Influence of Environment 



233 



ovary of a pure white animal. After recovery from the operation 

 this white female with the "black" ovary was bred to a pure white 

 male (Fig. 86). Three litters of offspring from these parents 

 were all pure black as shown in Figure 87. Although both parents 



FIG. 87. RESULTS OF CROSS DESCRIBED IN THE PRECEDING FIGURE. All 

 the offspring are black, though both parents are white, because the white 

 female contains only "black" eggs and black is dominant over white. 

 (From Castle.) 



