52 A Rotifer Neiv to Britain. 



The specimens that I have seen were remarkably translucent 

 and free from colour; but the outlines of the internal organs 

 are so evanescent as to be difficult of determination. The 

 digestive system shows a mastax, of the form of that seen in 

 Limnias, which I have represented in "Phil. Trans." 1856, 

 pi. xviii. figs. Q6 — 71. From this a short oesophagus leads to 

 a wide and long stomach, extending down the dorsal half of the 

 body-cavity, and merging by a constriction into a short intestine, 

 whence a slender rectum turns abruptly upward, and opens by 

 a cloaca seated between prominent points, capable no doubt of 

 a very great protrusion at the moment of evacuation. As I 

 have before observed, I have not in any instance seen the 

 alimentary canal occupied by food ; in each case, the stomach and 

 intestine were transparent, save for some minute oil-bubbles and 

 pellucid specks, and were tinged with a pale yellow hue, probably 

 owing to effusion from the surrounding biliary glands. 



The whole ventral half of the cavity is filled by an almost 

 commensurate ovary, which in these specimens contained only 

 undeveloped ova, in their usual form of clear, highly refractile 

 sphericles, each with a dim nucleus. 



The nervous system shows a comparatively large brain, 

 seated as a defined gray cloudy mass of irregularly lobed form, 

 immediately below the antenna, and behind the discal mammilla 

 (Fig. c). The structure that permeates the antenna, whether 

 tube or nervous thread, expands upon, and is lost in, this brain- 

 mass; and on its side I saw, with great distinctness, in one 

 specimen, a bright crimson eye-speck. I could not, by focussing, 

 get a glimpse of the eye on the opposite side, perhaps from the 

 opacity or the unequal refrangibility of the intervening tissues ; 

 but the position of this one implied that it was one of a pair. 

 In no other specimen could I find a trace of eyes. 



I have not been able to see any muscular bands or threads. 



The Cejplialosiphon is very lively and active in its motions. 

 It is very ready to protrude from its case ; and not at all prone 

 to retire upon ordinary alarms, such as a jar upon the instru- 

 ment, that would send the Floscularia or the Stephanoceros into 

 its retreat in an instant. It is very curious to see it protruding ; 

 the long antenna is first thrust out, and jerked to and fro, as a 

 feeler, exploring the surrounding water for safety. This being 

 assured, a considerable portion of the body projects, with a 

 quick jerk, which then, by its bowings and turnings, seems to 

 aid the antenna in its investigations ; presently, a good piece 

 more of the body comes out, until at last we see the commence- 

 ment of the wrinkled foot itself; the jerking and feeling still 

 going on. Perhaps I have not been fortunate in my specimens ; 

 but I have not witnessed the opening of the disk in any 

 instance ; and the animal appears chary of exposing its facial 



