9G THE KOTIFEEA. 



C. SULCATA, Gosse, sp. nov. 

 . (PI. XXIV. fig. 5.) 



[SP. CH. Lorica broadly ovate, much elevated ; anterior edges straight ; ventral 

 plate much smaller in outline than dorsal, both strongly fluted ; toes blade-shai^ed. 



The general form and appearance of this species may cause it to be easily confounded 

 with luna, especially when viewed from the side. The arched carapace comes to a sharp 

 edge all round, bending far-in abruptly ; then bending outward again with a like angle, 

 and coming to a like edge, to form the ventral plate. This, when seen sidewise (fig. 5a), 

 seems to be of the same dimensions as the dorsal ; but when seen direct from below it is 

 much less all round (fig. 5c), except in front, where the pectoral edge is parallel with the 

 occipital, both being transversely straight, but bounded, as usual, by two small lateral 

 points. Both surfaces are coarsely and deeply fluted ; the incised lines of the dorsal 

 passing round and beyond the inbent edge. The bulbous foot projects slightly through 

 an excavation in the dorsal plate's thickness : it is kidney-shaped; in its hollow the toes 

 are articulated. The lorica is, by the graving of its surface, rendered so opaque that the 

 internal organs are not easily defined. There is, however, a small but conspicuous 

 crimson eye in the occiput, and, by inference, a brain. The mastax is so large that, 

 when the head is withdrawn, it occupies fully one-third of the visible area, at the 

 middle of the lorica. Below this appears the ample stomach, dark with digesting food, 

 and (in the condition just named) pushed far up above the mastax on either side. 



This well-marked species I obtained in a number of examples, both alive and dead, 

 haunting aquatic moss, in water sent me by Dr. Collins from his historic pool at Sand- 

 hurst. For awhile I thought I had got hold of the Euchl. lynceus of Ehrenberg, but 

 examination of his text and figures forbade the identification. It is of the usual manners. 

 It often swims smoothly and swiftly, continuing the exercise for long periods without 

 rest, the toes usually carried behind, in mutual contact ; yet at intervals anchoring, re- 

 tracting the head and foot, and assuming still repose, broken, now and then, to sway 

 wildly in all directions, on its glued toes, as on a pivot, more E. luna. P.H.G.] 



Length. Extended, y-J- ff inch; of lorica, ^\^ inch; of toes, ^^ inch; width of lorica, 

 ? ^3 inch. Habitat. Pool at Sandhurst, Berks (P.H.G.) : uncommon. 



Genus DISTYLA, Eckstein. 



[GEN. CH. Lorica of the form of a long ellipse, open and membranous before, closed 

 behind, depressed, higher before than behind ; lateral inangulation feeble ; toes two ; 

 " selvage-like thickenings of the lorica around the foot." 



Herr Eckstein has described and figured two species of this genus, whose toes bear 

 the same relation to each other as those of C. luna and rusticula. The genus is closely 

 linked with the preceding ; yet the lengthened and flattened form, the habitual protrusion 

 of the head, and the more constant activity of the species distinguish it. Only one of Herr 

 Eckstein's species has occurred with us, but I add (doubtfully) another. P.H.G.] 



D. GISSENSIS, Eckstein. 



(PI. XXIV. fig. 8.) 

 Distyla Gisscnsis . . . Eckstein, Sieb. u. Koll. Zeits. xxxix. 1883, p. 383, pi. xxvii. 



[SP. CH. Lorica round behind, broadly truncate in front, with short lateral 

 points ; toes rod-shaped, thick, obscurely tic o- shouldered, claios small; brain simple. 



The outline is that of a narrow ellipse abruptly cut-off a little before the middle, so 

 that the lorica, at its truncate front edge, is scarcely diminished in width. It becomes, 



