinction of the Philodinaea Trochal discs on pedicels Gen. Hyclrias. had bpen challenged by Milne (18), who proposed to arrange Trochal discs without pedicels Gen. l'yphlina. the various species into genera either new or redefined, and to It bas not yet been found possible to recognise any of the discard altogether all generic characters relating in any way species assigned to the genei'a jJ£onolabis, Hyd?'ias, and l'yphlinct, to the eyes. He claimed for his scheme that it did not dis­ and these genera have not been accepted by later writers, who sociate manifestly similar forms, at least as regards some nineteen believe them to have been founded on imperfect observations species examined by him. His most valuable suggestion in this of animals which, if again seen, have been referred to other raper was that the genus Philodina should be distinguished by groups of the Rotifera. The four genera, Callidina, Philoclina, the possession of four toes, thus giving first place to the character Rotifm', and Actimwus, have fortunately proved to be recognis­ which Ehrenberg had indicated in 1830 in the phrase "cauda able, and the majority of the species, which have been discovered ter furcata." since 1838, have been assigned to one or other of them. In 1888 Milne (23) adduced fresh instance; in support of his As in the classification of 1830, so in his later schemes, previous contention, and proposed further that the genus Rotife?' Ehrenberg distinguished the four genera last named principally should be distinguished by the character" viviparous." upon characters afforded by the presence or abseoce of eyes, and, Another important advance was made in 1889, when Plate when present, by their position, either in the front of the head (27) pointed out that the Bdelloilla shared with the Seisonidae or in the neck. As a quite subsidiary character, to distinguish the peeuliarity of having two ovaries, whereas all other Rotifera Rotife?' from Actim~rus,and Pkilodinct from illonolabis, he made have one only. He proposed therefore to divide the class RO'l'Il'ERA 64 D. BRYCEONA NEWCLASSIFICATIONOF THE BDELLOIDROTIFERA. D. nRYCEONA NEWCLASSIFICATIONOF THE BDELLOIDRO'l'JFERA. 65 into two sub-classes, the DIGONONTA(or two-ovaried), comprising In 1905 James Murray (55) announced the discovery of the MONOGONONTA the Bdelloida and the Seisonidae, and the (or one­ curious Bdelloid, Jlfic7'oclinc£ IJC£7'acloxct,for which he created the ovaried), including all other Rotifera. new family .Afic'l'odinadc~e.This and numerous other discoveries In a useful monograph on the Philoclinaec£, published in 1893, of Bdelloid forms hitherto unknown, and in all cases communi­ J anson (38) discussed at some length the views and suggestions cated to me before publication, led naturally to the discussion in of earlier writers and, in particular, those of Hudson and Gosse, our correspondence of the demerits of the current classification of and of Milne. On the one hand, he criticised the creation by the the group. The arrangement of the genera and species now ad­ former authors of the family of the Aclinetadae. On the other, vanced is in great measure the outcome of that discus,ion. To he admitted the contention of Milne that under the definition of some extent the lines on which it is mainly framed have been Ehrenberg many eyeless species would be classed as Callidinae, indicated by my correspondent in recent papers, notably in (56) although in respect of their structure they should clearly be "The Bdelloid Rotifera of the Forth Al'ea" (1905) and in (63) regarded as belonging to the genus Rotife?" Nevertheless he " Philodinc£ mc£crostylc£ and its Allies" (1908). hesitated to accept the genera proposed by Milne, and preferred In the fOl'mer of these he provision'tl1y redefined the genera fol' the time to abide by the Ehrenbergian family of Philod'inaea, Philodina, Calliclina, and Rotife7' as follows: which in his view covered all the various genera. He made the PJIILODINA.-Having four toes and a corona consisting mainly one correction of transferring to the genus Rotife7' the two species of a pair of wheel-like ciliated discs. which had been assigned to Actimwt~s,recent discoveries having shown the differences between these two genera to be less definite A. Eyes present; ovip~rous. than had previously appeared. B. Eyes absent; oviparous. In an important treatise publisMd in 1899 Wesenberg Lund O. Viviparous; eyes present or absent. (50) dealt in great detail with the wide question of the l'elation­ OALLlDTNA.-Having three toes or a perforate disc formed by ship to each other of all the various groups of the Rotifera, and, a union of the toes; oviparous; eyes present or absent. in conclusion, put forward a new classification based largely upon A. Food moulded into pellets. results afforded by his own investigations. At the outset he B. Toes bearing a number of cup-like suckers, or united followed Plate in dividing the class ROTIFERAinto the sub-classes to form a broad disc. MONOGONONTAand DIGONONTAaccording to the number of ovaries O. Toes three; distinct, food not moulded into pellets. possessed by each species. So far as regards the MONOGONONTA, RO'l'TFER.-Viviparous; toes three. the subsequ!\nt grouping of the families and genera was carried out on principles essentially different from those of Hudson and In the latter paper he discusses exclusively the genus Philoclinc£, Gosse. The DIGONONTA,on the other hand, were little affected which he redefines as distinguished by: by the investigations of the author, according to whom this sub­ Four toes, eyes cervical or none; class included the two orders BDELLOIDAand SEISONACEA,the latter and subdivides into five groups of species: created to receive the family of the Seisonidae. \Vhile accepting I. Oviparous. from Hudson the order of the BDELLOIDA, Wesenberg Lund n. Semiloricated. followed J anson in placing all the Bdelloid genera in one family, In. Parasitic. Philodinidae, and in rejecting the genus Actinurt~s.The family IV. Short-spurred. Philoclinidae of vVesenberg Lund would thus be equivalent to V. Viviparous. Ehrenberg's family Philoclinaea, and according to the author During the period covered by the foregoing retrospect the included the five genera Rotifm', Philodina, Calliclina, DiscoptlS, number of species known to belong to the Bdelloid group has and Aclineta. very considerably increased. In Ehrenberg's _ classification of 66 D. BRYCEONA NEWCLASSIFICATIONOF THE BDELLOIDROTIFERA. D. BRYCEONA NEWCLASSIFICATIONOF THE BDELLOIDRO'l'IFERA. 67

1830 there are enumerated nine species, of which one, at least, a whole series of structural developments, and distinguishes the , has not been recognised since. The present arrangement deals Philodinidae, not only from the Adinetidae, but from all other with a total of 105 species considered to be capable of recogni­ members of the cln.ss ROTIFERA. tion, in addition to which some 49 species have been placed in a The Jl£iC1'odinidae are even more feebly equipped than the separate list as either insufficiently described or otherwise invalid. Adinetidc6e. The corona is practically absent, and the animals These" doubtful" species are not necessarily hopeless. Before can only creep about in a slow and clumsy manner by means of the lists are again revised, further observations may well have the rostrum and foot. They have some little compensation in provided sufficient reason for reinstating some of them among the being able to partly protrude their jaws from the buccal opening. species considered good. It is hoped that the discovery of forms allied to the single species I do not desire to offer any remarks upon the position to be yet known will provide further indications of its affinities with assigned to the BDELLOIDAamong other Rotifera. Although it other Bdelloida, but meanwhile I agree with Mnrray that would now seem that the BDELLOIDAdo not stand quite so far M. pcwadoxa is well placed in a genus and a family of its own. from the others as was formerly believed, yet the interval which The recently discovered and very remarkable species to which separates them appears still to be a wide one. It is sufficient to De Beauchamp (65) has given the specific name" inte1'media" accept the position assigned to them by Plate and Weseuberg shows a distinct advance in the direction of MiC'}"odina in the Lund and to regard them as an order of the sub-class DIGONONTA, structure of the mastax, in its adaptation to prehensory move­ distinguished from the SEISONACEAby their ramate jaws, their ments, and in the absence of any throat. But it possesses a fully more or less effective rostrum, the telescopic retractability of developed rostrum, and a corona which, although differing in their distal segments, and their contractile cloaca. important details from that which is typical of the Philodinidae, To the order of the BDELLOIDAI assign the three families, is nevertheless retractile at will within the mouth, and the species PHILODINIDAE, ADINE'l'IDAE,and MICRODINIDAE. In my opinion therefore comes well within the limits of that family as indicated both Janson and Wesenberg Lund, in rejecting the family in the definition following. Adineu6dae of Hudson and Gosse, have failed to appreciate the The family MICRODINlDAE,distinguished by the presence of a physiological difference, which is so intimately connected with rostrum and the absence of a corona, consists; therefore of the the structural distinctions between the Adinetidae and the single genus MICRODINA,represented by one species. Philodinidae. The former family, while possessing certain minor The family ADINE'l'IDAE, having an imperfect or retrograde capacities which are not shared with the latter, falls nevertheless rostrum, and a corona which cannot be retracted within the far behind in structural development and in funct.ional equipment. mouth, comprises the two genera ADINETA and BRADYSCELA,the It need only be pointed out that the Adinetidae are practically latter created to receive the species "clal6dc6," which differs very unable to swim and that their locomotive abilities are limited to notably from the Adinetc6 type in the structure of the foot. creeping about by means of their corona, aided by the foot. The The family of the PHILODINIDAE includes all Bdelloids with Philodinidae, on the other hand, can all swim in a more or less well-developed rostrum and corona, the latter always capable of vigorous manner. They can also creep about in leech-like retraction within the mouth. With the exception of the four fashion by the alternate use of the tip of the rostrum and of the forms placed in the new genera CERATOTROCHA,SCEPANOTROCHA, foot. But what in my view is most important, is that this and ABROCHTHA,the numerous species conform in most respects creeping about is not in any degree dependent upon the use of very closely to one strnctural plan. the corona. That delicate organ is for the time hidden away Of the few deviations from uniformity of plan, I regard as of within the mouth and so secured from possible injury. This great importance that which is found in the structure of the power of withdrawal of the corona without absolute prejudice to stomach of certain species. Although not hitherto employed or the power of locomotion is associated with and consequent upon suggested as a means of generic distinction, it has not quite 68 D. BRYCEONA NEWCLASSIFICATIONOF THE BDELLOIDROTIFERA. D. BRYCEONA NEWCLASSIFIOATIONOF THE BDELLOIDROTIFERA. 69 escaped observation, as may be judged from Ehrenberg's figure the lumen tube-like, but the outer membrane is not conspicuously of the stomach of Philodina collcwis (4), and from his description of much greater capacity. of that organ both in that species and in his Callid1:ncb ?·ediviva. To Section A belong the three new genera, HABROTROCHA, Gosse, in his turn, observed some peculiarities itbout the stomach CERATOTROCHA,and SCEPANOTROCHA. In the first-named the of Callidina bidens (19) which he did not rightly interpret. corona conforms with relatively minor modifications to the type Lastly, Milne (18) in his descriptions of species discovered by him usual in the family. In CERATOTROCHAthat portion of the skin drew attention in several cases to the remarkable habit of whch supports the upper lip and the lateral cushions of the moulding the food into pellets, which is universal amongst species mouth is produced into two horn-like processes upon whose whose stomach-structure deviates from the customary form in lower or ventral surface are inset the ciliated discs, the pedicels the manner now to be pointed out. which usually support the latter being either rudimentary or Briefly stated, the distinction made consists in the proportion absent. In SCEPANOTROCHAthe upper lip itself is modified into of the cavity of the inner or lining membrane of the stomach a membranous hood-like expansion larger than the corona, which to the cavity of the outer or enclosing membrane, and it is it completely covers (save the extremities of the cilia), and which constantly associated with a difference in the method of digestion it dorsally screens. and with other structural differences, which, if not of great value These three genera claim about one-fourth of the species of the in themselves, indicate clearly enough thitt the difference in the PHILODINIDAE. In my opinion they are representative of an stomach-structure is one that goes a long way back in the earlier stage in the development of the typical Philodine, the evolution of the Bdelloida. Making use of this distinction I have genera of Section B representing, broadly speaking, a distinct divided the genera of the PHILODINIDAEinto two Sections: advance in development, shown by thei1' g1'eater ave1'age size, the g?'eate1' P?·opO?·tional development of the CO?'ona,especially of the A. Lumen of stomach relatively wide, or bag-like; food t?'oc1wl discs, and thei?' g?'eater activity, mobility, and boldness. usually in pellets; upper lip usually entire; oviparous. The genera of Section B, comprising all PHILODINIDAEin which B. Lumen of stomach relatively narrow, or tube-like; food the lumen is tube-like, divide naturally into three Subsections: particles free, never agglutinated into pellets; upper lip usually bilobed or divided; oviparous or viviparous. 1. 'With four toes (two dorsal, two terminal). Il. With three toes (one dorsal, two terminal). In the genera of Section B the inner tube is very much Ill. With toes bearing a number of cup-like suckers, or united narrower than the outer, the interspace being occupied by a finely to form a broad disc, or twin discs. granulated digestive fluid, having 'a frequent admixture of fat­ particles. In the genera of Section A the inner tube is almost as St.bsection I., with four toes (the dorsal pair usually somewhat wide as the outer, and the granulated fluid is usually scanty or distant from the terminal).-In this subsection the remarkable apparently absent. Again, when the lumen is tube·like one foot of the Bdelloid rotifer attains its highest development. The frequently finds ciliary action visible either in the stomach or in comparati\'ely wide separation of the two pairs of toes, the the intestine. In my experience such action is never seen when the . independent action of each pair, their consequent control by lumen is relatively wide. The moulding of the food into pellets, different muscles and nerves, the rapidity and certainty of their which is universal among the species of Section A, hits never affixment, indicate greater specialisation than is exhibited by any been detected in any species with a relatively narrow lumen. other groups, however closely approached by individual forms. It is not to be expected that among so many species all In the same way, the four-toed species surpass their relatives should conform with equal fidelity to the distinction made in the development of the corona. The average width of the between the relatively narrow and the relatively wide lumen of trochal discs, in some species extremely ample, and its proportion the stomach. Notably in the genus Rotifm' many species have 10 the body-length are much in excess of those seen in other 70 D. BRYCEONA NEWCLASSIFICATIONOF THE BDELLOIDROTIFERA. D. BRYCEONA NEWCLASSH'ICATIONOF 'l'HE BDELLOIDIWTIFERA. 71

Philodinidae. In my opinion these details form good indices to the species now assigned to it have of late years seemed to me to the functional perfection of the food-collecting organ. represent the central group of the very heterogeneous crowd of The four-toed species constitute about one-third of the PHILO­ forms which the too elementary definition of "no eyes" has DINIDAE in the present list. I have divided them among five caused to be associated with this name. For reasons which will genera, of which three correspond to groups suggested by Murray be later explained I am far from satisfied that the identity as already quoted, viz. the" parasitic," the" viviparous and long­ of Ehrenberg's Callidincb elegcvn.s, the species for which he created spurred," and the "semi-Ioricate" groups. For these I propose the the genus Callidincb, has been rightly detet:mined by any of the new genera E~IBATA,DISSOTROCHA,and PLEURETRArespectively. authors who have hitherto accepted it, nor, although particularly For the present I hesitate to separate the "short-spurred anxious to establish as many as possible of the old but too species" (of Murray) from the "oviparous." Together they scantily described forms, have I myself succeeded in finding it. form a fairly compact genus, which includes nearly all the As to his next described species, Callidina j'ediviva, which would species assigned by Ehrenberg to the genus PHILODINA,and for seem to be a pellet-making form, I am in the same position. Of which I therefore retain that generic name. In these four six other species described by him after a long interval, three genera the corona is always in close conformity with the family are now recognisable, but belong to two very distinct groups, type, and in every case there is a distinct throat or passage (C.) alpi1b1n having foul' toes, and (C.) scarlcbtina and (C.) tetmodon to the mastax. In the recently described (P.) inte1'rnedia, having the foot ending in a sucker-like disc. Under these de Beauchamp, the corona differs from the type in several details circumstances I have felt myself at liberty to employ the familiar (most notably in the partial absence of the cingulum or secondary name for those species which remain in the old genus after wreath), and there is practically no throat, the mastax being relieving it of the most aberrant forms. The new definition is placed so closely below the mouth that the jaws themselves can perhaps somewhat too comprehensive still. The genus includes be employed in seizing the food. For generic distinction the three rather distinct groups of species which may be characterised latter character appears to me to be the most suitable, and I respectively as : propose therefore to refer to it in creating for this remarkable 1. Rough-skinned. species the new genus ABROCHTHA. 2. Smooth-skinned, short-footed, non-parasitic. S1bbsection 11., with three toes (the dorsal toe usually close to the 3. Smoot,h-skinned, long-footed, and parasitic. terminal pair).-The species with three more 01; less well-developed toes are divided according to their customary course of reproduc­ For the rough-skinned and the parasitic groups I think it will tion. For those which are viviparous I have retained the generic ultimately be desirable to provide separate genera. The second name ROTIFER as suggested by Milne (23). This emendation of group of smooth-skinned, short-footed, non-parasitic forms I the distinctive character makes little change in the constituent regard as generally representing the type of the genus CALLIDINA. species. With the exception of the discordant form "roepej'i," Subsection 111., with toes bearing cup-like suckers or united to now transferred to the genus HABRO'l'ROCHA,all the species with form a broad disc or twin discs.-Although the species included rostral eyes are viviparous, and therefore remain in the genus in this subsection are relatively few in number, certain of them with which they have been hitherto associated, whilst to their have been more exhaustively studied than all the other Bdelloida number is added the blind but closely related species" longirostris" together. The majority are large forms, possessed of well-developed J anson, and" magnicalcarata " Parsons. For those other three­ coronae, and they usually inhabit ground-mosses and liverworts toed species which are oviparous I retain the generic name of various kinds. But besides the moss-dwelling forms there are CALLIDINA,not because the genus as now presented contains any two species which are parasitic in habit and very distinct in some of the eight species described by Ehrenberg, who created the structural details, viz. DiscOP1bSsynaptae Zelinka, and A n01nopus genus (for the opposite is the case), but because the majority of telplmsae Piovanelli. The genera DISCOPUS and ANOMOPUSare D. BRYCEONA NEWCr,ASSIFICATIONOF THE BDELLOIDROTIFERA. 73 72 D. BRYCEONA NEWCLASSIFICATIONOF THE BDELLOIDROTIFE·RA. distinguished from each other by the arrangement of the foot­ glands, which in DISCOPUSare placed in transverse series, but in ANOMOPUSin longitudinal sel-ies as in all other Bdelloicla. SYNOPSIS OF THE FAMILIES, GENERA, :For the moss-dwelling species I propose the new genus MNIOBIA, AND SPECIES. distinguishing it from DISCOPUS by the longitudinal arrange­ Farn. ADINETIDAE BRADYSCELAgen. noy. ment of the foot-glands, and from the long-footed ANOMOPUSby ADINETAHudson and Gosse. the relatively short foot. OERATOTROCHAgen. noY. The order in which these families and genera should be SCEPANO'l'ROCHAgen. noy. HABltO'l'ROCHAgen. noy. placed is more difficult to determine. as I is than If, think OALLIDINAEhr. the Cftse, the pellet-making species are nearest to the primitive ROTIFERSchrank. Bdelloid type, the genera HABRo'l'ROCHA, SCEPANOTROCHA,and ORDER DISSOTROCRAgen. novo OERATOTROCHAmay be taken as representing the central line of BDELLOIDA PRILODINIDAE PLEURE'l'RAgen. noy. EMBATAgen. noy. growth from which at one period or another other groups have PHILODINAEhr. branched off, in most cases to subdivide again. If, however, the ABROCH'l'HAgen. novo functional development of the vftrious genera-that is to say, their DISCOPUSZel. capacities for gathering food, for locomotion, their general activity ANOMOPUSPiov. MNIOBIAgen. novo and endurance-be considered, then I think the genus PHILODINA MICRODINIDAE ]\i[ICRODINAMurray. should stand first, yet be closely approftched by ROTIFER and OALLIDINA,while at the foot of the list should appear MICRoDINA and BltADYSCELA,with OERATOTROCHAbut little above them. BDELLOIDA, But it is impossible in the mere sequence of genera and species An Order of the Sub-class DIGONONTAPlate 27 to give any adequate idea of both the relationships and the comparative development of the several groups which the genera (Rotifera with two Ovaries). are intended to represent. For the sequence of genera which ROTIFERA, with spindle-shaped, maggot-like bodies of numerous after various rearrungements I have finally adopted I make segments, those of the anterior and posterior extremities tele­ no claim save that of convenience. scopically retractile within those of the central body; hftving The new genus SCEPANOTROCHAis represented only by two ramate jaws, a more or less developed rostrum, and a con­ species new to science, and descriptions of these accompanied tractile cloaca. Males unknown. by figures follow after the general classification. The list' of species regarded as insufficiently described or I. FAMILY Adinetidae. otherwise invalid is supplemented by remarks on certain of the species included therein. Bdelloids, with usually imperfect non-revertile rostrum. I conclude this paper with a list of works dealing with earlier Oorona consisting of a prone surface clothed with short cilia classifications of the BDELLOIDA,or containing original or supple­ (which create no vortices), and non-retractile within mouth. mentary descriptions of species, so far as I am acquainted with Two genera. them. Throughout the text reference is made to these works Bradyscela gen. novo by numbers enclosed in bmckets after the author's name. (In the event of any described species or work having been Foot stout, with three toes, spurs modified or absent. omitted from the respective lists I shall be grateful if the B. clauda (Brj'ce) 36. fact be made known to me.) 74 D. nRYCEONA NEWCLASSIFICATIONOFTHE BDELLOIDROTIFERA. D, BRYCEONA NEWCLASSIFICATIONOF TI-IEBDELLOIDROTIFERA. 75

Adineta Hudson and Gosse 19. b. Pedicels more or less developed. Habrotrocha gen. novo Foot slender, with two spurs and three toes. Corona of family type without horn-like processes or hood-like A. vetget (Davis) 15. A. tttbe?'culosct J anson 38, expansions. A. oculata (Milne) 18. A. ba.?·batetJ [WROn 38. A. longic01'nis Murray 59. A. g?'ewilis J anson 38. H. angusticollis (MUI'my) 55. H nclusa (Milne) 23. A. gmndis Murray 66. var. attenuatet (Murray) 59. H bidens (Gosse) 8, 19. H longiceps (Murray) 58. If. t?'iptts (Murray) 60. H. pe?jm'atet (MUlTay) 59. H. t?'idens (Milne) 18. var. americanet (Mm'ray) 60. H lata (Bryce) 33, n. FAMILY Philodinidae. H pusilla (Bryce) 37. H. angulet?'is (Murray) 66. var. textrix (Bryce) 44. H. pulch?'a (Murray) 55. Bdelloids with fully developed rostrum, usually rever'tile. H. collcw'is (Ehrenberg) 3, 4. H. const1'ictet (Dujardin) 6. Corona of two functionally distinct wreaths of cilia; the H. e?'emita (Bryce) 41. H miC?'ocephalet (Murray) 56. trochus, dorsally and ventrally interrupted, passing nearly H. elegems (Milne) 18. If. mintttet (Murray) 61. round the peripheries of two elevated discs, and creating twin H. annulatet (MUlTay) 55. H. etspem (BI')'ce) 33. vortices; the cingulum, dorsally interrupted, passing from If. leitgebii (Zelinka) 20, H C?'enata (Murray) 55. behind the pedicels round their bases, and thence round inferior H. roeperi (Milne) 23, var. nodosa (Murray) 59. margin of mouth. Corona retractile within mouth. ./1-:r~~ I'h...,~ l.{J Thirteen genera. (

B. "r...umen of stomach relatively narrow or tube-like. Food never agglutinated into pellets. Upper lip usually bilobed .A. Lumen of stomach relatively wide or bag-like. Food usually or divided. Oviparous or viviparous. agglutinated into pellets. Upper lip asnally undividul. Oviparous. a. Foot ending in three toes.

a. Pedicels rudimentary or absent. Callidina Ehrenberg 2. Oviparous. Ceratotrocha gen. novo C. aculeata (Milne) 18. C. habita Bryce 41. 2~ a.fusc.a BrYGe-41. var. bulletta Mmray 58, Trochal discs inset between or beneath two fleshy processes C. 'Tnu1'icata Murray 55. resembling horns. C. angttStct Bryce 41. C. multispinosa (Thompson) 34. C. C?·twicomis Murray 55. C. c01'nigem (Bryce) 37. var. bnvispinoset Murray 64. C. natans Murray 58. var. C?"('/'ssispinosaMurray 60. C. pliccttet Bryce 33. var.zickendmhti Richters 67. Scepanotrocha gen. novo var. hi?'undinella Murray 61. C. pinnige?'a Murray 64. C. 'TIWscttlosa (Milne) 18. Trochal discs inset beneath wide hood-like membranous ex­ , C. pCtpillosa (Thompson) 34. C. elwenbm'gii J an80n 38. pansion of upper lip. C. quad?'icomijem (Milne) 18, C. ccmcrophilet Piovanelli 53. C. ves'icula1'is Murray 57. C. bmnchicola Nemec 43. S. ?'ubra sp. novo I S. c01'niculata sp. novo C. f01'nwSet Murray 59. C. speciosa Murray 60. 76 D. BRYCE ON A NEW CLASSIFICATION OF THE BDELLOiD ROTIFERA. D. BRYCE ON A NEW CL,\SSIFICATION OF THE BDELLOID ROTIFERA. 77

Rotifer Schrank 1 Philodina Ehrenberg 2.

Viviparous. Spurs usually short and without heel j animals wandering and in habit. Mostly oviparous, rarely viviparous. R. longi1'ost1'is (J anson) 38. R. vulga1'is Schrank 1. hee

var.ji;Jnb1·iata Murray 59. R. 'I1U6C1'U1·~tSSchrank 1. P. 1'oseolct Ehrenberg 3. P. nemomlis Bryce 54.

var. bit01'q~tCttc~Murray 64. R. ovat~~s(Anderson) 30. P. el'yth1'ophthalma Ehrenberg 2. P. l'~tgosaBryce 54. R. ta?'digmd~~Ehren berg 2, 3. • R. neptunius Milne 18. P. jlcwiceps Bryce 58. var. callosa Bryce 54.

R. elongat~tsvYeber 26. R. actinw·~tsJ anson 38 P. vomx (Janson) 38. var. COl'i(~ceaBryce 54.

R. t1'isecat~tSWeber 26. ( = Actin. neptuni~tsEhI'. 2, 3). P. citl'ina Ehrenberg 2, 3. P. plena (Bryce) 41.

R. spicat~~Murray 51. R. 1nctgnicalcamtc~(Parsons) 32 P. acutic01'nis Murray 51. P. sq~~a1nosaMurray 59. R. mento Anderson 30. (= ? Callidina socialis J anson P, megalot1'och(~Ehrenberg 3. P, g1'egal'ia Murray 66. R. cit1'inus Ehrenber} 4. 38). P. indica Murray 59. P. antctrctica Murray 66. o' _71'rn«~Y"()ceY,,$'.y~ P. conve1'gens MUI'I'ay 61. P. c~lat(£Murray 66. b. Foot ending in four toes. P. bl'evipes Murray 51. * With distinct throat. ** Without throat. -r Skin coarse and leathery. Abrochtha gen. novo Dissotrocha gen. novo Gullet absent. Rami immediately below mouth-cavity and Viviparous; abdominal transverse skinfolds few and con'e­ protrusible thereinto. sponding to segment boundaries. A. intel'media (de Beauchamp) 65. D. spi1wsa (Bryce) 33. D. mac1'ostyla (Ehrenberg) 4 c. Foot ending in sucker-like disc or twin discs. D. amtleata (Ehl'enberg) 2,3. * Foot-glands in transverse series.

Pleuretra gen. novo Discopus Zelinka 25. No rostra1 lamellae, viviparous. Oviparous'; :J bdominal transverse skinfolds numerous and not corresponding to segment boundaries. D. synaptae Zelinka 25.

P. alpi~tn1(Ebrenberg) 10. I P. b1'ycei (Weber) 47. ** Foot-glands in longitudinal series. P. h~tmerosa(Murray) 55. Anomopus Piovanelli 53 Foot elongate. Skin usually smooth and flexible. tt A. telplmsae Piovanelli 53. Embata gen. novo Mniobia gen. novo Spurs usually long and heeled j animals mostly ectoparasitic Foot short. upon water-dwelling larvae, isopods, etc. ; viviparous or oviparous. M. magn(~(PlatE') 27. .111.tetmodon (Ehrenberg) 7.

E pa1'asiticc~(Giglioli) 12. E. laticeps (Murray) 55. M. 1'~~sseola(Zelinka) 29. M. cwmata (Murray) 55. / E. lwmata (Murray) 58. E. commensalis (Western) 35 M. symbiotica (Zelinka) 20. ],£. incmssata (Murray) 55, E. laticomis (Murray) 55, l 11£.sC(t1'latin'a (Ehrenberg) 10. J11.circinata (Murray) 61. 78 D. BRYCEONA NEWCLASSIFICATIONOF THE BDELLOIDROTIFERA. D. BRYCEONA NEWCLASSIFICATIONOF THE BDELLOIDROTIFERA. 79

decurrent, so that in dorsal view they are partially visible to IlL FAMILY Microdinidae Murray 55 right and left of the head. The brain is moderately remote Bdelloids with fully developed but non-revertile rostrum. from the antenna, which in recent examples seems to be short, Corona absent or represented by few cilia about the mouth. but was perhaps not fully protruded, as early notes describe 1 genus. it as long. It is, however, by no means infrequent among Microdina l\'lurray 55 Bdelloids to keep the antenna partially invaginated. In the Toes four. feeding position the lumbar segments show dorsally the two 11£.pamcloxct Murray 55 prominent longitudinal skinfolds familiar in some other species but not universal, and which I propose to distinguish as "the lumbar plicae." The mastax is rather small; the rami about 13 p. long, each with six or seven very fine teeth. In most examples Scepanotrocha rubra sp. novo (PI. 2, Fig. 1.) the digestive fI uid is distinctly tinted, usually reddish pink, SPECIFIC CHARAC'l'ERS: Hood-like expansion slightly convex, occasionally pale brown. In the act of creeping the foot is dis­ without median notch or lateral projections j hinder margin ex­ tinctly shown. It consists of three segments, and the spurs are cised, merging into upper lip. Rami with six or seven fine teeth. short cones with an unusually blunt appearance in dorsal view. Spurs short blunt-looking cones, with small interspace. My largest examples measured about 220 p. when fully ex­ When creeping about, this species has some resemblance to tended, about 170 p. when feeding. young examples of Hab1'ot1'ocha const?'icta (Duj.), especially if This interesting species has been known to me, albeit imper­ colourless, yet may be distinguished by its more slender head and fectly, for many years past. I have notes of its occurrence in general outline, its more uniform width, and the blunt-looking, less sphagnum from Epping Forest, Sandown,I.\V., Callander, Pit­ divergent spurs. When newly obtained from moss-washings it lochry, and Stuttgart. Some months ago I found several examples is exceedingly restless and marches about vigorously. After a in sphagnum kindly sent to me by Dr. V. A. Latham, of Chicago, few days' isolation it becomes very quiet and displays its corona and these have enabled me to improve my acquaintance with its quite freely. While feeding it remains affixed with the foot, and peculiarities. I have never found it in other mosses, and look does not drift about, nor does it readily move away. upon it as almost as distinctively a sphagnum form as is The outline of the "hood" is best seen in young individuals, lIabrot?'ocha roepe?'i (l\'lilne). where it is distinctly broader than the corona, having a breadth of about 24 p., a depth of about 9 p.. The lateral margins are Scepanotrocha corniculata sp. novo (PI. 2, Fig. 2.) rounded off and the anterior is really slightly curved, but is fre­ quently sufficiently depressed to give the central portion a :flat SPECIFIC CHARACTERS:Membranous hood-like expansion, having outline. Posterior'ly the" hood" merges into the upper lip, but I anterior median notch, two small lateral processes, and a straight have thought that I could now and again distinguish a faint but posterior margin. boldly curved line marking the actual transition. Below the From ground-moss collected for me at Bournemouth early in " hood," the trochal discs appear to occupy the nor'mal position, 1909 I obtained a single specimen of this curious form, whose having their planes about transvet'se to the body-axis, but the striking divergence from the customary type I did not detect cilia on the dorsal portions of the discs are comparatively feeble, until, some weeks after its isolation, I first saw it feeding. The and the" cog·wheel" appearance is only presented by the cilia membranous expansion (seemingly of the upper lip) was per­ on the ventral portions. The short pedicels are approximate but fectly tran~parent,and the position of the trochal discs upon distinct. The" cheeks," or lateral cushions of the mouth, are the ventral side could be defined, although I could not see thickened, externally and ventrally prominent, and somewhat whether they were quite prone or somewhat obliquely placed. 80 D. BUYCE ON A NEW CLASSH'ICATLON OF THE BDELLOID RO'l'IFEUA. D. nRYCE ON A NEW CLASSIFICATION OF THE BDELLOID R01'JFERA. 81

In dorsal view the cilia of the discs were partially visible beyond LIST OF SPECIES O~II'rTEDFROM OLASSIFICATION AS INSUFFICI­ the front>tl margin, and appeared as though flanked by longer ENTLY DESCRIBED OR OTHERWISE INVALID. WITH REMARKS. bristle-like setae (?), whose nature I was unable to determine, Mc~cr'otr'achela,bidens Milne 18. although I supposed them to be possibly homologous with the Actinur'us neptunius Ehr. 2 & 3 Philodina hirsuta Ehr. 5. trochal setae-pencils possessed by many Philodinidae. (= Rotife?' actinurus Janson). This original example had some difficulty in extending and Adineta allaudi Oertes 70 " gmcilis Schmarda 11. oculatc~(Milne)" CalcWYltcl Schm. 11. using its foot, which I never saw protruded or affixed. Thus (=A. 18). Callidinc~elegans Ehr. 2 & 3. " nUlC?'(]siphoSchm. 11. when extended the animal was never still, either sprawlinO'0 about as it tried to creep, or when the corona was displayed " r'edivivcl EhI'. 45 & 7. " setifem Schm. 11. " tuberculatc~Gosse 19. being driven slowly along by the ventrally placed cilia. I " tr'iodon EhI'. 7. " cinnabarin(~Zacha- failed therefore to ascertain the number of teeth, but thought " hexaodon Ehr. 7. rias 69. that each ramus had three or four. When the corona was " oktodon' Ehr. 7. hexodontc~ pigr'c~ Bergendal withdrawn, and with it the distinctive "hood," the rotifer did " Gosse 21. " 31. not present any obvious peculiarity save that the head seemed " bihamata Gosse 19. micr'ops Gosse 22. somewhat long and the rostral lamellae rather large and pro­ " SOciCllisKellicott 24. " pcwasiticcl Marchoux minent. The anterior margin of the "hood" had a central " sor'dida Vvestern 35 " 49. angular depression, from which it cl1rved outwards to right, ( = Rotifer longi1'ostr'is Janson). decurvicor'nis Murra y and left till it arrived at the lateral processes, which were " laevis Bergendal 31. 51. somewhat pointed and ventrally defiexed. Their tips were " tentaculata Bel'. 31. " obesa Murray 51. about 35 I-'- apart. Behind them the "hood" seellled to be " lutea Zelinka 29. " emini Oollin 45. abruptly truncate, the hinder edge forming a straight line, " miiller'i Zel. 29. Rotife?' er'ytlwaens Ehrenberg 3. behind which could be seen the reverted rostrum. " lwlzinger'i ZeJ. 29. " maxirnus Bartsch 14. A second example was hatched from an egg produced by " lejeuniae Zel. 29. " motacillcl Bartsch 14. the original individual. In the young specimen, which did not " venusta Bryce 44 " megclcer'OSSchmarda 11. long survive, the points of the "hood" had a rather backward " H abrotr'ocha " tClnlus Ehr. 4 direction. The foot was· Ilormally protruded and occasionally (= elegans (Milne). (= Rotifer' tar'd'igmdus affixed, but usually the young rotifer swam slowly along like cataracta Lord 48 Ehr.). its parent. The foot seemed to have three segments: the first " " haptieus Gosse 19. rather long and dOl'sally swollen; the second small, with short, (= Pleur'etm br'yce'i (Weber». " plwlenltus Glascott 39. cone-like spurs, about 6 I-'- long, and without interspace; the quadr-idens Hilgen­ " quadr'ioc~llatu8Murray post-oral segment W~tSlaterally thickened, and carried a rather 11 dorff 46. 51. short antenna. The stomach contained distinct food-pellets. " or'nata 51. " f01:ficr.tlatus Barrois & The length of the adult example was estimated as about 2051-'-. Murray Hydr'ias cor'nigem Ehr. 3. Daday 42. Monolc~bisconica EhI'. 2 & 3. " inflatus Dujardin 6. DESCRIPTION OF PLATE 2. " gracilis Ehr. 3. Tvphlias vir-idis EhI'. 3. ,/ Fig. 1. ScepanotrochCl r'urn'a sp. nov., dorsal view. I.-CcdlidinCl elegans has appeared so frequently, both in local c:i " 2. " cO?'nic~~latasp. nov., dorsal view. lists and in more important works, as an accepted and valid . b. Oorona from ventral side. c. Foot. species, that it is incnmbent upon me to enter more fully than I if! j d. Dorsal antenna. should otherwise do into the reasons which force me to discredit /4.~ 82 D. BRYCE ON A NEW CLASSIFICATION OF THE BDELLOID nOTIFERA. D. BRYCE ON A NEW CLASSIFICATION OF THE BDELLOID ROTIFERA. 83 all the identifications which I have seen of this elusive species. Hudson and Gosse (19) as his species. These authors neith(lr It has first to be noted that, although Ehrenberg mentions it confirm nor deny the accuracy of Ehrenberg's statements. Yet both in 1830 (2) and in 1831 (3), the few particulars he gives they state that the form recognised by them as his C. elegans has (on the latter occasion) may be taken as superseded by those an antenna longer than the width of the corona, that it has three given in 1838 (4), since in the interval he had found the species toes, that the spurs are middling, and that the foot is thick­ on two occasions (but from the same locality as the original a final detail which is important, since it contradicts the capture). Further, that his description of the genus Callidina resemblance to P, m'yth?'ophthalma, which has a foot as long was based on this one species only, as the second known to him­ and as slender as that of P. ?'oseola. That Hudson and Callidina ?'ediviva, also mentioned in the same work (4)-was Goase's species had no prominent teeth does not perhaps conflict only found about the time when the proof-sheets were already with Ehrenberg's description of the rami as having many fine under revision. Thus the identity of C. elegctns is to be judged teeth. not only from the specific description, but also ft'om the descrip­ It has, however, seemed to me to be possible to recognise the tion of the genus Callidina, wherein particulars are given which animal which Hudson and Gosae had in mind. Their description have much importance. Collating both descriptions, it is to be of the corona is the one happy touch which indicates a species gathered that G. elegans of Ehrenberg was a blind Philodine, common enough in weedy pools. They say that the corona is oviparous and spindle-shaped, having a stout ciliated rostrum scarcely wider than the body, the double disc being very little and a long-extending foot with two spurs and four toes; a corona more than a full circle or two circles very slightly separated, of two small discs, not mounted on pedicels; rami with many very The species to which this description in my opinion applies the fine teeth; stomach thread-like; antenna short; with some re­ best has a number of fine teeth, a corona with discs whose semblance to Philodina eryth?'ophthalma, but with spurs somewhat pedicels are somewhat squat or truncate, and in these details longer than in that species yet shorter than in P. macrostyla, would not appreciably conflict with Ehrenberg's description; and with very short terminal toes. Some seven figures are given but the foot has no resemblance to that of P. m'yth?'ophthalma, the to supplement this description, and are principally noteworthy spurs have a most distinctive form not suggested by either of the for the curious presentment of the corona, which gives some authors, and, above all, the species has a wide l~trnenand is ground for Milne's (18) interpretation of it as of the Adineta distinctly a pellet-makm'. type, and which certainly gives no clear suggestion of any form It is probable that the form which Janson (38) cursorily of corona known to me. describes as Ehrenberg's species is identical with that of Hudson The description of the stomach as thread-like (" fadenartig ") and Gosse, if one may judge from his description and figure of in the generic description is to be understood as refening to the spurs. He states that the foot has only three segments, that G. elegans. In the description of G. ?'ediviva, interpolated at the the rami have ten to eleven fine teeth, and that the antenna is time of proof-revision, Ehrenberg notes as a conspicuous mark somewhat large. the breadth of the food-canal, apparently meaning the lumen of Ehrenberg was possibly mistaken as to the numbel' of toes. the stomach, and he speaks of the stomach-structure as resembling It is known that he was inaccurate on this point with respect to that of P. colla?'is. It is clear from the further details given the genus Rotifm', while correct with regard to the genus that both P. collw'is and G. ?'ediviva had stomachs with a wide Philodina. But I cannot think that he would have failed to lumen, and that both were pellet-makers. That such is the case distinguish between the short stout foot of Hudson and Gosse's with G. ?'ediviva gives the more weight to the description of the G. elegans, and the long slender foot of P. eryth?'ophthalmct, and that stomach in G. elegans as thread-like. he would only be able to distinguish the two species by examina­ 1£ one may rely on the various details given by Ehrenberg, tion of the rami, as in effect he states with regard to his C. elegans, his G. elegctns differs in several respects from that described by And again, I cannot brush aside his statement that the stomach 84 D. BRYCE ON A NEW CLASSIFICATION OF THE BDELLOID ROTIFERA. D. BRYCE ON A NEW CLASSIFICATION OF THE BDELLOID ROTIFERA. 85 was thread-like, when I know how particularly he was interested 4.-CCtllidinct socictlis Kellicott is probably a good species, but in the structure of the alimentary canal and in the appear­ was quit.e inadequately described by its discoverer, who thought ances presented when the rotifers were fed with indigo or other it sufficient to differentiate his species from Philodina pct?'asitica pigments. as the only Bdelloid previously known to be ectoparasitic upon 2.-CaUidina 1'edivivct, as stated above, was clearly a pellet­ fresh-water animals, and omitted in particular to ascertain whether maker, and had a stomach with a wide lumen. It had two teeth it was oviparous or viviparo11s, and whether it had three or on each ramus, and some resemblance to Philodina 1'oseola in colour four toes. J anson, who considered that Roti/m' magnicalca1'ctta and form. It occUl'red in sand from a rain-water gutter in (Parsons) is identical with C. socictlis, assumed that the latter Ehrenberg's house. rrhese details were given in 1838. At a later was viviparous and had three toes like Parsons's species. In my date, 1848 (7), Ehrenberg states that the colour is brick-red and view it is quite as likely to have been oviparous and four-toed that the body is spindle-shaped. The two-toothed pellet-makers like P. commensalis vVestern (described as viviparous, but I think known to-day are comparatively few. The above particulars in error). There are now known'quite a number of these ectopara­ apply best in my opinion to Hctbrot1'ocha bidens (Gosse), which sitic species, and any 'amended description of the true C. socialis has the spindle-shaped body and a superficial resemblance to would have to take these into consideration. Meanwhile I retain P. roseolct; but I have never seen it of a reddish colour, but always as valid the R. magnicalca?'ata (Parsons), which I have repeatedly colourless or nearly so. To regard the two forms as identical found and which is a much larger form than that described by on such faint particulars and resemblance would not, I think, Janson, attaining somE'times a length of 720 p. or le; inch. be satisfactory. Janson's dimensions and details apply very well to another 3. - Philodina hi1'suta, Ehrenberg, wrongly ascribed to smaller form, found by Murray in Scotland and myself in Pritchard by Janson (38), appears to have been accepted by the England, which has thesftme sword-like spurs as P. commensctlis last author solely upon the faith of its supposed recognition by and R. magniccdca1'ata, and like these species is usually found on Anderson (30), who in turn seems to have been misled by a Asellus. This third form resembles P. comrnensalis very closely ludicrous error in Pritchard's Infitso1'ia (1861 edition). In in general appearance, but is viviparous, three-toed, and blind. Ehrenberg's description the spurs are thus described: "Pedis In P. cornrnensalis the eyes are frequently very difficult to define, corniculis dorsualibus praelongis," the phrase meaning in modern and I ltm inclined to believe that vVestern took the character terminology "Spurs very long," but translated in Pritchard " viviparous" from examples of this third form which he had as "Foot prolonged by dorsal spines." Anderson remarks that failed to distinguish from the true commensctlis. the foot is not prolonged by dorsal spines, and figures a species 5.-Philodina hexodonta Bergendal. A form found some years with quite short spurs, which cannot possibly be the species seen ago in Scotland by Murray, and more recently by myself, was by Ehl·enberg. If Philodina commensalis of Western be really at first referred to the above species, in view of the approxi­ viviparous as described (of which I have doubts) it is possible mation of the number of teeth (5-5) to that stated by Bergendal. that it is a rediscovery of the original P. hi1'S'UtCt,as not only It differs from it, however, in almm;t every other detail given does it fit the few particulars given by Ehrenberg, but I have also by that writer. For instance, P. hexoclonta is said to have a seen it partially covered with hair-like bodies, noticed both by body resembling that of P. roseola, but not reddish; and to Ehrenberg and by Anderson on their respective species. It is . have spurs so swollen at the base that there is no interstice now well understood that the supposed "down ,. does not really between them. The Scottish form is quite unlike P. 1'oseola in appertain to the rotifer, but is a parasitic fungoid growth, either general outline; the proportionate length of the foot is very a species of Cladothrix or allied thereto. A similar growth was different, the body is often reddish, and there is a distinct seen on examples sent to me of Anomoptts telphusae, which, like interspace between the short, acute spurs. P. commensalis, is itself of parasitic habits. After further consideration I came to the conclusion that 86 D. BRYCEONA NEWCLASSIFICATIONOF THE BDELLOIDROTIFERA. D. BlWCEONA NEWCLASSIFICATIONOF THE BDELLOIDRO'l'IFERA. 87 the Scottish specimens must be referred to the Philodina eoUal'is known, and which in certain positions might appear to be of Ehrenberg, a species hitherto unrecognised. It is unfortunate crossed hooks if imperfectly seen. that with regard to this very species Ehrenberg was unable to 8.-Callidina pig?'a Gosse is probably Hab?'ol?'oeha eonst?'icta state the number of teeth, as this detail would have been of (Dujardin ). great value. But I rely less upon the general details given of 9.-C(tllidina angusta Bryce. I had proposed to include this P. eolla?-is than upon the description and figure of the stomach, species in the doubtful list, but whilst these notes were in which prove clearly enough that this species was a pellet-maker, preparation I have been informed by Mr. Murray that he has and had a stomach with the wide lumen usual among pellet­ recently found specimens which agree fairly well with the making forms. details noted in my deseription, .although this could perhaps The Scottish species is the only pellet-maker known which be amplified with advantage. Judging from his specimens he has two eyes in the neck, or, to locate them more precisely, thought that the species seemed to be related to Callidina habita in the brain, and it further agrees with Ehrenberg's description Bryce. in having a small corona, and in the eyes being round. I did 10.-Philodina pamsitiea Marchoux is probably a distinct not observe in my own specimens that there was any distinct species, but the description is very insufficient, and the specific swelling of the neck such as Ehrenberg describes; but he appears name has been already appropriated to Giglioli's species, which to indicate that annulus-like thickening of the skin of the post­ would possibly prove to be a congener. oral segment which is noticeable in many species. As these 11.-Callidina o?'nctt(t, Rotife?' q~ladrioe~tlcttu,s,Philodina obesa, are nearly all pellet-making forms, this detail supports my view and P. deew'vieornis, all described by Murray, are now regarded that P. eolla?'is was a pellet-maker. In accordance with that by him as doubtful, pending further examination. view, and in the belief that the Scottish specimens are more correctly to be assigned to P. eolla?-is, I have included Ehren­ BIBLIOGRAPHY. berg's species as recognisable, and placed P. hexodont(~among those which are insufficiently described. Restricted to works dealing with the classification of the It seems probable that the specimens which Bilfinger (68) BDELLOIDA,or containing original descriptions or supplementary assigned to P. hexodonta were similar to the Scottish examples. details of species. 6.-Rotifer h(~ptieusGosse. Neither Murray nor myself has met with any species which rivals R. mam'oceros in the length v 1. 1803. SCHRANK: Fauna boiea, IH., 2, p. 110. of the dorsal antenna but lacks the tapping motion character­ v 2. 1830. G. O. EHRENBERG: Beitrage zur Kenntniss del' istic of the latter form. But the whole description given by Organismen del' Irlfusorien, etc. Abhand. de)' Gosse is. so lacking in definite detail that there can be no question Berline)' Ak(td. de?' WiS8. of its insufficiency. Indeed, the whole central group of the G. O. EHRENBERG: Uber die Entwickelung und genus Rotifer, viz. R. mdga?'is and its nearer relations, amongst Iv 3. 1831. Lebensdauer del' Infusionsthiere, Abltand. de)' which R. haptieus is probably to be reckoned, stands greatly Berline)' Akad. de?' TViss. in need of a much more critical examination than it has yet G. O. EHRENBERG: Die Infusionsthierchen als voll­ received. v 4. 1838. kommene Organismen. 7.-C(~llidinabihamat(~Gosse. The value of the description of this species rests solely upon the reality of the two "hooks" "- 5. 1840. G. O. EHRENBERG: Note in Ve?·hand. de?' Berliner at the apex of the rostrum. It seems certain that the supposed Akad. de)' Wiss., p. 197. "hooks" were simply the lateral presentment of the rostral .,; 6. 1841. M. F. DUJARDIN: Histoire naturelle des Zoophytes; lamellae, possessed more or less conspicuously by every Bdelloid In£usoires in, Sltites er,Bl~t!on. 88 D. BRYCE0)[ A NEWCLASSIFICA'l'IONOF THE BDELLOIDROTIFERA. D. BRYCEONA NEWCLASSIFICATIONOF THE BDELLOIDRO'l'IFERA. 89

7. 1848. G. C. EHRENBERG: Fortgesetzte Beobachtungen libel' 22. 1887. P. H. GOSSE: Twenty·four more New Species of

atmosphaerische Mikroskopische Organismen, Ve?'­ Rotifera, Joum. Roy. ~Mic?·.Soc., p. 861. hand. der Berliner Akad. de?' Wiss., p. 380. 23. 1888. \V. MILNE: Rotifer as a Parasite or Tube-dweller, 8. 1851. P. H. GOSSE: A Catalogue of Rotifera found in P?'oc. Phil. Soc., Glasgow. Britain, Ann. jl{c£g. Nat. Hist., Sel'. II., Vo1. VIII. 24. 1888. D. S. KELLICO'l"l': Pa,rtial List of Rotifera of Shia­ v 9. 1852. PERTY: Zur Kenntniss del' kleinsten Lebensformen. wassee River, P?·oc. Ame?'. Soc. jl{ic?·., Vol. X, 10. 1853. G. C. EHRENBERG: trber neue Anschauungen des 25. 1888. CARL ZELINKA: Del' Raumparasitismus und die kleinsten nordlichen Polarlebens, Verhand. de?' Anatomie von Discopus Synaptae; Studien libel' Bm,lin Akad. de?' Wiss.; p. 529. Riiderthiere, Zeitsch. f wiss. Zool. (Jena), Bd. J 11. 1857. L. K. SCHMARDA: Neue wirbellose Thiere, etc., Bd. I., XL VIlI., p. 353. pp. 47-66, 26. 1888. E. F. 'WEBER: Notes sur quelques Rotateurs des 12. 1863. H, GIGLIOLI: On the genus Callidina, Quart. JMwn. Environs de Geneve, Arch. de Biologie.

jl{icr. Science, N. S., V 01. Ill., p. 237, \ 27. 1889. J~.PLATE: Uber die Rotatorien-fauna des bottnischen / 13. 1868. E. RAY LANKESTER: Note on the Synaptae of Meerbusens,Zeitsch.f. wiss. Zool.(Jena),Bd. XLIX., Guernsey, etc., and a New Parasitic Rotifer, Qt£art. r. 1. Journ. Micr. Science, N. S., Vol. VIII., p. 53. 28. 1890. G. WESTERN: Notes on Phil. macrostyla and Rotifer 14. 1870. '"' S. BARTSCH: Die Riiderthiere und ihre bei Tlibingen citrinus, Jotorn. Qt£ek. l.£icr. Club, Ser. IT., Vo1. IV., beobachteten Al'ten, Jah?'eslMfte des Vereins fii?' p.87. Vaterlcindische Naturkunde tn Wiirttembe?'g, 29. 1891. CARL ZELINKA: Zur Entwickelungsgeschichte del' Stuttgart. Riiderthiere, etc., Studien libel' Riiderthiere, Zeitsch. ../ 15. H173. H. DAVIS: A New Callidina, etc., l.£onthly Mic?'. f wiss. Zool. (Jena), Bd. LIII., p. 323. Joum., Vol. IX., p. 201. v 30. 1891. H. H. ANDERSON: Notes on Indian Rotifers, Journ. v 16. 1877. S. BARTSCH: ~tatoriaHungariae. Asicotic Soc. Bengal (Calcutta), Vo1. LVIII., p. 345. 17. 1884. C. T. HUDSON: An Attempt to reclassify the Rotifera, 'v 31. 1891-2. D. BERGENDAL: Beitriige zur Fauna Gronlands, Qucwt. Journ. Micr. Science, N. S., V 01. XXIV., I. Zur Rotatorienfauna Gronlands, Kongl. Fysiog. p.335. . SCillskapets Handlingar. 18. 1886. W. MILNE: On the Defectiveness of the Eye-spot as a 32. 1892, F. A. PARSONS: Notes on Two Rotifers found in of Generic Distinction Philodinaea, l Means in the Epping Forest, Jow'n. Qtoe1c.jl{icr. Cltob, Ser. II., etc., Proc. Phil. Soc., Glasgow. Vol. IV., p. 378. 19. 1886-9. C. T. HUDSON & P. H. GOSSE: The Rotifera or 33. 1892. DAVID BRYCE: On the M:acrotrachelous Callidinae, Wheel Animalcules, 2 vols., 1886-7; Supplement, JotW'n. Qtoe1c.jl{icr. Club, Ser. II., Vo1. V., p. 15. 1889. 34. 1892. P. G. TIIOMPSON: Moss-haunting Rotifers, Science 20. 1886. CARL ZELINKA: Uber die Symbiose und Anatomie Gossip, V 01. XXVIII., p. 56. von Rotatorien aus dem genus Callidina; Studien 35. 1893. G. 'WESTERN: Notes on Rotifers, etc., Jou?·n. Que1c. libel' Raderthiere; Jen. Zeitscl~.f Natunviss. Zool., Bd. XLIV., p. 396. 11ficr, Club, Ser. n., Vol. V., p. 155. 1/ 21. 1887. P. H. GOSSE: Twenty-four New Species of Rotifera, 36. 1893. DAVID BRYCE: On the Adinetadae, Jou?'n. Que1c.lJ;Iicr. JOtol'n. Roy. ll1ic?·. Soc., p. 1. Club, Ser. n., Vol. V., p. 146. 90 D. BRYCEONA NEWCLASSIFICATIONOF THE BDELLOIDROTIFERA. D. BRYCEONA NEWCLASSIFICATIONOF THE BDELLOIDROTIFERA. 91

37. 1893. DAVID BRYCE: On Two New Species of Macrotracbe­ 51. 1902. JAMES MVRRAY: Some Scottish Rotifers, etc., Ann. lous Callidinae, Jow·n. Que1c. llfim·. Cltbb, Ser. n., Scat. Nat. Hist., p. 162. Vol. v., p. 196. 52. 1903. JAMES MURRAY: S)me Scottish Rotifers (Bdelloida), 38. 1893. Ono JANSON: Versuch einer Ubersicht iiber die Ann. Scat. Nat. Hist., p. 160. Rotatorien-FamiJie del' Philodinaeen, Abhand. der v 53. 1903. SEBASTIANOPIOVANELLI: Two New BdeJloida COlll­ lYattb1·wiss. Ve1'eins in Bremen. mensal in the Branchial Cavities of Telphusa 39. 1893. L. S. GLASCOTT(Miss): A List of some of the fluviatilis, Jo~wn.Q~w1c..Micl'. Club., Ser. n., Vol. ltotifera of Irela.nd, Proc. Ray. D'ublin Soc., VIIL, p. 521. Vol. VIII. (N. S.), p. 29. 54. 1903. DAVID BRYCE: On Two New Species of Philodina,

40. 1893. E. VONDADAY: CypridicoJa parasitica, Te1"1neszetmJzi J01.b1·n. Q~tek.lJ£im'. Club., Ser. II., Vol. VIIL, Fusetelc X VI. p.523. 41. 1894. DAVID BRYCE: Further Notes on Macrotl'acheJous 55. 1905. JAMES MURRAY: On a New Family and Twelve New Callidinae, Jo'm'n. Quele. Micr. Soc., Ser. n., Species of Rotifera of the Order' Bdelloida, etc., Vol. V., p. 436. T1'Cbns.Ray. Soc. Edin., Vol. XLL, p. 367. ~ 42. 1894. THEOD. BARROIS& E. VONDADAY: Resliltats Scienti. 56. 1906. JAMES MURRAY: The Bdelloid Rotifera of the Forth fiques d'un Voyage entrepris en Palestine, etc., Area, P1'OC.Ray. Phys. Soc. Edin., Vol. XVI., p. 215. Rotijel'es, Revue Biologique dtb 1\Tm'd de la Ji'mnce, 57. 1906. JAMES MURRAY: A New Bdelloid Rotifer, Callidina LilJe. vesicularis, Jow·n. Quele. Mic1'. Cltbb, Ser. 11., \.... 43. 1895. B. NE~iEC:O. ectoparasitech Ligidia, Vestnile J{1'Iil Vol. IX., p. 259. Ceslee Spoleooosti NCbUle,Prague. 58. 1906. JAMES MURRAY: The RoLifera of the Scottish Lochs, 44. 1897. DAVID BRYCE: Contributions to the Non-marine Tmns. Ray. Soc. Edin., Vol. XLV., p. 151.

Fauna of Spitsbergen, Part n., Report on the 59. 1906. JA~iESMURRAY: Some Rotifera of the Sikkim X Rotifera, P1'OC.Zool. Soc., London, p. 793. Himalaya, Journ. Ray. Mic1·. Soc., p. 637. U 45. 1897. A. COLLIN: Eingeweidewllrmer und Rfiderthiere, \.../ 60. 1907. JAMES MURRAY: Some South American Roti1ers, Die Thie1welt Ost-Afri1ccbs, etc., Vol. IV., Part V. Ame?·. lYat. (Boston), Vol. XLL, p. 97. (Carl Moebius). 61. 1908. JAMES MURRAY: Scottish Rotifers collected by the 46. 1898. F. W. HILGENDORFF:A Contribntion to the Study of Lake Survey, Tmns. Ray. Soc. Edin., Vol. XL Vr., the Rotifera of New Zealand, Tl'ans. .LV.Z. Inst., p.189. Vol. XXXL, p. 108. v 62. 1908. J AMES MURRAY: Arctic Rotifers, etc., P1·OC.Ray. 47. 1898. E. F. WEBER: Faune Rotatorienne du Bassin du ~ Phys. Soc. Edin., Vol. XVII, p. 121. Leman, Revue Suisse de Zoologie, Geneva, Tome V. 63. 1908. JAMES MURRAY: PhiJodina macrostyla and its Allies,

48. 1898. J. E. LORD: On Two New Rotifers, JOtb1'1~.Quele. Micr. )( Joum. Qtwle. ]v[icr. Cl1bb., Ser. n., Vol. X., Club, Ser. n., Vol. VII., p. 75. p. 207. \, 49. 1898. E. MARCHOUX: Note sur un Rotifere vivant dans le 64. 1908. JAMES MURRAY: Some African Rotifers, Jonrn. Ray. tube digestif de larves aquatiques d'insectes, Mim·. Soc., p. 665. Compte Rendtb Soc. Biol., Tome V., p. 749. 65. 1909. P. DE BEAUCHAMP: Philodina intermedia n. Sp. et 50. 1899. C. 'VESENBERG LUND: Danmark's Rotifera, Copen­ Remarques sur l'origine des Microdinides, Btbll. hagen. Soc. Zool. de Ji'mnce (Paris), Tome XXXIV. 92 D. BRYCEONA NEWCLASSIFICATIONOF THE BDELLOIDROTIFEllA. Journ.Q.M.C. Ser 2 Volll. P12 66. 1910. JAMES MURRAY: Ant:uctic Rotifera, Brit. Antarctic Expedition, 1907-9, Repo7·ts on the Scientific In­ vestigations, Part Ill. 67. 1902. FERD. RICHTERS: Neue Moosbewohner, Be7'icht de7' Senckenbe7'gischen N attwfcwschenden Gesellschaft in Fretnlcftl7't a/11£. 68. 1894. L. BILFINGER: Zur Rotatorienfauna Wiirttembergs, Jah7'eshifte des Ve7'eins fii7' vate7·l. Nattwkunde in Wii7·tt. 69. 1886. O. ZACHARIAS: Konnen die Rotat. u. Tard. nach vollsUindiger Austrocknung wieder aufleben oder nicht 1 Biol. Centretlbl., Bd. Vr., p. 230. 70. 1903. CERTES: Microbiologie, Mem. Pontif. Accad. Rornan. dei 7Mwvi Lincei (Rome), Vol. XXr., p. 26.

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Jou,,'n, Quekett .fti!ic,,'osrJopical Club, Ser, 2, Vol, XI" No, 67, November 1910. 2b. llJ3ryce. aeL .il..K SearJe.L.th.. ScepOJWtr00% gen.et sp.noy.