434 Illinois State Laboratory of Natural History. 



In other respects this genus does not differ materiallj 

 from the genus Cj'pris. 



The species thus far known in America are C. incongru- 

 ens Ilamd., C. crena Turner, C. hurlingtonensis Turner, 

 C. grandis (Chambers), and G. jpellucida n. sp. 



COMPARISON OF SPECIES. 



1 (4). Dorsal seta of caudal ramus more than half as 



long as subterminal claw. 



2 (3). Dorsal seta width of ramus from subterminal 



claw. C. PELLUCIDA U. Sp. 



3 (2). Dorsal seta two and a half times width of ramus 



from subterminal claw. C. incongruens Ramd. 



4 (1). Dorsal seta of caudal ramus less than half as 



long as subterminal claw, and width of ramus 

 from it; setae of ramus about equal in length, 

 the dorsal seta reaching beyond tip of ramus by half 

 its own length ; ramus faintly serrate. 



C. BURLiNGTONENsis Tumer, 



Cyprinotus pellucida n. sp. (PI. XLIL, Fig. 1-6.) 



A moderately large species, from 1.10 to 1.40 mm. 

 long, .80 mm. high, and .51 mm. wide, color var^-ing 

 from transparent to brownish yellow, commonly show- 

 ing the outline of the animal within, the contents of the 

 stomach and intestines being unusually apparent. Shell 

 sparsely covered with small papillar elevations from which 

 short hairs arise, these being longest at each extremity ; 

 also commonly well marked with a regular arrangement 

 of dotted lines (Fig. 3). 



Seen from the side (Fig. 1), the shell is nearly ellip- 

 tical, regularly arched dorsally, nearly straight ventrally» 

 anterior and posterior ends convex. 



Seen from above (Fig. 2), the shell resembles a pointed 

 ellipse, bluntly pointed posteriorly and rather acutely sa 

 anteriorly. 



The two longer of the natatory setae of the second an- 

 tenna? reach but slightly beyond the terminal claws. The 



