THE OSTRACODA 



8l 7 



61 (60) Shell reticulated, thin, the spermaries showing through. Equivalve. 



Cypris (Cyprinotus) crena Turner 1893. 



Shell equivalve from above, wedge-shaped anteriorly. 

 Hinge line sinuate. Length 1.14 to 1.23 mm., height 0.60 to 

 0.65 mm., width 0.59 to 0.60 mm. Yellowish green. Maxil- 

 lary spines smooth. Fourth segment of first leg not with four 

 extra short spines. Furca curved, about eighteen times as 

 long as wide. Males common. Abundant in small weedy 

 ponds and canal basins. Ohio. 



FIG. 1274. 

 Cypris (Cyprinotus) crena. (a) Side view, X 15; (b) Furca of male. 



62 (63) Furca normal, with two spines and two setae (Fig. 1278 d). 



Subgenus Cypris . . 64 



63 (62) Furca abnormal, the terminal seta missing (Fig. 1280 c). 



Paracypris New Subgenus . . 73 



64 (65) Both spines of first maxillary process smooth 66 



65 (64) Both spines of first maxillary process toothed (Fig. 12700). . . 68 



66 (67) Shell bluish black, with two yellowish areas in region of eye-spot 



(Fig. 1275 a) Cypris (Cypris} wrens Jurine 1820. 



Length 1.70 to 2.00 mm., height 0.90 to i.oo mm. Shell covered with short hairs, and 

 left valve slightly overlapping the right. Ventral edge flanged anteriorly. Natatory setae 

 reach to tips of terminal claws. Dark to yellowish green. Furca weakly S-shaped to straight 

 and from eighteen to twenty times as long as average width, and its dorsal margin smooth. 

 Very variable. Weedy ponds; April to July. Massachusetts, Mexico, Ohio, Wisconsin. 



67 (66) 



FIG. 1275. 

 Cypris (Cypris) mrens. (a) Side view, X 18; (6) Dorsal view; (c) Furca. 



Shell bright, deep green, smooth, with minute punctures. 



Cypris (Cypris) altissima Chambers 1877. 

 Length 0.80 mm., height 0.40 mm. Furca sinuous, its 

 two terminal claws nearly same length. Pond fed by melt- 

 ing snow, Mt. Elbert, Colorado. Altitude 12,000 feet. 

 FIG. 1276. Cypris (Cypris) altissima. Furca. 



63 (69) Terminal three segments of first leg longer than two- thirds of its 

 terminal claw (Fig. 1277 6) 70 



69 (68) Terminal three segments of first leg shorter than two-thirds of its 

 terminal claw 72 



