8i6 



FRESH-WATER BIOLOGY 



57 (56) Right-shell margins unusally tuberculate, as in Fig. 12716. Shell 



not more than one-half as high as long (Fig. 1271 a). 



Cypris (Cyprinotus) dentata Sharpe 1910. 

 Shell brownish yellow 

 and translucent in alco- 

 hol . Length i .3 5 to i . 60 

 mm., and height not more 

 than one-half as great. 

 Shell pointed posteriorly, 

 and anterior half of ven- 

 tral margin slightly sinu- 

 atein the male, but nearly 

 straight with the female. 

 Natatory setae reaching 

 well beyond the terminal 

 claws. Males common. 

 Furca gently curved, 

 about sixteen times as 

 long as wide. Spines of 

 first maxillary process 

 toothed. Temporary 

 ponds. Stamford, Ne- 

 braska. 



FIG. 1271. 



Cypris (Cyprinotus) dentata. 

 (a) Left shell from within, X 30; (6) Right shell from within, X 30; (c) Furca, X 105. 



58 (59) Dorsal seta of furca less than width of furca from subterminal claw 



(Fig. 1272 c). . Cypris (Cyprinotus}burlingtonensis Turner 1 894. 



Length 1.50 mm., height 0.70 mm., width 0.70 mm. 

 Yellowish brown with bluish black longitudinal 

 stripes on dorsum and sides. Hairy. Natatory setae 

 extend slightly beyond tips of terminal claws. 

 Maxillary spines toothed . Furca slender and straight, 

 about eighteen times as long as wide. Dorsal seta 

 close to subterminal claw. Shallow, temporary, grassy 

 pools. Ohio, Georgia, Delaware. 



FIG. 1272. 



Cypris (Cyprinotus) burlingtonensis. (a) Side view, X 16; 

 (b) Dorsal view; (c) Furca. 



59 (58) Dorsal seta of furca more than width of furca from subterminal 



claw 60 



60 (61) Shell with no markings, translucent. Right valve the larger. 



Cypris (Cyprinotus) americanus Cushman 1905. 

 Length 1.50 mm., breadth 0.70 mm., 

 height 0.80 mm. Colorless. Natatory 

 setae reach to tips of terminal claws. 

 Fourth segment of first leg with four 

 short extra spines. Terminal segment 

 of second leg constricted in the middle, 

 and with two longitudinal rows of 

 minute spines extending from the 

 constriction to the tip. Furca nearly 

 straight and about twenty times as 

 long as wide. Ponds and ditches. 

 Nantucket, Mass. 



FIG. 1273. 



Cypris (Cyprinotus) americanus. (a) Side 

 view, X 30; (b) Dorsal view; (c) Furca, 

 X 150; (d) End of first leg showing 

 extra spines, X 150. 



