34 THE ROTIFERA. 



from the circumstances, I dare not vouch for the minute details, particularly of the 

 incus-rami. The respiratory organs, in the form of slender cords, loosely twisted 

 together, but, as I presume, tubular, can be traced to the very front of the head ; at 

 least to the point on each side where the proximity of the brain to the integument 

 allows them to be no longer discerned ; and thence backward without interruption, till 

 their ends ramify and are lost on the walls of the ample contractile vesicle that occupies 

 the termination of the abdominal cavity. It was an operation of much delicacy, but 

 with a ^-in. obj. I think I satisfactorily followed the entire course described. In the 

 ample abdomen the viscera are large. The alimentary canal is clearly separated into a 

 stomach and an intestine. In all the individuals examined, neither of these held any 

 visible food, but both were tinged with pale umber-brown. An ovary of embryonic 

 vesicles, and a great dark ripening ovum, were conspicuous in one. At the expansion 

 of the long oesophagus into the stomach are the pair of ovate colourless glands, which 

 possibly are biliary, and may impart the prevalent yellow-brown tinge to the digestive 

 canal. The dorsum, just before the point where it contracts into the foot, rises into an 

 angular prominence ; which must be regarded as a true tail, because beneath and behind 

 it is the common excrementary outlet, whether for matters urinary or fecal the cloaca. 

 The anterior side of the orifice is crowned with a bristled tubercle (fig. 5d), very closely 

 resembling that projecting from the hind head. It seems a tubular wart with a thick- 

 ened rim, bearing a rather short seta on the summit. From the base of this are 

 discerned, clearly running down through the transparent tube, two fine lines, which 

 probably are the optical expression of a nervous cord, bending forward to some sensible 

 distance up the body, till lost behind the viscera. I searched (vainly) for some ganglion 

 in the vicinity, with which this thread may communicate. But I rather presume that 

 it runs through the body, and communicates with the great brain at the very front. It 

 seemed to me that each of these tentacular warts, both that on the head and that on 

 the tail, is susceptible of sensible elongation, and of occasional withdrawal, partial or 

 perfect. The foot is slender and colourless, like the anterior parts, and is terminated by 

 two minute and delicate toes ; from which two long, club-shaped muscles pass forward 

 nearly to the cloaca. 



The species was discovered by Dr. Collins in 1865, in a small pool near Sandhurst 

 Military College, whence he has recently sent me a supply. There seemed here the 

 exercise of a sense of companionship, at least in captivity. After some days this species 

 became rather numerous in the bottle of water-moss, and I have had, perhaps, a dozen 

 in my live-box at once, of various ages. I noticed, much too often to be merely 

 fortuitous, that they were in the habit of associating in couples, two being generally in 

 close contiguity, and now and then coming into actual contact ; the one crawling, in 

 their lithe embracing manner, over the foreparts of the other ; separating, however, 

 immediately after. It was not sexual. In young individuals, not more than half as 

 long as the adult, all the characters are developed ; except the great length and almost 

 invisibility of the neck, which are not so manifest. P.H.G.] 



Length, T ^ inch. Habitat. Sandhurst, Berks (Collins) ; Dundee (P.H.G.). 



C. CERBERUS, Gosse, sp. nov. 



(PI. XVI. fig. 3.) 

 Xotommata centrum . Gosse (nee Ehr.), Ann. Nat. Hist. 2 Ser. vol. viii. 1851, p. 200. 



[SP. CH. Tentacles wholly icanting (or unobserved}; auricles small ; brain three- 

 lobed ; tail a minute tubercle. 



This species approaches the ordinary Notommatce, in form and in the absence of 

 those projected organs of sense which characterise the other species of this genus. 

 Yet the general aspect, the sluggish manners, and the three-lobed brain, seem to war- 



