468 llluiois State Laboratory of Natural History. 



curved, half as lonpj as the ramus, subterminal claw 

 two thirds as long as the terminal one, with a patch of 

 teeth near its tip. Terminal seta half as long as sub- 

 terminal claw ; dorsal seta slender, as long as width of 

 ramus, situated at middle of ramus. The inner edge of 

 the ramus was smooth in the specimens examined, thus 

 differing from Vavra's description (68, p. 63). 



Miim., 1883 (Herrick); Baxlej, Ga., 1895 (Turner); 

 Havana, lU. (Coll. 111. State Lab. Nat. Hist.). 



Xni. Cypridopsis Brady. 



CypHs, aiictorum. 



1820. Monoculus, Jurine (36). 

 1868. CypHdoiJsis, Brady (6, p. 375). 



Second pair of antennae five- segmented. Natatory setae 

 at end of third segment long and plumose. The branchia 

 of the second maxilla consists of a plate bearing five 

 plumose set£B or else of two setae which are inserted di- 

 rectly on the blade. 



Second foot five-segmented, with a strong chitinous 

 claw at its extremity. 



Caudal rami rudimentary, flagelliform, base turgid, a 

 short cilium on the dorsal edge. 



The males of this genus are unknown. There are 

 eleven species, of which three are known to occur in 

 America. 



KEY TO SPECIES OF CYPRIDOPSIS. 



1 (2). Branchia of second maxilla with five setae. Three 



dark bands on dorsal and lateral aspect of shell; very 



plump. Common. 



C. VIDUA (0. F. Miiller). 



2 (1). Branchia of second maxilla formed of two setae. 



3 (4). Caudal rami cylindrical, turgid at base, suddenly 



narrowing to a bristle which is little longer than 



the basal part. 



C. NEWTONi Brady & Robertson. 



4 (3). Caudal rami broad, gradually narrowing to a 



bristle. Shell much compressed. 



