180 



UNICELLULAR PLANTS. 



FIG. 92. Protococcus (Pleiirococcus) from the bark of an elm tree, in active vegeta- 

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

 condition. _B, Ascococcus (?), showing endogenous division into two cells and (C) 

 into four. Z), , F, motile forms of Protococcus (after Conn). 



