THEORY OF EVOLUTION 



77 



XX 



XX 



FIG. 38, A. Diagram illustrating inheritance of color blind- 

 ness in man; the iris of the color-blind eye is here black. 



XX 



XX X 



W V 

 IX-* "** 



X =FDIM ' 



XX 



FIG. 38, B. Reciprocal of cross in Fig. 38 a. 



barred. If these are inbred half of the daugh- 

 ters are black and half are barred all of the 

 sons are barred. The grandmother has trans- 

 mitted her color to half of her granddaughters 

 but to none of her grandsons. 



