138 HUNTING EXTINCT ANIMALS 



nor even with rodents, but are tiny hoofed animals, which 

 seem to have taken to eating either bark or twigs of the 

 bushes and trees; for they have developed the front teeth 

 until the upper ones are reduced to two having edges 

 like blades, while in the lower jaw there are but four so 

 arranged as to work against those in the upper jaw. In 

 front, then, these teeth look greatly like those of a rodent, 

 and the back teeth have been modified into permanently 

 growing grinders, like those of some of the advanced ro- 

 dents; so that the conclusion seems fair that these changes 

 are due to a change to food something like that of rodents, 

 and the result a development of this style of teeth. In 

 all other features, however, that is, the feet with their 

 hoofs, the arrangements of the bones even in the skull, etc., 

 the animal shows that it was descended from herbivors. 



Then there are litopternas, which are roughly like the 

 early horses in build with three toes on each foot, and simi- 

 lar teeth, but again it is a case of the surrounding having 

 impressed on a form the general shape which adapts it to 

 a given type of country, and not a case of relationship. 

 There are small species the size of a sheep, and others as 

 large as the modern horse. Our finest specimen consists 

 of a lower jaw, twelve vertebrae, and the two hind legs, 

 which, as this is the earliest member of this group, will add 

 greatly to our knowledge of the history of this group. It 

 is in many ways a fascinating group, for the later members 

 have completely paralleled the history of the horse, reducing 

 their toes through three to one on each foot, and develop- 

 ing the long slender limbs and long head of the horses. 



All these are herbivors or ungulates, and numerically 

 over half of our collection is made up of them. How- 

 ever, if the tiny rodents which occur in considerable num- 

 bers, though they really make up but a very small part of 

 the life of the area, are omitted, fully three fourths of all the 

 finds belong to the ungulates or hoofed animals. In the 

 number of different kinds the same seventy-five per cent. 



