THE EVOLUTION OF THE HORSE. 
By W. D. Matruew, Ph.D., 
Associate Curator, Department of Vertebrate Palxontology. 
As a domestic animal the Horse is to be found almost every- 
where that man can live. He is spread all over the world — 
from torrid to arctic climates, in all the continents, in remote 
oceanic islands — he is completely cosmopolitan. But as a wild 
animal the Horse is at present limited to the Old World, and is 
found there only in the open arid or desert plains of Central Asia 
and Africa. There are two species in Asia, the Asiatic Wild Ass 
(Equus hemtonus), and the little known Przewalsky’s Horse (E. 
przewalskit), while in Africa there are the African Wild Ass (E. 
asinus) and the several species of Zebra (E. zebra, E. burchelli, 
E. quagga). In the Americas and Australia there are no true 
wild horses, the mustangs and broncos of the Western Plains and 
South America being feral (domesticated animals run wild) and 
descended from the horses brought over from Europe by the early 
white settlers. When the Spaniards first explored the New 
World they found no horses on either continent. The Indians 
were quite unfamiliar with them and at first regarded the strange 
animal which the newcomers rode with wonder and terror, 
like that of the ancient Romans when Pyrrhus and his Greeks 
brought elephants—‘‘the huge earth-shaking beast’’' —to fight 
against them. 
The Horse is distinguished from all other animals now living 
by the fact that he has but one toe on each foot. Comparison 
with other animals shows that this toe is the third or middle 
digit of the foot. The hoof corresponds to the nail of a man or 
the claw of a dog or cat, and is broadened out to afford a firm, 
strong support on which the whole weight of the animal rests. 
Behind the ‘‘cannon-bone.”’ of the foot are two slender little 
* Macaulay —‘' The Battle of Lake Regillus.”’ 
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