330 



BACKBONED ANIMALS. 



however, under the skin, that tell an interesting story in 

 the ancestry of the family.* The domestic horse (E. 

 cabalhis) came originally from the Old World, and is not 

 found now in the wild state except where it has been re- 

 leased by man, as the mustang of South America and the 

 muzir of Tartary. 



Ponies are dwarf horses, produced in cool countries, 

 as Shetland. The wild ass (E. onager) ranges in herds 

 from the Indies to Mesopotamia. They are distinguished 

 by long ears, the tail ending in a tuft. The hinny and 

 mule are hybrids of the ass (. asinus) and a horse. Four 

 species of zebra are known in Asia and Africa. They are 

 striped transversely with dark and white bands. The 

 voice of the quaggaof Africa resembles the bark of a dog. 

 The onagga of Africa is smaller than the ass. They are 

 dark bay with black stripes, the tail and legs being white. 

 The peculiar marking is protective. 



VALUE. Horses, mules, asses, etc., are the most valuable of do- 

 mestic animals ; almost every part of the animal is valued in trade. 



* Professors Marsh and Huxley, especially the former, have made 

 interesting discoveries concerning the fossil horse, and its ancestry is 

 more complete than that of any other animal. The remains are found 

 in the Tertiary beds of North America. The earliest horse was the 

 eohippus (Eocene time), as large as a fox. The following is the gene- 

 alogy of the horse : 



. In Front Hind No. of In 



America. Toes. Toes. Teeth. Europe. 



{Recent .... ) j x Equus. j 



U P p n er Pliocene . Equus f ^plmT s 2 splints ' Equus . f 



6. Upper Pliocene . . Pliohippus j-^ {.- 42 



i large i large 

 5. Lower Pliocene . . Protohippus r. ,r 44 Hippanon. 



4. Upper Miocene . . Miohippus 3 3 44 Anchitherium. 



3. Lower Miocene . . Mesohippus j \w\. ^ ^ 



2. Upper Eocsne . . Orohippus 4 3 44 



i. Lower Eocene . . Eohippus ~ 3 44 



