4 THE HORSE 



concerned; or Eocene (the first and lowest), Oligocene, 

 and Pliocene ; while on the Continent there is a 

 fourth, the Miocene, intermediate between the Oligocene 

 and Pliocene. Then comes the Pleistocene or Quater- 

 nary epoch, divided into three periods : No. 1, the 

 Upper, or Post-Glacial Pleistocene, the Age of the Rein- 

 deer, and the extremely artistic race known as the Eein- 

 deer Men ; No. 2, the Middle Pleistocene, or Last Glacial 

 Age, when another race existed known as the Neander 

 Men ; and lastly. No. 3, the Lower Pleistocene, when 

 man must have lived, as flint implements have been 

 found in the gravels of England and France, though 

 no human remains have yet been discovered. 



It was not until the Quaternary Period, millions of 

 years after the epoch of the early Hyracotherium, that 

 amongst its gravel and cave-deposits the weapons, imple- 

 ments, and carvings were found of the Cave-dwelling Men 

 who flourished from 50,000 to 100,000 years ago. They 

 had for company the lion, bear, mammoth, rhinoceros, and 

 horse, whom they slew for food in vast numbers, with the 

 assistance only of such poor tools as flint knives and bone 

 javelins, at a time when the British Islands were still a 

 solid part of the Continent. 



Gradually the habits of the early horse changed ; 

 speed became of prime importance in the struggle for 

 existence, both to escape from enemies and also to flee 

 from arid districts to places where water could be found ; 

 and as the stature increased so also did the toes become 

 shorter from disuse. In the Middle Tertiary the four 

 toes (Fig. 1) had become only three (Fig. 2), still of 

 equal dimensions, and the size of the animal had 

 increased to that of a fair-sized donkey. 



The form beginning to resemble that of the modern 

 wild Mongolian horse, the Hipparion as it is thence 

 called, continued to develop. Eventually the central 

 digit became unduly elongated, the toe became rounded 

 into hoof-like form (Fig. 3), and the lateral digits 

 resolved themselves into well-developed pettitoes, such 

 as we are familiar with in the domestic pig, and of 



