No. 541] INHERITANCE OF COLOR IN CATTLE 



(quite common). In eye color the white Shorthorn is 

 either blue or brown; the roan and red Shorthorns are 

 always brown eyed. The characteristic pigment areas 

 may, in domestic animals, become subjected to rigid selec- 

 tion, resulting in modified forms — as the white belt of the 

 Dutch belted cattle and the white head, neck and under- 

 line of the Hereford. Approximations to the former and 

 to the reciprocal of the latter modifications (not of the 

 species pattern) are commonly observed among Short- 

 horns. In general, however, color patterns are quite 

 characteristic of the species mid arc quite persistent. 

 Greatly modified patterns are seldom seen and, moreover, 

 the reciprocal coloration is never seen. 



Not only does the whitening process begin at definite 

 centers quite specific for each species, but it also seems 

 to be definitely progressive in tissues carrying pigment. 

 Thus, the whitening process begins in man with the skin, 

 extending to the hair, the iris, and finally the choroid. 

 Partial albinos often have blue eyes — the absence of the 

 iris pigment but the presence of the choroid. In the 

 guinea pig the hair and skin pigments generally seem to 

 disappear before those of the eye. Castle 16 reports a 

 guinea pig with anarea of red hair underlaid by a patch of 

 black skin, and observes that a white dog may have a 

 patch of pigmented skin somewhere under the hair coat. 

 Similar phenomena are found in all species having parti- 



