vii DOMINANCE 71 



always be decided from the appearance of the bird 

 which bears them. 



There are cases in which an apparent irregularity 

 of dominance has been shown to depend upon 

 another character, as in the experiments with sheep 

 carried out by Professor Wood. In these experi- 

 ments two breeds were crossed, of which one, the 

 Dorset, is horned in both sexes, while the other, 

 the Suffolk, is without horns in either sex. Which- 



FIG. 15. 

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



ever way the cross was made the resulting F x 

 generation was similar ; the rams were horned, and 

 the ewes were hornless. In the F 2 generation raised 

 from these F 1 animals both horned and hornless 

 types appeared in both sexes but in very different pro- 

 portions. While the horned rams were about three 

 times as numerous 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 



