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 
