ENTOMOSTRACA OF MINNESOTA. 207 



These curious animals are often found at great depths in the larger 

 lakes, though they may also occur in weedy localities. They are poor 

 swimmers and rarely caught in the net. 



*Bosniina cormita Jurine. 

 Plate LXV, Figs. 3-5. 



Oval, almost spheroidal. Head high, concave below the eye. 

 Beak long, its flagellum midway between the eye and end of beak. 

 Eye large. Antennules curved like a hook composed of 10 or 11 seg- 

 ments. Antennae as long as the end of the antennules, three-jointed 

 ramus with five setsB, the four-jointed ramus with three sett©. Shell 

 high, greatest height in middle of the length. Back uniformly curved 

 and forming an obtuse angle, with the straight caudal margin. 

 Spines at the caudo- ventral angle short, turned dorsad. Shell hex- 

 agonally reticulate. Post abdomen short, truncate and excavated api- 

 cally, with two anal spines. Claws finely pectinate. Length 0.4 to 

 0.54 mm. 



* Bosiuiua longirosti'is O. F. Miiller. 



Plvtes XLV, Fig. 2; LXV, Fig. 2. 



General form oval, shell highest in the middle. Head high, beak 

 short, flagellum arising from near the end of the beak, front pro- 

 tuberant. Antennie longer than in B. cormita, three-jointed ramus 

 with five, four-jointed with four set*. Spines of shell short and 

 straight. Post-abdomen short, truncate, unarmed. Claws on a pro- 

 tuberance, pectinate. Length 0.31 to O.'JS mm. 



Bosiiiina loiigicornis Schoedler. 



Very similar to B. longirostris, but the front is not protuberant, the 

 flagellum is midway between eye and end of beak. The spines of 

 the shell are long, toothed ventrad and directed obliquely dorsad. 

 Shell unmarked. The finely pectinate claws have at their base sev- 

 eral large accessory spines. Length 0.36 mm. 



Bosiuiua brevicoruis Hellich. 



A large species with depressed head having a uniformly rounded 

 front. Shell higher than long and coarsely reticulate, spine short 

 and curved. The beak is short and little curved, the flagellum being 

 quite near the eye. The antennules have seven segments. The post- 

 abdomen is large without anal spines and the claws are simply pectin, 

 ate. Length 0.55 mm. Hellich says this differs from B. brevirostris 

 P. E. Mueller, which has a protuberant front and long serrate spine 

 and the claws have seven accessory spines. 



