394 OHIO BIOLOGICAL SURVEY 



L. 30? D. ? 



Distribution, North America. Found with Euyiotia pectinalis 



(Kiitz.). 



26. T. affinis Lemm. (Fig. 2, PI. XX). 



Cylindrical with undulations, with an extended neck like pro- 

 cess obliquely truncate, and with short but pronounced spike; 

 flagellum IV2 times length of body. 



L. 51/x. D. 27/.. 



Distribution, Europe. Standing water. 



Var. plamtonico Wolosz., has a rough shell, L.45/x D.25// while 

 var. levis Lemm. has a shell which is comparatively broad, L. 60/x. 

 68.5/x., D. 26-27/.. 



27. T. volgensis Lemm. (Fig. 3, PI. XX). 



Transversely oval with prominent neck, smooth; posterior 

 spike distinct ; flagellum slightly longer than body. 



L. 20-40/1. D. 15-20/i. 



Distribution, Europe. Plankton of the Volga. 



Var. treuhii Wolosz., has a rough shell, L.20-40/X, D.15-20/X, with 

 posterior spike 15-20/.. in length. Var. javanica similar to treuhii 

 but 25/i in length, 18-20/x in diameter and with a posterior spike 

 only bfx long. 



28. T. acuminata (Schmiarda), (Fig. 4, PL XX). 



Triangular or in the form of a trapezoid, smooth, distinctly 

 narrowed anteriorly with prominent straight or slightly curved 

 posterior spike ; collar obliquely truncate ; flagellum 2 times length 

 of body. 



L. 50-59/j. D. ? 



Distribution, Europe. In standing water. 



Var. verrucosa Teodor. has a shell with L.26-34/X and a D. 14-22/. 

 which is irregularly covered with spinous warts or protuberances. 



29. T. urceolata Stokes. (Fig. 5, PI. XX). 



Cylindrical with anterior neck like process transversely trun- 

 cate and a prominent posterior spike; flagellum about length of 

 body. 



L. A^iJi. D. ? 



Distribution, North America. Ponds. 



