300 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 



Length 1.25 mm. Height 0.58 mm. Width 0.46 mm. 



The shell is smooth, white, and elongated. It is more than twice 

 as long as high and about three times as wide. 



Viewed from the side, the shell is sub-reniform, highest in the 

 middle. 



Viewed from above, the shell is sub elliptical with pointed extremi- 

 ties. The widest portion is in the middle. One valve is a trifle 

 longer than the other. 



The antennas are stout. The natatory setse are absent and the ter- 

 minal is long and non-pectinated. 



The post-abdomen (Fig. 34) is curved and slender. The terminal 

 claws are slender and pectinated. 



Habitat: San Antonio Eiver, Texas. I have seen only three speci- 

 mens of this species. They were collected for me by Mr. A. B. 

 Whitby. 



Caudona crogmani Turner. 



Plates LXXI, Figs. 24-33; LXXXI, Figs. 4-5. 



Candona crogmaniaria—C. H. Turner (215), p. 20; PI. VIII, Figs. 24-33. 



Length of female 1.52 mm. Height 0.76 mm. Width 0.58 mm. 



This form is about the size of the elongated variety of Candona Can- 

 dida. The two most obvious differences are: J, the inequivalve shell 

 with pointed extremities; 2, the second foot is six-jointed. 



The shell is very thin, so thin that the ova and sperm atozoids are 

 visible through it. It is glossy and is covered with short scattered 

 hairs. These hairs are more numerous around the margins than else- 

 where. In the living specimen the body shines through the pellucid 

 shell and gives it a greenish yellow tint. ISTumerous VorticelUdce are 

 usually found attached to the lorica. 



Viewed from the side (Fig. 33), the female is sub-triangular, the 

 caudal third being the highest portion. The caudal, dorsal and ceph- 

 alic margins are convex. The ventral margin is slightly sinuate, be- 

 ing concave in the middle. 



Viewed from above (Fig, 32), the shell is an elongated ellipse, 

 pointed at both ends. One valve is longer than the other and over- 

 laps it at each extremity. 



The antenna (Fig. 25) is five-pointed in the female. Near the 

 proximal end of the lower margin of the first joint there is one elon- 

 gated filament and one short, pectinated, dagger shaped filament. 

 The terminal claws are slender, non-pectinated and long — longer than 

 the combined lengths of the last three joints. The antenna of the 

 male is six-jointed. 



