36 THE HORSE. 



rious parts of France and Germany. Another form 

 associated by Cuvier with PaLeeotheriuin, the first 

 known remains of which were found in the neigh- 

 borhood of Orleans and hence called P. aurelianense, 

 was by H. von Meyer separated generically tinder 

 the name of AncMtherium. It flourished in the Mio- 

 cene age, both in Europe and America, under many 

 minor modifications, and is generally looked upon 

 as in the direct line of ancestry of the modern 

 Equidce, which the true Palceotherium probably was 

 not. One of the most striking characters by which 

 it differs from Hyracotherium is the complete loss 

 of the fifth digit of the fore-foot, all the extremities 

 being alike in possessing only the three middle toes 

 (second, third, and fourth of the typical condition), 

 all reaching to the ground, but with the central one 

 (the third) longer than the others (see Fig. 4). The 

 two bones of the forearm (radius and ulna) and the 

 two of the leg (tibia and fibula) were still quite dis- 

 tinct. The pattern of the grinding surface of the 

 molar teeth (see Fig. 3, C, p. 31) had undergone some 

 further modifications from that of Hyracotherium, 

 which will be alluded to later on when describing the 

 dentition of the horse. The Anchitherium was suc- 

 ceeded in the Pliocene period, in America, Europe, 

 and Asia, by animals which have been named Hip- 

 parion, Hippotherium, Protohippus, and Pliohippus, of 



