74 THE EOTIFEEA. 



Length, ^ inch. Habitat. Stratford ; Maidenhead ; Cheltenham ; Birmingham ; 

 Starmont Loch, Dundee (P.H.G.) ; pools and dykes : rare. 



S. EUDACTYLOTUM, Gosse, sp. nov. 

 (PL XXI. fig. 4.) 



SP. CH. Lorica. pear-shaped, depressed and narrowed in front; toes as long as all 

 the rest of the animal. 



[S. cudactylotum was discovered in September 1881 in a small loch in Perthshire, 

 by Mr. Hood, who sent me a tube of the water. This I found well peopled with this 

 charming species. It is much more globose than longicaudum, and much more trans- 

 lucent, looking like an oval bubble of clear glass. The head is small, formed of several 

 ciliated eminences. Among the turbid clouds, which are probably brain-matter, there 

 are one or two oval spots, which refract the light strongly ; but I cannot interpret them. 

 As a small red eye always moves to and fro with the movements of the mastax, I con- 

 clude that they are organically united as in longicaudum. The incus and mallei are 

 much more normal than in that species. The manubria, however, are tripartite, and 

 the middle joint is largely and somewhat irregularly looped. The apparatus is un- 

 usually minute, obscure, and difficult. The mastax is distinctly three-lobed. There 

 are a long O3sophagus, wide stomach, intestine, and small ovary with nucleated 

 ovarian vesicles. In one example was a small maturing egg. The longitudinal 

 muscles are numerous, and unusually conspicuous, owing to the brilliant trans- 

 parency. But the most remarkable feature is the foot of three articulations, with 

 strongly marked condyles, and a pair of furcate toes of excessive length and tenuity. 

 They are usually straight, but are sometimes a little curved outward at their tips. It is 

 graceful and elegant in its motions. I have never seen one resting, but invariably swim- 

 ming with a smooth even gliding, not at all rapid, often varied by a sudden spring or 

 skip to one side, like its fellow S. longicaudum. The toes are very flexible, and highly 

 clastic ; sometimes when the animal suddenly turns, I have seen the toes bent almost 

 double, but recovering their straightness in a moment. That the integument is a proper 

 lorica, closed and vase-like, is undeniable ; yet it is so thin and flexible that the head 

 retracted every instant carries with it the in-turned delicate front edge, which is again 

 everted. At the moment of eversion I have repeatedly seen what I believe to be an an- 

 tennal seta of exceeding tenuity ; but certainly no tubule or pimple. P.H.G. ] 



The lorica is tolerably flat on the ventral surface, but on the dorsal is distinctly 

 gibbous behind and depressed in front. Like that of Brachionus, it deepens down to the 

 hinder third of its length, and then suddenly drops with two abrupt curves. Viewed 

 dorsally (fig. 4), it can be seen that a central portion of the lower third is arched above 

 the general surface, and kept so bent by transverse muscular fibres. The head on the ven- 

 tral surface is scooped into a hollow above the buccal funnel, and the corona bears two 

 hemispherical ciliated prominences. On the long oesophagus, at a little distance from 

 the stomach, are two small stalked glands (fig. 4a) similar to those in Ptcrodina and 

 other Rotifera. The gastric glands are of unusual size and form. They are Y-shaped 

 (fig. 4), and each has its stem attached to the top of the stomach, and its outer branch 

 continued up to, and round, the inner dorsal surface of the lorica, to which it is attached. 

 Each inner branch hangs down, pointing inwards, towards the ventral surface, to which 

 it is probably tied by a fine fibre. These glands are distinctly, though delicately, 

 spotted with nuclei. The vascular system is best seen from the ventral surface (fig. 46), 

 where the lateral canals, surrounded by wide ribbons of delicate floccose matter, seem 

 to adhere to a considerable portion of the lorica, keeping chiefly toward the sides. The 

 contractile vesicle (fig. 46) looks as if it consisted of an oval central chamber, surrounded 

 by several smaller : an appearance probably due to the muscular fibres crossing it in a 

 somewhat regular pattern. It is rather large, and a side view (fig. 4a) shows that it 

 lies by itself at the hind end of the inner ventral surface, while the rest of the viscera 



