12 THE r.OTIFERA. 



Ceylon. It is a remarkable Rotiferon, surpassing almost every other in the number and 

 variety of its styles, setii?, and cilia. In general shape it is something like a Brachionus, 

 but its head is that of a Hydatina. There are only three styligerous prominences in 

 the corona between the two usual wreaths, and these bear stylos arranged fan-fashion 

 and thickened at the base, as if each style passed through a short sheath ; a form of 

 style strikingly visible in the young animal, when the styles are short. The whole of 

 the cavity leading to the buccal funnel is ciliated, and at its base is a ring of large 

 curved styles, pointing upwards. On each side of the wedge-shaped opening, at the 

 entrance to the buccal funnel, are large setie set horizontally above one another in short 

 sheaths, and fringed at their bases with minute vertical setfe (fig. Ic). The trophi are 

 malleate, and Mr. Gosse says that tbey are the exact repetition of those of N. clavulatus 

 {Notommata clavulata) as figured by him in " Phil. Trans." 1850, PI. xvi. fig. 23. The 

 rest of the nutritive system, as well as of the secreting and vascular systems, is obvious 

 and normal. The ovary is horseshoe-shaped, with its germs set in a single line. 

 There is a nervous ganglion just below the dorsal surface of the head, somev.hat rect- 

 angular in outline like that of Hydathia senta; and, like it, giving off nerve-threads at 

 its corners, two of which doubtless pass to the large dorso-lateral antennae shown at the 

 lower corners of the trunk iu fig. 1. Mr. Gosse, in a side view, has seen that the 

 nervous ganglion is a truncated pyramid, bearing the red eye on its summit. 



The Male. — N. brachionus carries its egg for some time after exclusion, so that it is 

 possible to identify the male with certainty. The male is very unlike its mother in 

 shape and size, and a side view (fig. lb) shows that the head slopes back to a hump, on tlie 

 apex of which is a bunch of tactile setae. A nerve-thread from the nervous ganglioa 

 passes to these, and lies between two fine muscular fibres. A moderately sized speim- 

 sac ends iu a ciliated penis just above the foot, which contains two large club-shaped 

 glands. Close to the sac is a small contractile vesicle, the lateral canals of w-hich can 

 be readily traced on either side of the ventral surface.' 



Length, ij',, inch. Habitat. Ponds and pools ; Clifton (C.T.H.i ; Kingswood (P.H.G., 

 T.B.) : not common. 



N. CL.wuLATca, Elurnbcrij. 

 (PL XV. fig. 8.1 

 Notommata clavulata . . . Ehrenberg, Die Infiis. 1S3S, p. 432, Tat. 1. fig. 5. 



SP. CH. Body sac-shaped; foot one-ninth of total length, icholly retractile tvithin 

 the veyitral surface; tropM malleate. 



At the first glance one would say that this animal was an Asplanchna, which genus 

 it gi'eatly resembles iu general shape, in brilliant transparency, and in the comparative 

 emptiness of the trunk. But a little examination shows that the tw'o are widely unlike 

 in corona, trophi, and alimentary canal. On comparing, however, the apparently dis- 

 similar creatures N. brachionus and N. clavulatus, it will be found that they are, in 

 many important points of their structure, exact counterparts of each other. The coronae, 

 for instance, are closely alike, although N. clavulatus has a greater number of styligerous 

 lobes, and lacks the ring of curved styles that lie round the base of the cavity of the 

 corona in N. brachionus (fig. 1). The trophi are identical. The muscular and vascular 

 systems are much alike ; the latter, indeed, curiously so, for the sharp bend at right angles 

 in the lateral canals, which is rendered necessary by tlie shape of N. brachionus, is 

 repeated (needlessly, as it were) by N. clavulatus. The contractile vesicle in the latter, 

 however, has much thicker walls, and is sluggish in action. The eye is seated on the 



' Ehrenberg found a female with a cluster of male eggs ; and, misled by their size and number, 

 supposed that the issuing young were those of a Notomviaia which he named JV. granularis, and 

 which he credited with laying its eggs on the backs of Brachioyius pala and Notops brachionus. 

 Leydig explained the error {Inr. cir.). 



