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.) 
Cyprinotus burlingtonensis Turner. 
PLATE LXX, Fias. 14-23. 
1894.— Cypris burlingtonensis C. H. Turner (215), pp. 17-19; Pl. VII, Figs. 14-23. 
1894.— ‘‘  burlingtonensis C. H. Turner (216). 
Length of the female 1.6mm. Width 0.89 mm. Height 0.93 mm. 
Length of the male 1.3mm. 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 five 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 sete extend to a short distance beyond the 
tip of the terminal claws. 
