COLORATION AFFECTED BY THE ENVIRONMENT. 75 



intermediate stages are found. This view is not the one 

 generally accepted. It is, however, certain that this animal 

 does not invariably undergo a seasonal colour change ; and 

 there is a highly interesting connection between the capa- 

 bility of undergoing this change, and the habitat of the 

 individual. In its extreme northerly habitat, the Arctic fox 

 almost always, if not always, changes its bluish brown 

 summer dress for a pure white in the winter. The aspect of 



.\\.\ . - 



ir. 2. Ermine. 



the animal in the summer and winter dress may be gathered 

 from the woodcut on opposite page, and specimens may be 

 usuallv seen at the Zoological Gardens. 



V 



In Iceland, which is the most southerly area of the animal's 

 range, a change to white is the exception.* 



The Alpine hare illustrates the same principle : in Scandi- 

 navia it always becomes white in the winter ; in Scotland 

 this change generally occurs, but seldom in Ireland. So, too, 

 the stoat : it always becomes white in the Alpine districts of 



* Proc. Zool. Sue., 18G9, p. 228. 



