COLOUR CHANGES IN COBNISH STOATS. 107 



restricted to Arctic tracts, where short summers were followed by 

 rigorous winters, in the extended peregrinations of these 

 animals they settled in warmer and still warmer areas till they 

 overran Europe and found a home in Northern India. In some 

 of these regions the colour change is useless, but though 

 apparently forgotten, the power to alter the dress is not lost, but 

 latent, two conditions — coldness and snow — being requisite to 

 induce its display. 



In the blizzard of March, 1891, we had in Cornwall the 

 essentials necessary to influence this power, intense cold and an 

 Arctic outlook. Hence, probably, in the Stoat before us, dormant 

 ancestral characters pointing to the derivation of the animal 

 from northern forms, are made visible, in a fur of singular 

 whiteness and beauty. 



