chap, x.] THE PAL^ARCTIC 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 *auna. 



Mammalia. — Four genera seem to be absolutely confined to 

 this sub-region, Nectogak, a peculiar form of the mole family 

 (TalpidaB) ; 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 

 Ellobius, 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; Gulo, the glutton ; Tarandus, the reindeer; Myodcs, 

 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 horses 



Vol. L— 16 



