CHAP. X. ] THE PALZZARCTIC REGION. 217 
extensive. The former is nearly 1,000 miles long, with a width 
of from 200 to 350 miles, and is almost as complete a desert as 
the Sahara. 
With very few exceptions, this vast territory is exposed to 
an extreme climate, inimical to animal life. All the lower parts | 
being situated to the north, have an excessively cold winter, so 
that the limit of constantly frozen ground descends below the 
parallel of 60° north latitude. To the south, the land is greatly 
elevated, and the climate extremely dry. In summer the heat 
is excessive, while the winter is almost as severe as further 
north. The whole country, too, is subject to violent storms, both 
in summer and winter; and the rich vegetation that clothes the 
steppes in spring, is soon parched up and replaced by dusty 
plains. Under these adverse influences we cannot expect 
animal life to be so abundant as in those sub-regions subject to 
more favourable physical conditions ; yet the country is so ex- 
tensive and so varied, that it does actually, as we shall see, possess 
a very considerable and interesting fauna. 
Mammalia—Four genera seem to be absolutely confined to 
this sub-region, Vectogale, a peculiar form of the mole family 
(Talpidee) ; Poephagus, the yak, or hairy bison of Thibet ; with 
Procapra and Pantholops, Thibetan antelopes. Some others 
more especially belong here, although they just enter Europe, as 
Saiga, the Tartarian antelope; Sminthus, a desert rat; and 
LEillobius, a burrowing mole-rat; while Myospalax, a curious 
rodent allied to the voles, is found only in the Altai mountains 
and North China ; and Moschus, the musk-deer, is almost confined 
to this sub-region. Among the characteristic animals of the 
extreme north, are Mustela, and Martes, including the ermine 
and sable; Guwlo, the glutton; Tarandus, the reindeer; Myodes, 
the lemming; with the lynx, arctic fox, and polar bear; and 
here, in the Post-pliocene epoch, ranged the hairy rhinoceros 
and Siberian mammoth, whose entire bodies still remain preserved 
in the ice-cliffs near the mouths of the great rivers. Farther 
south, species of wild cat, bear, wolf, deer, and pika (Lagomys) 
abound ; while in the mountains we find wild goats and sheep 
of several species, and in the plains and deserts wild harses 
Vou. L—16 
