THE CELL-DOCTRINE 







141 



Pi 



Fig. 19. Explanation of Mendelian Segregation in Terms of Germ-Cells. The 

 cases originally studied by Mendel were in the edible pea. The present 

 figure shows how the explanation which Mendel offered applies to the 

 color of the blue andalusian fowl. Compare with Fig. 20, showing the 

 modern extension of Mendel's explanation in terms of chromosomes. 

 See discussion in text. Squares represent adult individuals, circles ova 

 and spermatozoa. Pi, etc., as in previous Figs. 



