820 



FRESH-WATER BIOLOGY 



8i (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 o.6g 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 subtemninal claw 

 with a comb of remarkably long 

 teeth. Males common. Algae- 

 rich ponds. Illinois, Ohio, New 

 York, New Jersey. 



Fig. 1282. 

 (o) Side view of left valve, X 30; (6) Dorsal view; (c) Furca; (i) End of 

 second leg. 



Cypria {Cypria) dmtifera. 



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 0.7s mm., height 

 0.38 to 0.42 mm., width 0.2s 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 Unes on the 

 valves. These may be readily seen 

 with a two-thirds-inch objective. 



Fig. 1283. 



Cypria (.Cypria) exsculpta. (c) Dorsal view, X 4S; Q>) Furca; (c) Striations on shell; (d) Spiny cylinder 



of ejaculatory duct, in sack. 



