NOTOMMATAD^E. 21 



This attractive little form has so much resemblance to N. lacinulata, that I have 

 doubted whether it is not a variety of that species. There are, however, divergencies, 

 important, if minute. It is very much rounder in all aspects ; the toes are longer, 

 uniformly diminishing to acute points, and decidedly decurved ; no trace of eye could be 

 discerned. It swims rapidly, but evenly ; does not spring, and does not twitch ; both 

 which actions are so characteristic of lacinulata. Auricles (?) are occasionally pushed 

 out. The front projects in a tubercle, halfway between which and the auricle on each 

 side is a stiff seta. I have examined three specimens, two from Woolston, and one 

 from Dundee. 



Length, ^ inch. Habitat. Lacustrine. P.H.G.] 



NOTOMMATA THEODORA, GOSSC (171), (PL XXXI. fig. 8). 



[SP. CH. Eye small, quite frontal ; foot slender, straight, protrusile to an immense 

 length, or wholly retractile. 



A noble form, of great elegance, and of glassy clearness ; colourless, save for a tinge 

 of pale-orange in the tissues of the head (frequent in the kindred species), and the occa- 

 sional hue of the contents of the stomach. The body has the massive aspect of the 

 species named, but the position of the eye is notable, close to the frontal edge of an 

 ample brain. The form and extreme versatility of the foot, too, are quite peculiar. 

 Sometimes the body is truncate behind, and only the tips of the tiny toes are seen pro- 

 truding from the hyaline cavity ; when, with lightning suddenness, the foot, like a 

 slender rod of glass, is shot out to a length equalling the whole trunk ; and so carried, 

 while the animal darts along with headlong swiftness. The only parallel to this that 

 occurs to me, is the case of Rotifer macrurus. The toes are often turned suddenly, 

 to the right or left, at a joint just above them, the long foot else preserving its perfect 

 straightness. When smoothly swimming the front often appears as if auricles were 

 on the point of developing ; but I have not seen them extruded. In retraction the 

 front often becomes pursed-in in the middle. 



Length. When fully extended, about ^ inch. Habitat. Lacustrine. P.H.G.] 



NOTOMMATA POTAMIS, Gosse (170), (PI. XXXI. fig. 9). 



[SP. CH. Eo&ysiib-cylindric, gradually tapering to the foot ; brain clear, obscurely 

 three-lobed ; head broad, with conspicuous oblique auricles; trunk strongly fluted ; 

 foot long ; toes short, pointed. 



Having much in common with N. Naias, both in general form and in details, this 

 presents characters which appear to mark it as specifically distinct. In more than a 

 dozen examples which I have examined, alive and dead, from Woolston Pond and other 

 waters, these distinctive features were seen. The auricles are large and strongly 

 marked, extruded freely, and so remaining even in death, having the form, not of hemi- 

 spheres, but of short truncated columns, thrust out obliquely, so as to make the whole 

 head obconic. A great clear brain shows a tendency to triplicity ; the middle sac bears 

 a conspicuous red eye on its inner surface, above its swelling. The whole body is fluted 

 strongly, about twelve deep incisions running longitudinally throughout, so that a 

 transverse section would show so many rounded elevations. The stomach has a pair of 

 minute ovate glands, is very large and saccate, with a distinct intestine. The last joint 

 of the trunk forms a globose saccate sort of tail, over and behind the first joint of the 

 foot, not unlike that of Copeus pachyurus. The branchial system displays thick con- 

 volute vessels, and a small contractile bladder. The whole animal, in life, is often 

 tinged with delicate yellow, of deeper hue in the stomach. Several specimens, which 

 seem to belong to this species, recently obtained (April 1887) from a pond near my 

 residence, have the head of an orange hue, the front half of the mastax of a transparent 



