130 



THE CHROMOSOMES 



d and /. At the end of the process there are two 

 chromosomes remaining in each of the four cells, e 

 and (J. Each cell becomes a spermatozoon. Here 

 as in most cases there is nothing to show whether 

 the first division is reductional and the second 

 equational, or the reverse. There is much divergence 

 of opinion on this point for different species. The end 



a 



d 



e 



f 



Fig. 46. — Diagram to show the extrusion of the two polar bodies. 

 Two tetrads are represented in a. The two succeeding divisions 6-c, 

 c?-e, show the separation of the members of the tetrads with the result 

 that one of each kind is left in the egg. 



result, however, is the same so far as the genetic 

 problem is concerned, the sequence being ordinarily 

 a matter of no significance. 



In the egg (Fig. 46) the process is identical with 

 that in the sperm, except that one of the two cells 

 formed is much smaller than the other. The small 

 cell is the polar body. At the first division the nucleus 



