ITT LECTURES ON EVOLUTION 125 



fact, Lartet and De Blainville called it Palceotherium 

 equinum or hippoides ; and De Christol, in 1847, 

 said that it differed from Hipparion in little more 

 than the characters of its teeth, and gave it the 

 name of Hipparitherium. Each foot possesses 

 three complete toes; while the lateral toes are 

 much larger in proportion to the middle toe 

 than in Hipparion, and doubtless rested on the 

 ground in ordinary locomotion. 



The ulna is complete and quite distinct from 

 the radius, though firmly united with the latter. 

 The fibula seems also to have been complete. 

 Its lower end, though intimately united with that 

 of the tibia, is clearly marked off from the latter 

 bone. 



There are forty-four teeth. The incisors have 

 no strong pit. The canines seem to have been 

 well developed in both sexes. The first of the 

 seven grinders, which, as I have said, is frequently 

 absent, and, when it does exist, is small in the 

 horse, is a good-sized and permanent tooth, while 

 the grinder which follows it is but little larger 

 than the hinder ones. The crowns of the grinders 

 are short, and though the fundamental pattern 

 of the horse -tooth is discernible, the front and 

 back ridges are less curved, the accessory pillars 

 are wanting, and the valleys, much shallower, are 

 not filled up with cement. 



Seven years ago, when I happened to be looking 

 critically into the bearing of palseontological facts 



