THE AGE OF MAMMALS 



places as Australia and the Oceanic Islands. ... It 

 would seem that the original stock was of Eurasian 

 derivation, though the great theatre of the evolutionary 

 drama was soon transferred to North America, the 

 Eurasian, African, and South American horses which 

 appear from time to time being in all probability of 

 North American origin. The ultimate fate of the horses 

 in both North and South America was extinction, all 

 wild horses of our own time, including the asses and 

 zebras, being confined to Asia and Africa. The apparently 

 wild bands of the American western plains, and those 

 which roam over the pampas of South America, are the 

 descendants of domestic horses that have escaped from 

 human bondage, largely from the early Spanish ex- 

 plorers. 



The rhinoceroses of to-day, the one-horned Indian 

 variety and the two-horned African rhinoceros, were pre- 

 ceded by a whole regiment of rhinoceroses in the Tertiary 

 period. One such was dug out in Fleet Street during the 

 excavation for the Daily Chronicle office. This rhinoceros 

 had a hairy coat like the Mammoth which lived much 

 later, and in Siberia is found sometimes side by side with 

 the later quadruped. Many of the extinct rhinoceroses 

 had two horns like the African square-mouthed rhinoceros, 

 which is sometimes misleadingly called the white rhinoceros. 

 One great extinct beast, the Elasmotherium^ allied to 

 them, had a great horn carried on a huge boss in the 

 middle of its head instead of on the nose, while another 

 still huger animal called the Titanotherium and found in 

 North America had a pair of horns perched on either 



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