OF DENISON UNIVERSITY. I7 



The first foot is five-jointed, the third and fourth joints be- 

 ing distinct. The terminal claw is long and stout, longer than 

 the combined lengths of the last three joints. The second joint 

 is stout and about as long as the combined lengths of the next 

 two joints. 



The terminal claw of the second foot [fig. 43] is about 

 twice as long as the terminal joint. 



The feebly-curved post-abdomen [fig. 46] is stout and 

 short. The terminal claw is a little more than half as long as 

 the abdominal ramus. The adjacent claw is about three-fourths 

 as long as the terminal claw. 



Habitat : Cincinnati, Ohio. Abundant in the canal basins 

 and adjacent pools. 



Cypyis Biirlingtonensis, sp. n. 



[Plate VII, Figs. /^-2j.] 



Length of the female, 1.6 mm.; width, 0.89 mm.; height, 

 0.93 mm; length of the male, 1.3 mm.; width. 0.7 mm.; 

 height, 0.7 mm. 



The length of the shell is a little less than twice the width 

 and the height is about equal to the width. The shell is very- 

 thin and is covered with long hairs, [fig. 15]. The shell is also 

 marked with certain dark bands, which are due, in part at least, 

 to the internal organs shining through the translucent shell, 



Viewed from the side [fig. 1 7] the shell is sub-oval, but the 

 cephalic extremity is wider than the caudal. The dorsal mar- 

 gin is convex, the greatest convexity being nearer the cephalic 

 than the caudal extremity. The cephalic and caudal margins 

 are convex. The ventral margin is nearly straight. 



Viewed from above, the shell is sub-elliptical, the two ex- 

 tremities being more or less pointed [fig. 17] and of about equal 

 width. In some specimens the ends are round. The sides are 

 feebly convex, indeed in some parts they are almost straight 

 and nearly parallel. 



Viewed from the end the shell is nearly circular, the sides 

 being very convex. 



