THE CARRIERS OF THE HERITAGE 23 



geometric progression throughout subsequent genera- 

 tions. In 1883, too late for Darwin to learn of it, 

 van Beneden discovered the important fact that the 



Primordial Sex Cells 



Mani) similar cell divisions 



MATURATION 



Spermatocyte 1- OoqU 

 <-Spermalid5 2.-Oocijte- 



^ 



FIG. 14. Scheme to illustrate maturation of germ-cells. 

 j 



nature germ-cells, as expected, actually contain only 

 naif the normal number of chromosomes. 



'"lie mature egg- or sperm-cell, with half its normal 

 number of chromosomes, is termed a gamete (marry- 



