History of the Hairy -backed Animalcules. 405 



Sp. 12. T. annulosa {Gosse). (PL i. Figs. 17—19.) This 

 species and genus I defined in the Annals of Nat. Hist, for Sept. 

 1851 , collocating it with, the Notommatce and Furcularice, but 

 indicating its relations with Ghcetonotus. It occurred to my 

 researches in a pool near Leamington, in July, 1850. Its length 

 is about 1-1 10th of an inch. The form is very larva-like; the 

 body is sub-cylindrical or fusiform, terminating in a bifid foot ; 

 it consists of many rings or segments, which are set within the 

 clear cylindrical integument, and are themselves of a sub-square 

 form, with projecting angles. Thus a transverse segment would 

 present the appearance of Fig. 19 ; — a structure not easily ex- 

 plained. I could see no appearance of vortices, nor even the 

 vibration of cilia ; yet the form of the mastax is Rotiferous, and 

 appears closely to resemble that of Furcularia gracilis and of the 

 Monocercce, consisting of an incus, with a long fulcrum and a 

 pair of long incurved mallei. The animal can bring the tips of 

 the jaws to the front, and nibbles extraneous matters with them 

 like the Notommatce, etc. A long, wide, straight, cylindrical 

 alimentary canal, without any accessary glands or constriction, 

 leads from the mastax to the cloaca just above the forked foot. 

 It was in this specimen nearly empty, slightly tinged with yel- 

 low. All the rest of the animal was colourless. No eggs or 

 ovary were visible. At the occiput, behind the mastax, was an 

 opake mass, which was white by reflected light, but showed no 

 redness or appearance of eye, by either reflected or transmitted 

 fight. Like the cerebral ganglion in many Notommatce, it lay at 

 the bottom of a wide deep sac (Fig. 18). The animal contracts 

 strongly and continually like Notommata; but the sphere of the 

 contraction is the space occupied by the alimentary canal, the 

 parts outside the boundary lines of this remaining still, while 

 the parts within retract forcibly, and both ways, but chiefly 

 from behind forwards. In its movements it resembles Chceto- 

 notus, crawling sluggishly about the glass and the particles of 

 sediment. I never saw it attempt to swim. 



The number of genera has thus been increased, since Dr. 

 Schulze wrote his summary of the family, from four to six, and 

 of species from seven to twelve. With these augmented mate- 

 rials it seems to me that the judgment expressed by him as to 

 their affinities must be somewhat modified, and I have no hesi- 

 tation in recurring to the original decision of Ehrenberg, and 

 in placing the Chcetonotidce among the Botifera. Tortuous 

 canals and a contractile vesicle I have seen in C. larus, C. 

 Slackice, and Das. antennigcr : pancreatic (?) glands in C. 

 8lachio3 ; ciliary vortices are made by D. goniathrix and J), an- 

 tenniger, not to be distinguished from those made by many 

 Rotieeka, as Furcidaria, Notommata, etc. The egg-develop- 



