No. 395.] WORTH-AMERICAN INVERTEBRATES. 879 
AA. Last pair of legs directed downwards and used for locomotion. 
B. Mandibles slender and styliform. . . PARADOXOSTOMIDA* 
BB. Mandibles not styliform and toothed at the oe 
C. Second maxille pediform 
D. Caudal rami shaidhats, forming two rounded, setifer- 
. CYTHERID (IT) 
DD. Caudal rami well docsloned but small. BARDIIDA* 
CC. Second maxille not S but provided with a pediform 
DAD. -oi era . DARWINULID& (III) 
I. FAM. CYPRIDIDÆ. 
A. Second foot terminates with a cylindrical joint that bears two back- 
wardly directed setæ. 
B. Second foot of both male and female six-jointed. No branchial 
plate attached to the second maxillæ . . Notodromas 11 
BB. Second foot of the female usually five-jointed and of the male 
six-jointed. The second maxilla bears a branchial plate. 
C. Branchial plate feebly developed in the form of two pec- 
D: Bye prente c ee oa o e GRONA I 
DD. Eyeabsent . . Typhlocypris 15 
CC. Branchial plate dea in ii fori of three pectinated | 
setz . Candonopsis 2 
CCC. Branchial ea ERSE in ‘the fam of six pectinated 
setæ. 
D. Palp of second maxilla rudimentary 
Ilyocypris 10 
DD. Palp of second maxilla normally developed. 
E. Terminal joint of the second foot one third as 
long as the fourth joint or shorter 
Cypria 4 
EE. Terminal joint of the jerona foot two thirds as 
long as the fourth joint Cyclocypris 3 
AA. Second foot terminates with a beak-shaped foin ‘that bears one 
C. Flagellum-like . . . + Cypridopsis 6 
CC. With lamellar base a iiig seta. Potamocypris 12 
BB. Caudal rami normally developed, cylindrical, terminating in two * 
claws. 
C. Natatory setæ of the second antennæ not reaching to the 
base of the terminal claws . .  . . . Scottia 13 
