vii DOMINANCE 77 



the ewes were hornless. In the F 2 generation raised from 

 these FI animals both horned and hornless types ap- 

 peared in both sexes but in very different proportions. 



FIG. 15. 

 Fowls' feet. On the right a normal and on the left one with an extra toe. 



While the horned rams were about three times as nu- 

 merous as the hornless, this relation was reversed among 

 the females, in which the horned formed only about one- 

 quarter of the total. The simplest explanation of this 

 interesting case is to suppose that the dominance of the 

 horned character depends upon the sex of the animal 

 that it is dominant in the male but recessive in the 

 female. A pretty experiment was devised for putting 

 this view to the test. If it is true, equal numbers of 

 gametes with and without the horned factor must be 

 produced by the F 1 ewes, while the factor should be lack- 

 ing in all the gametes of the hornless F 2 rams. A horn- 



