THE EUGLENOIDINA OF OHIO 389 



J- Posterior end 



pointed . 44. T. obtusa 

 G^ Granulations present between 



spines . . . 45. T. horrida 



E- Form ovoid, the posterior or anterior 

 end broadest. 



Fi Posterior end broadest . 46. T. saccata 

 F- Anterior end broadest. 



G^ Posterior end rounded, and 

 only slightly narrower than 

 anterior end; collar notched 47. T. bulla 

 G- Posterior end becoming de- 

 cidedly narrowed ; collar not 

 notched ... 48. T. obovata 



D- Posterior end of shell produced into an 

 acute or spike like process. 

 E' Definite posterior spike like process 



absent; collar not toothed . 49. T. helvetica 

 E- Definite posterior spike like process 



present; collar toothed . . 50. T. caudata 



*1. T. volvocina Ehrenb. (Fig. 2, PI. XVIII) . 



Shell spherical, smooth ; flagellum opening with slightly thick- 

 ened margin, rarely with low collar; flagellum 2-3 times length 

 of body. 



L. 7-21^. 



Distribution, cosmopolitan. Standing water and Plankton. 



Three varieties are recognized, var. papillata Lemm., shell 

 spherical and flagellum opening surrounded by papilla ; var, cerri- 

 cula (Stokes), shell spherical with flagellum opening developed 

 into an internal tube 7-8/x in length; var. subglobosa Lemm., with 

 shell slightly elongate and flagellum opening developed into a short 

 internal tube. 



The water in small pools is at times colored a deep brown by 

 the large numbers of individuals of the species. 



Ohio, Lake Erie (Jennings) (Landacre), Gambler (Walton). 



2. T. perforata Awerinz. (Fig. 3, PI. XVIII). 



Shell spherical with minute openings ; flagellum opening with 

 annular thickening or with low collar. 

 L. 17-20/x. D. 16-19/z. 

 Distribution, Europe. Standing water and Plankton. 



