THE CHROMOSOMES 163 
d and f. At the end of the process there are two 
chromosomes remaining in each of the four cells, e 
and g. 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 
Fic. 46.—Diagram to show the extrusion of the two polar bodies. 
Two tetrads are represented in a. The two succeeding divisions b-c, 
d-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 
cellis the polar body. At the first division the nucleus 
