The Cellular Basis 



141 



which continue during every cleavage of the egg, lead to the segre- 

 gation of different kinds of plasms in different parts of the egg 



FIG. 45. SUCCESSIVE STAGES IN THE CLEAVAGE OF THE EGG OF A MOLLUSK 

 (Crepidula), showing the separateness of the male and female chromo- 

 somes ($ch, 9-c/O and of the male and female halves of each nucleus 



