245 



maximum in some species of Glceocystis. Multiplication occurs 

 principally by a tetrahedric division of the mother-cells, accom- 

 panied by a gelatinization of the mother-cell-walls. Reproduction 

 also takes place by biciliated zoogonidia. 



Genus Gloeocystis Nag., 1849. [Chlorococcum Fries, 1825 (in 

 part).] The plants occur as small irregular colonies consisting of 





Fig. 113. A E, Gloeocystis infusionum (Schrank) W. & G. S. West, from Barnes 

 Common, Surrey. F H, Gl. gigas (Ktitz.) Lagerh., from Wimbledon Common, 

 Surrey. (All x420.) 



an indefinite group of cells formed by the successive division 

 of the mother-cells. The enveloping mucus generally shows a 



