PLATE 5 



EXPLANATION OF FIGURES 



29, 30, 31 and 32 F 9 X C d" ; normally dividing cells from 12-hour stages. 



33 F 9 X C cf ; large cells with irregular nuclei from 12-hour stage. A few 

 normal cells are drawn for comparison (X 3.50). 



34 F 9 X C d^ ; abnormal cell from 12-hour stage. 



35 Fundulus sperm (X 2500). 



36 Ctenolabrus sperm (X 2500). 



520 



