14 



FRESH-WATER BIOLOGY 



47 (46) Shell very tuberculate, sparsely hairy and unusually plump (Fig. 

 1267 c) S piracy pris tuberculata Shsiipe igoS. 



Length 0.93 mm., height 

 0.53 mm., width 0.70 mm. 

 Purplish brown, with one or 

 two dorsal transverse lighter 

 bands. Right valve sHghtly 

 overlaps the left anteriorly. 

 Natatory setae extend but 

 slightly beyond the ter- 

 minal claws. Furca about 

 thirty-two times as long as 

 wide. Shallow, weedy, and 

 swampy ponds; spring. 

 Chicago and northern In- 

 ^ diana. 



Fig. 1267. 

 Spirocypris tuberculata. (a) Side view, X 43; {b) Furca; (c) Dorsal view. 



48 (49) First leg four-segmented, third and fourth segments united 

 (Fig. 1268 c). . . Subgenus Eurycypris G. W. Miiller 1898. 

 Only one species in this subgenus. 



Cypris {Eurycypris) puhera O. F. Miiller 1785. 



Length 2.10 mm., height 

 1.25 mm., breadth 1.20 mm. 

 Greenish in color. A dark 

 patch at its highest and cen- 

 tral part as seen from the side. 

 Shell sparsely hairy. Anterior 

 and postero-ventral margins 

 with prominent external tuber- 

 cles. Two prominent tuber- 

 cles at postero-ventral part cf 

 shell. This character alone is 

 suflBcient to identify this species 

 of c>^pris. First leg four-seg- 

 mented. Furca nearly straight, 

 about twenty-four tinies as long 

 as wide. Ponds; April to June. 

 Oregon. 



Fig. 1268. 

 Cypris {Eurycypris) pubera. 



(a) Side view, X 10; 



(b) End of second leg; 



(c) First leg; 



(d) Furca; 



(e) Second antenna; 



(/) Posteroventral part of shell. 



49 (48) First leg plainly five-segmented (Fig. 1277 b), third and fourth seg- 



ments not united 50 



50 (51) Inner anterior edge of right shell thickly tuberculate (Fig. 1270 a). 



Subgenus Cyprinotus Brady 1885 . . 52 



