108 The Ohio Journal of Science [Vol. XX, No. 4, 



Phacus pyrum Ehrenberg. 



This organism was common among algae scraped from a 

 submerged stone (Station G) which had been taken early in 

 December and left standing in the laboratory for two months. 



Length 48^- 



Cryptoglena pigra Ehrenberg. 



This minute, active species was abundant in the same 

 material which contained the preceding form. 

 Length 15/x; breadth 9/i. 



Family Peranemidce. 



Peranema trichophorum. Ehrenberg. 



This form was infrequent in newly collected algae from the 

 bowl of the spring (Station J) and in floating Spirogyra from 

 Station C. It became very abundant however in a two weeks 

 old culture. 



Length 32-80m. 



Heteronema acus Ehrenberg-. 



Late in October one individual was taken in algae from 

 Station E. The cell was not perceptibly striated and the main 

 flagellum was as long as the animal, while the trailing one was 

 only half as long. 



Length 112^; width 32^. 



Anisonema acinus Du jar din. PI. Ill, Fig. 1. 



More than one individual of this species was never taken 

 in a collection. It was taken in floating Spirogyra (Station C), 

 on alga-covered poplar roots (Station D), and in algae from 

 Stations H, I and I', throughout the period of study. This 

 form is ordinarily described and figured with the nucleus 

 situated on the right side, opposite that on which the con- 

 tractile vacuole is located. In several individuals which the 

 writer observed (see PI. 3, Fig. 1), the nucleus was on the left 

 side, that is, on the same side with the contractile vacuole. 



Length 26-32/x; breadth 16/x. 



