56 



PHYSICAL BASIS OF HEREDITY 



of the female are conspicuously larger than the others 

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



Maturation Divisions ot Protcnor Q 



m I 



Oocyte ?' Polar 5pindlc 



Mature E^^ and 

 Polav Bodies 

 Fig. 25. — Reduced chromosome group; and extrusion of polar bodies in Protenor. 



2-^ Polar 5piadl« 



Maturation Divisi 



KROTEt 



c; 



«l 'l ll , 



o? 







00^ 



ia5<5S 



Mctaphase oj the \\^j^ 



1 ^' Spermatocyte ^^V*" 



AnapWse o| the 

 P* Spermatocyte 



^00 



,0o 

 o o 







I 



# 



Metapkse oj the ^ -^\,/^ ' "* «c 

 2^^ Spermatocyte '"' 



Atiaphase o{ the 



ot,3 c . . Spermatozoa 



2" Spermatocyte ^ 



FiQ. 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 



