THE CELL-DOCTRINE 



143 



P i 



F, 



h 



Fig. 20. Explanation of Mendelian Segregation in Terms of Chromosomes. 

 The number of chromosomes is taken as four pairs in cells of adult body, 

 reduced to one member of each pair in the ova and spermatozoa. See 

 discussion in text. Squares and circles as in previous figure. 



