ENTOMOSTRACA OF MINNESOTA. 333^ 



In the male there is a pair of verticillate sacs (Fig. 30). From the 

 distal extremity of each arises a vas deferens. Length of sac 0.35 mm. ; 

 width 0.11 mm. The copulative organ of male consists of distinct 

 halves, each half of which is composed of a large basal and a small 

 terminal portion. The basal portion of each division receives at its 

 proximal end a vas deferens. Length of copulative organ 0.37 mm.; 

 width 0.11 mm. 



Habitat: Small weedy ponds or canal basins. I have not found 

 these very often; but whenever found they were very abundant. On 

 one occasion I found a pool containing millions of males, but not a 

 single female. Specimens of this species have been found at Cincin- 

 nati, Ohio. (Turner, 213.) 



Cyprinotiis burlingtonensis Turner. 



Plate LXX, Figs. 14-23. 



18M.—Cypris burlirKjtonensis C. H. Tamer (215), pp. 17-19; Pi. VII, Figs. 14-23. 

 1894.— " burtingionensis C. H.TarueT {216). 



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. 17) the shell is sub oval, but the cephalic 

 extremity is wider than the caudal. The dorsal margin is convex, 

 the greatest convexity being nearer the cephalic than the caudal ex- 

 tremity. The cephalic and caudal margins are convex. The ventral 

 margin is nearly straight. 



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

 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. 



The antenna consists of fiv^e joints (Fig. 20), the fourth joint being 

 very long and slender. The distal joint is narrow, being no wider 

 than the base of the terminal claws. The terminal claws are slender 

 and the distal portion of each is fringed by a longitudinal row of very 

 fine teeth. The natatory setfe exteod to a short distance beyond the 

 tip of the terminal claws. 



