30 



CHLOROPHYCEAE 



2.43 



3.1 7a.m. 



2.55a.m, 



2.40 a.m. 



Fig. 21. Volvox. A-I, stages in the development of the zoospore of V. Roiis- 

 seletii. A, zoospore just after escape. B, first division. F, preparation for 

 inversion. G— I, inversion. (All x 375.) J-O, stages in the inversion of a sperm 

 bundle of V. capensis. (All x 750.) (After Pocock.) 



