On Two New Members of the Volvocacese. 1 35 
The cell-membrane becomes swollen out into great blisters (Pig- 
15, A, B); the lobes of the chloroplast are widely divaricated 
(Fig. 15, D, G), and eventually the latter becomes a shapeless green 
mass (Fig. 15, C, E, H). 
Fig. 15. Pyramimonas delicatulus. Drawings to illustrate effects of weak 
solution of formalin. A-B, Cells beginning to blister; C, Completely 
spherical cell, chloroplast disintegrating, cilia swollen at extremities; D, 
Anterior axial view of same cell as C at earlier stage ; E, Posterior axial view, 
showing scattered starch grains of pyrenoid sheath ; F, Spherical cell, swollen 
cilia thrown off ; G, Oblique posterior axial view, showing lobes of chloro¬ 
plast ; H, Spherical cell, one cilia swollen, another twisted up (x 800). 
The pyrenoid disintegrates and the starch grains surrounding it 
are scattered (Fig. 15, C, E, F). The cilia swell at the tips (Fig. 15, 
C), or twist up (Fig. 15, H) and are often thrown off altogether (Fig. 
15, F). The cell-membrane finally becomes distended and spherical 
(Fig. 15, C) 1 and sometimes disintegrates. The process occupies 
1 Consult Teodoresco loc. cit., p. 219. Dimaliella is affected in a 
very similar way when the concentration of the saline water, 
in which it lives, is altered. 
