THE DONKEY'S ANCESTORS. 191 



of the earth towards the very close of the 

 tertiary period. 



Of course everybody knows the wonderful 

 pedigree of the horse and donkey family, 

 which has been discovered imprinted upon 

 the later formations of America by Professor 

 Marsh, and reconstructed for us in full by 

 Professor Huxley. The horses are an ex- 

 tremely aberrant form of the ungulate tribe, 

 and their very earliest recognisable ancestor 

 must have had some points of resemblance 

 with the tapirs, some with the pigs, some 

 with the deer nay, some even with the pro- 

 totype of the lemurs and of man himself. In 

 the lowest eocene beds of New Mexico, 

 Professor Marsh has found the first shadowy 

 forerunner of my donkey an equine quad- 

 ruped which he has appropriately called 

 eohippus, with five toes to each hind foot, 

 and probably to each forefoot as well. 

 Already, however, this very vague progenitor 

 of the horse family had begun to develop 



