THE OSTRACODA 



809 



vsj Second antenna five-segmented in both sexes. Second leg termi- 



nating in one claw and one reflexed seta (Fig. 1256 6). 



Cyprois Zenker 1854. 

 Only one species found in North America. 



Cyprois marginata Strauss 1821. 



Length 1.53 mm., breadth 0.7s 

 mm., height o,g6 mm. Uniformly 

 yellowish in color. An active, rest- 

 less swimmer, and ai times tries 

 hanging to the surface film of 

 water. Somewhat resembling N. 

 monacha in its swimming move- 

 ments. May also creep on bot- 

 tom debris. Grassy pools which 

 later dry up. Sexual. Furca stout, 

 slightly curved; dorsal seta uncom- 

 monly long. April to July. Chi- 

 cago, 111. (Jackson Park), April, 

 May, June. 



Fig. 1256. 

 Cyprois marginata. {a) Side view of 

 female, X 25; (6) End of second leg, 

 X 75: {c) Furca of female, X 60; 

 {d) Maxillary spines, X 75. 



22 (2.s) Natatory setae of the second antennae entirely lacking (Fig. 1298 c). 



Subfamily Candoninae . . 91 



23 (22) Natatory setae of the second antennae very evident, usually extend- 



ing at least to tips of terminal claws (Figs. 1268 e and 

 1290 c) 24 



24 (25) Terminal segment of second leg with three long setae and no claws, 



— one seta reflexed (Fig. 1258 b). 



Ilyocypris Brady and Norman 1889 . . 26 



25 (24) Terminal segment of second leg with at least one claw (Fig. 



12686), — ■ and usually beak-shaped 28 



26 (27) Shell with many prominent tubercles, knobs, and furrows. Nata- 



tory setae reaching to tips of terminal claws, or shghtly 

 beyond Ilyocypris gihba Ramdohr 1808. 



Length 0.85 to o.gs mm. Shell much tuberculate 

 anteriorly and posteriorly, and decidedly furrowed 

 anterodorsally. Two prominent tubercles just back 

 of the eye-spot. Poor swimmers. Furca nearly 

 straight, its terminal claws nearly equal in length, and 

 plain. Terminal seta of furca about two-fifths length 

 of terminal claw. Swampy regions, in mud, during 

 the spring months. In company with /. bradyi, usu- 

 ally. Colorado, March. 



Fig. 1257. 



Ilyocypris gibba. (o) Side view, X 45: 



{i) Dorial view, X 4S. 



