126 THEORY OF EVOLUTION 



In man the sex formula appears to be XX 

 for the female and XO for the male (fig. 60), 

 and since the relation is essentially the same as 

 that in Drosophila the chromosome explanation 



determination in /Han. (ttitiifratter.) 



r 



FIG. 61. Spermatogenesis in man. There are 47 chromo- 

 somes (diploid) in the male. After reduction half of the 

 sperm carry 24 chromosomes (one of which is X) and half 

 carry 23 chromosomes (no X). 



is the same. According to von Winiwarter 

 there are 48 chromosomes in the female and 47 

 in the male (fig. 61). After the extrusion of 

 the polar bodies there are 24 chromosomes in the 

 egg. In the male at one of the two maturation 



