North American Freali-water Ostracoda. 433 



Palps (Fig. 4 and 5) of second maxillce in the male 

 hook-like, the right one larger than the left. 



Terminal claw of first foot rather stout, toothed, much 

 bent at tip, and as long as the last three segments. 



Terminal segment of second foot (Fig. 6) three fifths 

 as long as the preceding segment. The longer of the 

 backwardly directed setae is longer than the combined 

 lengths of the last three segments, the shorter one being- 

 one fourth as long, or the length of the last segment ; 

 terminal claw half as long as the last segment. Penulti- 

 mate segment three and a half times as long as broad 

 and armed on the inner edge with but one seta, which is 

 on the middle of the segment, and half its length. In 

 C. globom and C. Icevis there are two such setae. 



Caudal rami (Fig. 7) rather short, stout, somewhat bent, 

 the terminal claw half as long as the anterior edge, the 

 subterminal claw four fifths as long as the terminal claw, 

 both stout, lightly toothed, and strongh^ bent at tip. Ter- 

 minal seta about as long as width of ramus ; dorsal seta 

 delicate, two and a half times width of ramus from sub- 

 terminal claw, and two thirds as long as ramus is wide. 



The "organ of Zenker" is about twice as long as 

 wide, resembling that of C. glohosa. 



Described from several male and female specimens in 

 the collection of the Illinois State Laboratory of Natural 

 History, from a pond in the woods near Bloomington, 

 111., April 5, 1879. 



Named for Prof. S. A. Forbes. 



III. Cyprinotus Brady. 



1792. Cyprifi, 0. F. Miiller (49, p. 48). 

 1820. Monoculus, Jurine (3C>, p. 170). 

 1885. Cyprinotus, Brady (8, p. 301). 



Natatory setae of antennae reaching considerably be- 

 yond the tips of the terminal claws; plumose. Seta of 

 dorsal €'dge of caudal ramus close to subterminal claw; 

 claws smooth. Margins of right valve of shell generally 

 armed with tuberculiform teeth. Propagation sexual. 

 28- 



