150 THE BEHAVIOR OF UNIT 



Primary color-varieties 



of rabbits Constitutent factors 



u 



Gray A— C— B— E 



I 

 I 



U 



I 

 Black C— B— E 



I 

 I 



U 



I 

 Yellow A— C— B— R 



U 



I 

 Sooty C— B— R 



I 

 I 



If rabbits of various colors are turned loose 

 together in a warren, the population is likely to 

 revert more or less completely to the gray color- 

 ation of wild rabbits. The foregoing is in sub- 

 stance the statement of Darwin; and its correct- 

 ness is fully established. 



THE FACTOR HYPOTHESIS IN RABBIT 

 BREEDING 



Before going further it may be well to describe 

 the color varieties of rabbits. These are exceed- 



