UNICELLULAR PLANTS 



105 



different in appearance from the resting form. The chief 

 structural difference is the presence of two definite flagella 

 originating from basal granules in the cell protoplasm and ex- 



FIG. 41. Sphaerella lacustris. Various stages in vegetative life and spore for- 

 mation. (From Hazen.) 



tending through the coating of cellulose to the outside where 

 their undulations in the water lead to energetic and nervous 

 movements of the entire organism. A red so-called "eye- 



