ITS ANCESTORS AND RELATIONS 



33 



cene time in North America, to various modifications 

 of which the names Menodus, Titanothcrium, Megacerops, 

 Brontotherivm, and Symborodon have been given. They 

 were of gigantic size, with a large head, having on the 

 face a pair of stout, diverging, osseous protuberances, like 

 the horn-cores of ruminants. Their fore-feet had four 

 and their hind feet had three short stout toes. Also, 

 out of the line of descent of any existing Perissodactyles 

 was the remarkable Macrauchenia, a very specialised 

 form, which existed in South America, apparently to 

 Pliocene times, and then entirely disappeared from a 

 world in which the conditions necessary for its well- 

 being no longer existed, unless indeed we may sup- 

 pose that the life of a species, like that of an indi- 

 vidual, comes to an end by virtue of some inherent 

 tendency which is one of the essential attributes of its 

 existence. Leaving these and numerous other collateral 

 branches which have left no representatives, we may 

 pass to the third existing division, the most important 

 in regard to the present subject. 



Allied to Palseotherium, but probably more on the 

 direct line of descent between Hyracotherium and the 

 forms to be mentioned presently, was a small animal to 

 which the name of Palaplotherium has been given, of 

 which numerous teeth and bones have been found in the 

 beds of Upper Eocene age at Hordwell in Hampshire, in 

 the Isle of Wight, and in various parts of France and 



D 



