No. 562 ] 



COAT COLOR IN HORSES 



(32:; 



between bay and black, or is an example of the incomplete 

 dominance of the bay over the black. 



If this theory be true, such mahogany brown horses are 

 not, from the standpoint of reproduction, brown at all. 

 No true brown foals should come from them unless the 

 factor for brown be latent in their germ cells. They are 

 examples of the simplex bay and when mated should give 

 bay and black foals. 



When it is remembered that the records have all these 

 so-called mahogany browns recorded as browns, and no 

 possible way to separate them, it becomes a very difficult 

 matter to properly interpret results. I should be inclined 

 to agree with Sturtevant that no separation of brown and 

 bay can be made, were it not that I have found these two 

 classes recorded as brown, while one class is a brown and 

 the other class is a bay. Brown X brown matings, when 

 a per cent, of genetically bay individuals enter into such 

 matings, would have to give some bay foals. Twenty- 

 eight per cent, of bay foals is none too large to expect 

 from the number of simplex bays recorded as brown-. 



Another solution of this matter of black, bay and brown 

 was suggested by A. B. Cox in a letter to me under date 

 of May 14, 1912. 



Might it not be possible that bays, browns and blacks should be con- 



different shades ah 

 not divide the color 

 and black: (3) ch< 



may make the factors tor 

 >rm cells. For example, 

 are produced gray, bay, 



