Gonyostomum semen ( Ehrenb. ) Diesing 1866, p. 332 

 PI. 99, Figs. 11, 12 

 Characters as described for the genus; cells 23-69/* in diameter, 

 36-92/x long; nucleus central; flagella as long as the cell body. 



Drouet and Cohen (1935, 1937) have made very critical obser- 

 vations on this organism and have described its morphology and 

 reproductive process. 



In swamps and acid ponds. Mich., Wis. 



[422 ] 



