H^MATOCOCCUS 



that they travel a distance equal to 2^ times their own 

 diameter in one second. In swimming the pointed end is 

 always directed forwards and the forward movement is ac- 



i 



200 771-772 



FIG. 3. A. Hcematococcus pluvialis, motile phase. Living speci- 

 men, showing protoplasm with chromatophores (chr) and pyrenoids 

 (//r), cell-wall (c.w) connected to cell-body by protoplasmic filaments, 

 and flagellay?. The scale to the left applies to Figs. A D. 



B. Resting stage of the same, showing nucleus (mi) with nucleolus 

 (mi'}, and thick cell-wall (c.w) in contact with protoplasm. 



c. The same, showing division of the cell-body in the resting stage 

 into four daughter-cells. 



D. The same, showing the development of flagella and detached cell- 

 wall by the daughter-cells before their liberation from the inclosing 

 mother-cell-wall. 



E. Hcematococciis lacustris, showing nucleus (mi), single large 

 pyrenoid (//>'), and contractile vacuole (c.vac. ). 



F. Diagram illustrating the movement of a flagellum : ab, its base ; 

 c, c', c", different positions assumed by its apex. (E, after Biitschli. ) 



