46 THE HORSE. 



other. These are now represented by the three fami- 

 lies of the Tapirs, the Rhinoceroses, and the Horses. 

 Great as may be the differences between these ani- 

 mals as we see them now, we can trace their history 

 step by step, as shown by the fragments preserved 

 from former ages, farther and farther back into 

 time, their differences continually becoming less 

 marked, and ultimately blending together, if not 

 into one common ancestor, at all events into forms 

 so closely alike in all essentials that no reasonable 

 doubt can be held as to their common origin. 



As already indicated, the first named, the tapirs, 

 have retained much more of the original characters 

 of the primitive ungulates of the Eocene period than 

 either of the others, and have indeed remained prac- 

 tically unchanged since the Miocene period; while 

 almost all other mammalian forms which existed 

 then have either become extinct or undergone ex- 

 tensive modification. 



THE TAPIRS. (Family Tapiridce.) 



The tapirs constitute the single genus Tapirus, 

 of which all the known species are much alike in ex- 

 ternal as well as anatomical characters. They are 

 rather heavy, thick-set animals, with short and stout 

 limbs. The fore-feet have four distinct toes, the 

 first (that corresponding to the thumb of man) only 



