390 OHIO BIOLOGICAL SURVEY 



3. T. intermedia Dang. (Fig. 4, PI. XVIII) . 



Shell spherical, finely punctuate; flagellum opening with 

 annular thickening ; flagellum 2 times length of body. 

 L. 20/x. D. 16/x. 

 Distribution, Europe. 



4. T. verrucosa Stokes (Fig. 5, PI. XVIII). 



Shell spherical, colorless, emarginate anteriorly, covered with 

 wart-like processes; flagellum (?). 

 L. 24-24.5^. 

 Distribution, North America. Ponds. 



*5. T. rugulosa Stein (Fig. 6, PI. XVIII). 



Spherical with weak spiral folds; flagellum 2-3 times length 

 of body. 



L. 15-23^. 



Distribution, cosmopolitan. Standing water and Plankton; 

 Columbus Storage Dam. 



6. T. vermiculosa Palmer (Fig. 7, PI. XVIII). 



Spherical with short irregular folds; flagellum opening with 

 annular thickening. 



L. 23jU,. 



Distribution, North America (Palmer). Found accompany- 

 ing £'^t?^oim pecimaiis (Kutz.). 



7. T. stokesiana Palmer (Fig. 8, PI. XVIII) . 



Spherical with numerous longitudinal folds which often anas- 

 tomose and at the extremities become spiral ; flagellum opening a 

 short conical tube in a flattened depression. 



L. 18/x. 



Distribution, North America. Ponds Penn, Valley, Bucks 

 County (Palmer). 



8. T. spiculifera Palmer (Fig. 9, PI. XVIII) . 



Spherical with numerous short projections ; flagellum opening 

 with thickening either annular or in the form of a polygon. 



L. 25/x. 



Distribution, North America (Palmer). With Eunotia pecti- 

 nalis (Kutz.). 



9. T. vestita Palmer (Fig. 10, PI. XVIII). 



Spherical, thickly covered with radial spicules thickened on 



