56 



PHYSICAL BASIS OF HEEEDITY 



of the female are conspicuously larger than the others 

 (Fig. 25,^). When reduction takes place the sizes of 



Maturation Divisions or Protlnor Q 



I 



■<?(?> 





Mature Eg^ and 

 PoUy Bodies 



Fig. 26. — Reduced chromosome group; and extrusion of polar bodies in Protenor. 



Oocjte 



V' Polar 5pmdle 2'^ Polar 5piiidle 



Maturation Divisions or Protenor cf 





y./ 



^O o 





^ly^ " 



^.^ 



III ' 1 



Metaphase oj the X^i^ O^ ^ 



1 ^' Spermatocyte ~;.\\" ^^ r\ 



Anaphase o| the 



P' Spermatocyte m<^©0 



Metapbsc o| the -^\ //■ " 



2'^'^Sp£rmaloc)/!e '''^' 



Anaphase o( the 



ord Q . t Spermatozoa 

 / Spermatocyte ^ 



Fig. 27. — Reduced chromosome group of male; and spermatogenesis in Protenor. 



the fused pairs show that these two large chromosomes 

 must always unite with each other (Fig. 26). In the 

 male of certain species, as in Protenor (Fig. 27), the 



