TWO FASHIONABLE FURS 215 
dark or light. Consequently, it seems a possible explana- 
tion of the phenomenon under consideration that the blue 
phase of the Arctic fox indicates a reversion to the 
ancestral coloration of the species, due to the fact that 
no advantage is to be gained by the assumption of a 
white livery. Such reversion might well take place only 
in certain individuals of a species, and would probably 
tend to become more or less completely hereditary. Before 
such an explanation can, however, be even tentatively 
accepted, it is necessary to ascertain whether the blue 
Arctic foxes of Iceland are in the habit of making winter 
stores of provisions. If they are not, but hunt their prey 
in winter, the theory will not hold good. 
For animals which hunt their prey in winter, or are 
themselves hunted, it would seem essential that they should 
be white even in the highest latitudes, where the long 
Polar night lasts three-quarters of the year, since in the 
bright starlight—to say nothing of moonlight—they would, 
if dark-coloured, be almost as conspicuous on the snow 
as in daylight. 
As regards the number of Arctic fox skins which find 
their way into the market, Mr. W. Poland, writing ten years 
ago, states that from twenty-five thousand to sixty thousand 
of the white phase were then annually imported from 
Siberia, the greater number of these coming to Leipsic. 
The fur of these is of a rather coarse quality, quite different 
from that of the fine-haired Greenland skins. In 1891 about 
nine thousand white skins were imported by the Hudson 
Bay and Alaska Companies, and nearly one thousand by 
the Royal Greenland Company. Of blue skins, about 
two thousand were annually imported into London by the 
Alaska Company, and some five hundred to Copenhagen 
by the Greenland Company, although in 1891 the number 
