742 niuF. G. o. SAus ox [May 3, 



villosa, and acideata, and was characterized chiefly by the 

 imperfect development of the caudal rami. In the year 1896 

 Messrs. JJrady and Xormaii separated one of these species, viz. 

 C rklaa, from the other two under a new genus I'ioitocjjpris, to 

 which they also referred the Australian form descrihed l)y the 

 present author as Cj/pridop.sis i/lobidas. As pointed out by 

 Dr. Viivra, these two species, however, are not congeneric, 

 P. mdaa having the caudal rami rudimentary, whereas in the 

 Australian species they are normally developed, proving it to 

 belong to the genus Cypretta of Viivi-a. The genus Pionocypris 

 therefore must be restricted to P. vidua and allied European 

 s})ecies [helvetica, obesa, picta). I think we are Ijound to accept 

 the arrangement proposed by the British authors, according to 

 which the type oi the genus Cyprido'psis is not, as suggested by 

 Dr. Yiivra and Di'. Kaufman, (J. vidua, but C. villosa, which was 

 referred by ])r. Vjivra to the genus Candonella Claus, by 

 Dr. Kaufman to his genus Cypridopsella. 



A third genus, likewise with rudimentary caudal rami, but 

 Avith reduced natatory setfe on the inferior antenna?, was 

 established by Brady inider the name Potamocypris. Tlie genus 

 Paracypridopsis of Kaufman is in all probability identical with 

 that genus. We have thus three northern generic types, all 

 with rudimentary caudal rami, viz. Cypridopsis, Pionocyj)ris, and 

 Potamocypris, to which recently a fourth African type, Zono- 

 cypris, has been added by Dr. G. W. Miiller. Two species of the 

 last-named genus will be described in the sequel ; the other ten 

 species of the " Cypyidojjsis-gvowp " obtained by the Tanganyika 

 Expedition I provisionally i-efer to the genus Cypridopsis, as 

 restricted by Messrs. Brady and Norman. 



13. Cyphidopsis obliquata, sp. n. (Plate LXIX. figs. 1-10.) 



Specific Characters. — Female. Shell moderately tumid ; seen 

 laterally (fig. l)of oval triangular shape, greatest height occurring 

 a little behind the middle and exceeding half the length, both 

 extremities obliquely I'ounded and nearly equal, dorsal mai-gin 

 strongly arched in the middle, ventral nearly straight ; seen 

 dorsally (fig. 2) oblong-ovate in foiun, greatest width consiilerably 

 exceeding one-third of the length and occurring a little lieliind 

 the middle, anterior extremity narrower than posterior. Valves 

 rather pellucid and very conspicuously unequal, the left one being 

 much the larger and overlapping the right, not only anteriorly, but 

 also along the greater part of the dor.sal face, wherel)y the shell 

 assumes a peculiar oblique appearance *. Surface of shell smootli, 

 l)ut rather densely hairy at eiich extremity. Muscular impressions 

 in the centre of the valves (fig. 3) somewhat diftering in their 

 arrangement from tho.se in the genus Paracypria. Eye large and 

 conspicuous. Superior antennae (fig. 4) of normal structure. 

 Inferior antennae (fig. 5) rather coarsely built, with the apiail 



* It may hfre be noted that in C vi7/os«f, where a similar obliquity of the shell 

 otciir.s, it \s not the lett luit the right valve which i.- the larger. 



