North American Fresh-vxiter Ostracoda. 431 



appendao'e. The second foot is five-segmented, terminat- 

 ing- in three setse, of which two are directed backward. 

 The two eyes are separate. The abdominal rami are 

 long and slender. 



Males are common. This genus numbers but one spe- 

 cies, which has been reported from Minnesota by Her- 

 rick (1885). I have never examined specimens. 



II. Cyclocypris Brady & Norman. 



1787-1854. Cypris, Auctorum. 



1820. Monoculus, Jurine (36, p. 179). 



1854. C/yprm, Zenker (75, p. 79). 



1889. (Jypria, Brady & Norman (9, p. 68) . 



1889. Cyclocypris, Brady & Norman (9, p. 70). 



I give below the description of this genus, partially as 

 amended by Vavra (68). 



The second pair of antennae are five-segmented in the 

 female, six-segmented in the male, the fourth segment 

 having no sense organ. Natatory setse very long, 

 reaching far beyond the tips of the terminal claws. The 

 palp of the mandible and of the first maxilla are but 

 normally developed. The second maxilla bears a branchi- 

 al plate and palp. In the male the right and left palps 

 are dissimilar, terminating as hooked prehensile organs. 



The last segment of the second foot is unusually long, 

 being two thirds the length of the fourth segment. The 

 caudal rami are strong, terminating in unusually strong- 

 claws and a delicate seta. The dorsal seta is situated 

 at some distance from the subterminal claw. 



Males are numerous. The copulatory organ is quad- 

 rangular. 



This genus differs from Cypria in the much more 

 plump shell, in the character of the second feet, in the 

 different form of the copulatoi-y organs, and in the ab- 

 sence of the two special sense organs on the second 

 pair of antenna? of the male. 



There are five species in this genus: C. glohosa Sars, 

 O. Icevis O. F. M., C. modesta Herrick, C. pusiUa Sars, 



