ENTOMOSTRACA OF MINNESOTA. 295 
tory organs symmetrical, and of moderate size.’”’ (Brady and Norman. ) 
It is thought that the following modification of Wenzel Vavra’s 
key will serve to differentiate the genera. 
KEY TO THE FAMILY CYPRIDID&. 
I, The second foot terminates with a cylindrical joint that bears two 
backwardly directed sete. 
A. The second foot of the female and the male six-jointed. No 
branchial plate attached to the second maxille. Notodromas, 295 
B. The second foot of the female five-jointed and of the male 
six-jointed. The second maxilla bears a branchial plate. 
a. The branchial plate is feebly developed in the form of two 
pectinated bristles. 
* The eye isdeveloped. . : ; : ; Candona, 298 
** The eye is absent. 5 : *Typhlocypris. 
b. The branchial plate is developed in the ‘Giri of three pec- 
tinated bristles. ‘ : . *Candonopsis. 
ce. The branchial plate is in the fsoan of six : cpeatinatnd bristles. 
* The palp of the second maxilla is rudimentary. . *Ilyocypris. 
** The palp of the second maxilla is normally developed. 
{| The terminal joint of the second foot is as long as 
one-third of the fourth joint. ; ; ‘ Cypria, 304 
tt The terminal joint of the second foot is as long as 
two-thirds of the fourth joint. . 5 Cyclocypris, 310 
II. The second foot terminates in a beak-shaped joint that bears one 
backwardly directed claw. 
A. Caudal rami are rudimentary. ; : ; Cypridopsis, 312 
B. Caudal rami are cylindrical with two fenai nal claws. 
* Natatory sete of the antennz short. 
tT These setze not reaching to the tips of the terminal claws. 
Erpetocypris, 315 
tt These setz not reaching to the base of the terminal claws. *Scottia. 
** Natatory sete of the antenne long, reaching to or beyond 
the tips of the terminal claws. 3 
{+ Parthenogenetic. . i P : ‘ : : Cypris, 319 
tt Sexual. : : : : : Y : Cyprinotus, 329 
(*Not noticed in the text. ) 
In the above table an attempt has been made to tabulate all known 
freshwater genera of the Cypridide.. The genus Stenocypris Sars has 
been omitted because the data at my disposal do not seem to warrant 
its separation from the genus Hrpetocypris Brady and Norman. Of 
the twelve genera here mentioned, nine have been found in America. 
GENUS NOTODROMAS Lilljeborg. 1853. 
In shape the shell of the male is quite different from that of the 
female. 
The antennules are seven jointed. 
