574 THE AMERICAN NATURALIST [Vol. L 



What color phases are is a matter aside from the 

 thread of the paper but the consideration of this case 

 has led so close to the interesting unsettled problem that 

 the writer hopes to be pardoned for calling attention to 

 certain things about them which he has noticed and 

 which seem to hold good pretty well. First, they are 

 limited to about four manifestations. The timber wolf, 

 Cants occidentalis we are told is gray, white, black, or red. 

 The gray squirrel (Sciunts ca rnlinci/sis) is gray or black. 

 The black bear (Ursus americanus) black (normal), 

 white (glacier bear) or red (cinnamon bear). The red 

 fox (Vulpes fulvus) gray (cross fox), black (silver fox) 

 or red (normal). The screech owl is gray or red. 



Students of heredity have shown that the normal gray 

 coat of a wild guinea pig is a composite of black, white 

 and red, which has been broken down by breeding into its 

 constituent parts so that we get black guineas, red 

 guineas, white guineas and guineas with the colors in 

 patches. The colors, you will notice, are the same as 

 those of the color phases occurring in nature and it 

 seems probable that color phases have come about by a 

 similar breaking down and reduction of the normal 

 colors in a species, and have definite limits beyond which 

 they are not likely to go. 



In conclusion one might go on indefinitely demonstrat- 

 ing the application of the rough classification of non- 

 adaptive variants proposed in our initial paragraph, 

 limited only by the number of forms one could call to 

 memory. Jf the significance of the classification has not 

 been exaggerated it is difficult to find another theory 

 which fits as well with the existing phenomena as the one 

 advanced of a centrifugal force, though it is a pure theory 

 and its acceptance a matter of individual taste. 



