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THE AMERICAN NATURALIST [Vol. XLVII 



I do not believe that either Wilson or Sturtevant is cor- 

 rect. I reached the conclusion in my first paper, based 

 on the records of the saddle horse alone, that brown is 

 dominant to chestnut and black and hypostatic to bay. 

 With all the figures before me now, I am still of the 

 opinion that brown is recessive to bay. When bay is 

 mated with brown the product is: 56 per cent, bay, :>2 per 

 cent, brown, 5 per cent, black and 7 per cent, chestnut. 

 The total number of horses produced by this mating is 

 2,460, a number large enough to show that the percentages 

 can be relied upon. Bay X bay produces : 77 per cent, 

 bay, 8 per cent, brown, 2 per cent, black and 13 per cent, 

 chestnut. 



Brown X brown gives : 2 per cent, chestnut, 11 per cent, 

 black, 59 per cent, brown and 28 per cent. bay. It is this 

 28 per cent, bay that is the greatest obstacle in the way 

 of the interpretation which I have given to the results. 

 If brown is a recessive to bay there should be no bay foals 

 from brown sire and brown dam. Yet such ma tings yield 

 a large per cent, of bay. I spent much time during the 

 summer of 1912 studying the color of horses in the field. 

 I believe that I have found an explanation for the above 

 difficulty. 



There is a brown horse that is called by horsemen the 

 seal brown. The seal-brown horses appear to be almost 

 black, and can easily be mistaken for black. The top line 

 is all black, as is the mane and tail. The legs, except for 

 possible white markings, are black up to the body. The 

 body is very dark brown, in some cases showing a lighter 

 shade near the flanks, and back of the nostrils a little of 

 the lighter shade of brown is found. This is the true 

 brown horse and only such should be recorded as brown. 



There is a class of so-called brown horses known as the 

 mahogany browns. These horses have black mane and 

 tail, black legs, the top line of the body and sometimes 

 the under line are black. The sides of the body have 

 many bay hairs mingled with the black hair. Some 

 blotches, usually near the flanks, seem to be exclusively 

 bay. It seems to me that this horse is on the border line 



