92 VERTEBRATES I MAMMALS. 



in a wild state, except in those countries where horses 

 once in a state of domestication have been set at liberty, 

 as in Tartary and in America. Here they live in troops, 

 each of which is led by an old male. 



The varieties of the Horse are exceedingly numerous ; 

 but these varieties are all regarded as one species. The 

 Arab Horses are the most beautiful and the fleetest ; the 

 largest and strongest are from the coasts of the North 

 Sea; and the smallest from the North of Sweden and 

 from Corsica. 



In South Carolina are found the fossil remains of a 

 horse which was probably indigenous to this country. 



The Ass, E. asinus, Linn., is distinguished by its long 

 ears, and the tuft which terminates the tail. It is indige- 

 nous to the great deserts of Central Asia, where it still 

 exists in the wild state ; but, like the horse, it has been 

 domesticated, and is used for a beast of burden and for 

 draught in all parts of the world. It is noted for its 

 patience and great power of endurance. The hoarseness 

 of its bray depends upon two small cavities situated at 

 the bottom of the larynx. The Mule is the offspring of 

 this species and the horse. 



The Zebra, E. zebra, Linn., Southern Africa, has the 

 general form of the ass, and is regularly marked through- 

 out with black and white transverse stripes. 



The Dzigguetai, E. hemionus, Pall, is intermediate, in 

 size and appearance, between the horse and the ass. Its 

 home is the dry regions of Central Asia. 



The Quagga, E. quaccha, Gm., of Africa, resembles both 

 the horse and zebra, but differs from both in specific char- 

 acteristics. The neck and shoulders are brown striped 

 transversely with white, the rump reddish gray, and the 

 tail and legs whitish. Its voice resembles the barking 

 of a dog. 



The Onagga, E. montanus, Burchell, of Africa, is smaller 



