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THE AMERICAN NATURALIST [Vol. XLVIII 



White buttock patches are present in several unrelated 

 ungulates — as the pronghorn (Antilocapra), the wapiti 

 (Cervus canadensis), and the Rocky Mountain sheep 

 (Ovis canadensis). Probably these are the result of 

 restriction or total inactivity' of the pigment patches 

 covering the rump. 



Among the deer family white is generally confined to 

 the under surfaces and the primary white breaks have not 

 been developed to form patterns. Albinistic deer are 

 fairly common, however, and in Fig. 42a I have made a 

 tracing from a photograph showing the side of a par- 

 tially albino doe in which areal restriction of pigment has 

 taken place in such wise that the primary patches are 

 all indicated, and separated from 'those of the opposite 

 half of the body by a median dorsal white line. The ear 

 and the neck patches are joined, but a few small islands 

 of pigment are left here and there, much as in cows. 



In the young of many deer and in the adult of such 

 species as the axis deer, a spotted pattern is developed. 



