30 G. O. Sars. 
Surface of shell perfectly smooth, and but slightly hairy at 
each extremity; inner duplicatures narrow. Caudal rami of 
moderate size and somewhat curved, outer claw about half 
the length of the ramus. Posterior coil of spermatic vessels 
in male forming in the ventral part of each valve a remark- 
able bend in front. Colour of female light yellowish, with 
a dark brown patch above the insertion of the adductor 
muscle of the shell, generally drawn out behind into 2 
narrow bands, the lower one occurring just above the ceca 
of the intestine, the upper one near the dorsal face; ocular 
region more or less tinged with light chestnut. Colour 
of male darker brown. Length of female 1.9 mm., of male 
1.6 mm. 
Remarks.—I have only provisionally referred this 
form to the genus Cypris (sens. strict.); for in one character, 
at least, it seems to differ very markedly from the other 
species. Whereas all these, as far as I know, are partheno- 
genetic in character, the present species has turned out to 
be as pronouncedly gamogenetic as the species of the genus 
Cyprinotus. It cannot, however, by any means be referred 
to the latter genus, because the shell does not exhibit any 
of the characteristic features peculiar to that genus. In the 
narrow oblong shape of the shell it somewhat recalls the 
species of the genus Stenocypris; but the caudal rami do 
not agree in structure with those in the latter genus, the 
species of which, moreover, are pronouncedly parthenogenetic 
in character. 
Description of the female. 
The shell of the largest female specimen examined 
measures in length 1.9 mm, in height 0.8 mm., and in width 
