6 



THE AMERICAN NATURALIST 



white chest, a white collar and generally a white tail tip. 

 With cattle of all breeds and crosses possessing broken 

 color patterns the process begins with a white belt at the 

 rear flank, continues with another at the fore flank, a 

 white underline and a white forehead. With horses of the 

 Knglish breeds it begins with a blaze face and white feet, 

 continuing with large body blotches. With the French 

 and the desert breeds it seems to begin with a "dappling" 

 of the body hair — dark pigment persisting longest on the 

 legs — and continues through a lighter "dappling" to 

 white, the skin remaining Mack, while t lie sharper whiten- 

 ing process seems to follow the sequence observed in Eng- 

 lish breeds. In the case of the piebald negro the median 

 face line is quite noticeable. Thus, while there is for each 

 species a characteristic pattern, there is in reality a some- 

 what common pattern in all species of mammals possessing 

 particolored individuals. This common pattern is de- 

 scribed as follows : White line down the face, white under- 

 line, white anterior belt or collar, white rear flank belt 

 and white feet and switch. These white areas may, in 

 animals possessing but little white, be represented by 

 several smaller areas, but always near the median line 

 of the areas white in the larger pattern, which smaller 

 areas may fuse as the pattern becomes coarser. Thus 

 the white nose and forehead in some cattle may in 

 others make a continuous white line down the face. 

 The white spreads from the areas just defined with much 

 the same sequence as a fire would spread over a "hide- 

 shaped" meadow, starting at the centers homologous 

 to the first white areas of the coat. In all cases the 

 pigments seem to persist the longest in and about the 

 eyes and ears and at the buttock — the "centrifugal 

 areas" mentioned by Castle. 



The coat of a white Shorthorn may consist of: (1) 

 Solid dominant white covering red (quite rare) ; (2) 

 some definite coat areas dominant white covering red, 

 others albinic white (very common) ; (3) some areas 

 albinic white, others dominant white not covering red 



