820 



FRESH-WATER BIOLOGY 



8 1 (82) Terminal claws of furca not more than one-half as long as furca 

 (Fig. 1283 b) 83 



82 (81) Terminal claws of furca three-fifths as long as furca or longer (Fig. 

 1282 c) Cypria (Cypria) dentifera Sharpe 1897. 



Length 0.69 mm., height 0.38 

 mm., width 0.26 mm. Brownish 

 yellow, with dark brown markings 

 and reddish blotches. Right valve 

 overlaps left anteriorly. Left- 

 valve margins crenulate, anteriorly. 

 Natatory setae reach length of 

 antennae beyond tips of terminal 

 claws. Terminal short claws of 

 second leg approximately equal 

 and as long as the terminal seg- 

 ment. Furca stout, ten times as 

 long as wide, its subterminal claw 

 with a comb of remarkably long 

 teeth. Males common. Algae- 

 rich ponds. Illinois, Ohio, New 

 York, New Jersey. 



d 



Cypria (Cypria) dentifera. 



FIG. 1282. 



(a) Side view of left valve, X 30; (b) Dorsal view; (c) Furca; (d) End of 

 second leg. 



83 (84) Shell covered with a close reticulum of longitudinally subparallel 

 lines (Fig. 1283 c). Abdomen without processes. 



Cypria (Cypria) exsculpta Fischer 1855. 



Length 0.60 to 0.75 mm., height 

 0.38 to 0.42 mm., width 0.25 to 0.28 

 mm. Shell thin, covered with anasto- 

 mosing subparallel lines. Color clear 

 chestnut brown. Common in streams 

 and ponds everywhere. Also com- 

 mon in bottom tows in river chan- 

 nels, lake and river shores. Caudal 

 rami short, stout and much curved; 

 both terminal claws smooth; dorsal 

 setae situated slightly beyond middle 

 of ramus. Distribution world wide. 

 This species may be at once identi- 

 fied by means of the reticulum of 

 anastomosing subparallel lines on the 

 valves. These may be readily seen 

 with a two-thirds-inch objective. 



FIG. 1283. 



Cypria (Cypria) exsculpta. (a) Dorsal view, X 45; (b) Furca; (c) Striations on shell; (d) Spiny cylinder 



of ejaculatory duct, in sack. 



