THEORY OF EVOLUTION 



97 



FIG. 49. In the upper row of the diagram a typical process 

 of nuclear division, such as takes place in the early germ cells 

 or in the body cells. In the lower row the separation of the 

 chromosomes that have paired. This sort of separation takes 

 place at one of the two reduction divisions. 



Then follow two rapid divisions (fig. 49 f, 

 g and 50 and 51) . At one of the divisions the 

 double chromosomes separate so that each re- 

 sulting cell comes to contain some maternal and 



