8o8 



FRESH-WATER BIOLOGY 



15 (14) Shell rather narrow from above, compressed (Fig. 1254 J). Second 

 antenna four-segmented. . . Potamocypris Brady 1870. 

 Only one species in North America. 



Potamocypris smaragdina (Vavra) 1891. 



Length 0.65 mm. Shell grass green, nearly 

 crescent-shaped, and thickly covered with long, 

 closely appressed hairs. Pools and ditches, July, 

 August, and September. Eggs venniUon red. 

 Ponds and ditches, April, July, August. South 

 Chicago, Mexico. 



Fig. 1254. 



Potamocypris smaragdina. (a) Side view, X'40; 



(6) Dorsal view; (c) Furca, X 150. 



16 (17) With two distinct eyes (Fig. 1255 5) 18 



17(16) With eyes fused, ornone apparent (Fig. 1258 c) 22 



18 (19) First maxillary process with six spines. Furca with three long setae 

 and no spines (Fig. 1255 c-d). . .... 20 



19 (18) First maxillary process with six spines. Furca with four long setae 

 and no spines (Fig. 1256 c). 21 



20 Second antenna six-segmented in both sexes. Second leg terminat- 



ing in three setae, one of which is reflexed. 



Notodromas LiUjeborg 1853. 

 Only one species in North America. 



Notodromas monacha (O. F. Muller) 1785. 



Length 1.18 mm. "Hump- 

 backed"; brownish yellow. 

 Active swimmers, resembling 

 the Cladocera in many move- 

 ments. Occasionally hang to 

 surface film of water, back 

 down, as Cyprois. Permanent 

 fresh ponds with algae. North- 

 ern Indiana, spring and sum- 

 mer. 



Fig. I2SS. 

 Notodromas monacha. (o) Side 

 view of male, X 30_; (6) Dorsal 

 view, X ^o; (c) Maxillary spines, 

 X 100; W) Furca of female, X 

 60; (e) End of second leg, X no. 



