Nature of Sexual Diversity 



117 



nu.- 



Figure 32. The active and passive portions of cell and nucleus in 

 the egg of the whitefish. A. Egg just before division; with centrosome 

 (c), aster (a), nucleus (nu.) and cytoplasm (cy.). A set of radiations 

 have been formed about the aster as a center, indicating great activity. 

 B. Later stage; the aster has begun to divide into two. C. Still later; 

 the aster has separated into two with the nucleus between them. The 

 activities of the asters have begun to invade the nucleus. D. The 

 .nucleus has been transformed by the activities of the asters into a 

 spindle-like body, with the small chromosomes (chr.) ranged across its 

 middle. 



These two kinds of material, with their contrasted ways 

 of behaving, are held by many to form the basis for maleness 

 and femaleness, so that sex diversity is coextensive with life, 



