56 



PHYSICAL BASIS OF HEEEDITY 



of the female are conspicuously larger tlian the others 

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



Maturation Divisions of Protcnor Q 



Oocyte V Polar 5pmdk 2"' Polar Spile p„i,, ^'us 



Fia. 26. — Reduced chromoBome group; and extrusion of polar bodies in Prolenor. 



Maturation Divisions or Protenor cT 



,•&, 



^ 



t^^^m 



J'.' 



.00 jm 



1 



^o o 



^00 







//IK , 



n''ii 



Mdaphase oj the ^^j/^ 



1 *' Spcrmateyte ">\\*^ 



ATlapW6^ oJ tine hi.! 



P' Spermatocyte , ^ ^ , ^ %C^0O s. /^Q^. 

 MetaphsG oj the •4,/^'' (l*?^ 



2"^ Spermatocyte '*' 



Anaphase o| the 



2'^ Spermatocyte Sf^rmatozoa 



Fig. 27. — Reduced chromoBOme 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 



