180 



UNICELLULAE PLANTS. 



Fig. 93. — Protococcus (Pleurococcus) from the bark of an elm tree, in active vegeta- 

 tion and showing aggregation into masses of cells. A, Pleurococcus in the dried 

 condition. JB, Ascococcus (?), showing endogenous division into two cells and (Q 

 into four. D, E, F, motile forms of Protococcus (after Cohn). 



