310 



GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 



GENUS CYCLOCYPRIS Brady & Norman. 1889. 



This genus, founded by Brady and Norman (31), has been amended 

 by Wenzel Vavra (221). 



Antennules are seven-jointed. 



The antenme of the female are five-jointed; of the male, six-jointed. 

 There is no olfactory organ on the fourth joint. Natatory setse are 

 very long, reaching far beyond the tip of the terminal claws. The 

 palp of the mandible and of the first maxilla normally developed. 



The second maxilla bears a branchial plate and a palp. In the 

 female this palp is uujointed; in the male it forms a hooked prehensile 

 organ. 



The last joint of the second foot is unusually long, being two-thirds 

 as long as the fourth joint. 



Males are numerous. Zenker's organ is similar to that of Cypria. 

 The proximal side of its central cylinder is flat. Yas deferens is long 

 and convoluted. The copulative organ i« quadrangular. 



The abdominal ramus is robust, the caudal seta is situated at about 

 one-third the length of the caudal border of the ramus from its distal 

 extremity. 



Cyclocypris Isevis (O. F. Miiller.) 

 Plate LXX, Figs. 9-11. 



1785 



-Cypris hcvis Miiller (149), p. 52; PI. Ill, Figs. 7-9. 



1820.— 31onoculus ovum Jurine (98), p. 179; PI. XIX, Figs. 18, 19. 



18^5.— Cypris mimiki Baird (1), pp. 99; PI. Ill, Fig. 9. 



1837.— " brunnea Koch (102), H. X., Fig. 5. 



1837.— " lepidula Koch (102), H. X. 6. 



1850.— " minuia Baird (5), p. 155; PI. XVIII, Figs. 7 and 8. 



1851.— " pimiherina Fischer (64), p. 163; PI. XI, Figs. 6-8. 



1853.- " ovum Lilljeborg (118), p. 113; PI. X, Figs. 13-15. 



1868.— •' ovum Brady (18), p. 373; PI. XXIV, Figs. 31-34, 43-45; PI. XXXVI, 

 Hg. 8. 



1868.— " oiwm Claus (48), PI. I, Figs. 1-5. 



1874.— " ovum Brady, Crosskey & Robertson, (30), p. 125; PI. I, Figs. 29, 31. 



1888.— " ovum Schwarz (199), p. 18. 



1888.— " ovum Sostaric (202), p. 46. 



1889. — Cypria lasvis Brady and Norman (31), p. 69. 



1891.— " Ixvis Wenzel Vavra (221), pp. 68-71, Figs. 21, 211-21". 



1894.— " liBvis C. H. Turner (215), pp. 14, 15; PI. VII, Figs. 911. 



1894.— " Isevis C. H. Turner (216). 



Length 0.51 mm. to 0.57 mm. Width about 0.4 mm. 



The somewhat translucent shell is hispid and very tumid, being 

 about as broad as it is high. 



Viewed from above the shell is ovate with rounded extremities. 

 The eye, which is situated near the cephalic extremity of the animal,. 

 is easily seen through the shell. 



