Experimental Hybridizing as 
At one of the two. maturation divisions the united pairs of 
chromosomes separate again and move into opposite cells (Figs. 
rt and 1 A), so that one cell gets one and the other cell the other 
of each of the homologous chromosomes. Thus each cell will 
contain some paternal and some maternal chromosomes, but 
the number of the maternal may be different from the number 
I Ta I ie 
Ne Nz L—=—, bb 
; ( a 
on 
IN 
4 
BS: 
VA 
Fic. 6. Scheme to illustrate the two maturation divisions as seen in the 
spindle and chromosomes. The clear circles represent paternal chromosomes 
and the black dots the maternal chromosomes. In the first division, represented 
by I and I a, some of the maternal and some of the paternal chromosomes move 
toward each pole of the spindle. In the second division each paternal and each 
maternal chromosome divides into equal parts. In II the chromosomes of the 
cell derived from the upper end of I and Ia is represented; in IIa those from 
the lower end. 
of the paternal. At the other maturation division’ each chro- 
mosome divides equally Figs. II and II A, so that the daughter 
cells are exactly alike.* Thus there will be two cells of one kind 
in regard to the single character (or group of united characters) 
contained in’ each chromosome, and two cells of the other kind. 
The same process occurs both in the egg and in the sperm- 
cells. In the egg three of the cells, the three polar bodies, are 
1 In some species the first, in others, the second, is the equation division. 
? The meaning of this equation division has been much discussed, but nothing 
is known about it. 
