SOME EXTINCT ARGENTINE MAMMALS 87 



the living tapirs, but it is more nearly paralleled by the 

 elephants, and still more closely by the aquatic dugong, while 

 among whales the backwardation (if I may coin a word) 

 of the nostrils is carried to a still greater degree. That 

 a land mammal with its nostrils situated in this unusual 

 position could not have managed to exist without a trunk 

 seems evident, and we may therefore conclude that the 

 macrauchenia was so furnished ; while, from its long 

 slender neck and limbs, it may further be inferred that 

 it was an inhabitant of open plains or thin forest, and 

 was not a frequenter of marshes and swamps. It may be 

 added that in its uninterrupted and even series of teeth 

 the macrauchenia differs from all existing mammals save 

 man, and agrees with its distant cousin, the homalodonto- 

 there. 



From its large size, the peculiar position of its nostrils, 

 and the characters of its cheek-teeth, the naturalist is led 

 to infer that the macrauchenia was a highly specialised 

 creature ; and it is interesting to find that this inference 

 is converted into a certainty by the existence of certain 

 kindred forms in the older formations of the Parana and 

 Patagonia, which are evidently the ancestral types from 

 which the Pampean genus has originated. All these crea- 

 tures were of relatively small size, with cheek-teeth more 

 closely resembling those of the odd-toed ungulates, and 

 they show a gradual transition in regard to the position 

 of the nostrils from the type of the macrauchenia to the 

 ordinary form. The evolution of such an extraordinary 

 creature as the one under consideration is therefore fully 

 explained, although we have yet to learn the special reason 

 for the peculiar position of its nostrils and the development 

 of a trunk. 



More or less intimately allied to the ancestors of the 



