A new species of Coelastrum 235 
round, are very often angular. The cells that show this “rounded 
angularity” are quite symmetrical, triangular in optical section, with 
a suggestion of three other intervening angles, thus appearing faintly 
hexagonal (Fig. v)—like the transverse section of the ovary of Viola. 
When the cells are spherical the spaces between them are very 
small, much smaller than in other species of Coelastrum (even C. micro- 
porum Naeg.), and these spaces are triangular in form (Figs, vm 
and ix). 
FR. 
Figures of Coelastrum schizodermaticum (magnified about 900 times). 
I. Single cell showing slight departure from spherical shape. 
II. Single cell showing splitting membranes. 
III. A two-celled individual showing angularity of cells. 
IV. Thickening at angles, and formation of one cap. 
V. Colony of four cells. 
VI. Colony of four cells, one cap splitting off. 
VII. Showing splitting away of outer membrane. 
VIII. The same. 
IX. Colony of four cells all having lost caps. 
