4-48 Illinois State Laboratory of Natural History. 



genus. Second pair of maxillae provided with a rudi- 

 mentary branchial plate, formed of two unequal pecti- 

 nate setsB attached directly to the basal portion of the 

 maxilla; palp two-segmented in the female, terminating 

 with three unequal pectinate bristles; palps of the male 

 unsegraented, different from those of the female and 

 from each other. 



Second pair of feet commonly five-segmented, becom- 

 ing six-segmented occasionally through division of the 

 fourth segment; terminal segment provided with two 

 backwardly directed unequal setae and one long for- 

 wardly directed seta. 



Caudal rami strong, each ending in two strong claws 

 and a short seta, dorsal seta of ramus commonly re- 

 mote from these. 



The males are commonly more abundant than the 

 females. The shell of the male is ordinarily larger and 

 of another form than that of the female. The members of 

 this genus are not swimmers, being destitute of nata- 

 tory setae. They commonly crawl on the bottom or 

 may burrow in the sand and mud. 



This genus numbers twenty-five species, of which nine 

 are known to occur in America. 



KEY TO SPECIES OF CANDONA. 



1 (7). Fourth segment of second foot divided (second 



foot therefore six-segmented). 



2 (3, 6). Shorter seta on last segment as long as last 



segment. C. rostrata Brady & Norman. 



3 (2, 6). Shorter seta on last segment of second foot 



two to three times as long as last segment. 



4 (5). Caudal rami approximately straight (PI. XLVI., 



Fig. 11) ; dorsal seta two and a half times width of 

 ramus from subterminal claw; claws evenly curved, 

 weakly pectinate, the terminal one half the length of 

 the ramus ; the subterminal one nine elevenths the 

 length of the terminal one. C. recticatjda n. sp. 



