420 INTRODUCTION TO ZOOLOGY. 



tracks are in a different quarter of the globe, for the greatest 

 number of species is found in Asia. 



VIII. (Ovis). " Sheep, the most ancient of our do- 

 mestic animals, may be traced originally to the countries of 

 Western Asia. They herd in flocks in a wild state on the 

 inaccessible mountainous districts of Asia, Europe, Africa, 

 and America." 



The elevation at which some of these creatures habitually 

 live is very remarkable, and to the zoologist a subject of 

 philosophic interest. The Chamois is found between the 

 upper limit of the trees, and the line of perpetual snow, which 

 in the Alps is 8,900 feet; and is 700 feet less on the northern 

 than on the southern declivities of these mountains. The Goat 

 of Cashmere browses on the comparatively naked table-lands 

 of Thibet, at a height of from 10,000 to 13,000 feet above 

 the level of the sea. The Pamir Sheep or Rass (Ovis polii), 

 lives at the still greater height of 15,600 feet in the table- 

 land of Pamir, eastward of Bokhara; and the Burrhel (Ovis 

 lurrhel) inhabits the highest ridges of the Himalayan chain, 

 where it is described as "bounding lightly over the incrusted 

 snows, at an altitude where its human pursuers find it difficult 

 to breathe." 



Fig. 319. BISON. 



IX. (Bos). The present group may be represented by our 

 domestic Oxen, which have ever been associated with the 

 field labours and the domestic comforts of man. But the 

 species most celebrated, are probably the ferocious Buffalo of 

 Southern Africa, and the Bison (Fig. 319), which roams in 

 vast herds over the trackless prairies of America, 



