Fresh-water Entomostraca of South America. 85 



more essential characters, agrees rather well with that of Kurz, 

 though easily distinguishable from it, I have felt justified in 

 establishing the new genus here proposed, for the reception 

 of these 2 species. Both species have been reared from 

 Brazilian mud, and will be described below. 



43. Psendalona latissima (Kurz). 



(Pl. XH, figs. 2, a— b). 



Alonopsis latissima, Kurz, Dodekas neuer Cladoceren. Sitzb. Akad. 

 AViss. Wien 1874, p. 40, PJ. II, figs. 13—15. 



Specific Characters. — Female. Carapace, 

 seen laterally, broadly quadrangular in form, height and length 

 about equal, dorsal margin more or less arched, ventral 

 somewhat bulging in front and almost straight in the middle, 

 posterior extremity but slightly narrowed, and transversely 

 truncated at the end, upper corner well marked, lower rounded 

 off. Head somewhat procumbent, slightly convex above, 

 rostral projection of moderate length and scarcely curved. 

 Surface of shell distinctly sculptured with rather conspicuous 

 longitudinal lines, which in the anterior part of the valves 

 are cut off by about 8 very strongly marked curved trans- 

 verse striæ, lower edges finely ciliated in the middle. Eye 

 of moderate size; ocellus somewhat smaller and located a 

 little nearer to the eye than to the tip of the rostrum. Anten- 

 nulæ narrow and elongated, extending about to the tip of the 

 rostrum. Lip-plate rather large, with the lower edge evenly 

 curved. Caudal part narrow, linear in form, straight, slightly 

 tapering distally, anal sinus very slight, lower corner scarcely 

 prominent, angular, marginal denticles rather small, numbering 

 about 12 in each row, lateral denticles very delicate, caudal 

 claws finely denticulate in their proximal half, basal denticle 



