406 OBIGIN OF LIFE IN AMERICA 



with western North America, with southern Africa and with 

 New Zealand and Australia. 



As we ascend the Andes from northern Argentina, we meet 

 with a familiar animal which we generally associate with Peru 

 and its inhabitants, namely, the llama. The llama is only a 

 domestic animal. But its wild ancestor the huanaco (Lama 

 huanachus) still exists plentifully in the Andes of Peru and 

 Chile, as well as in the plains of Patagonia. Its western dis- 

 tribution, like that of the bear, some of the deer and many 

 vertebrates and invertebrates, is thus very marked and de- 

 mands an explanation. For the benefit of those who may 

 be unacquainted with the pedigree of this creature I may men- 

 tion that the huanaco and its domesticated relations the llama 

 and alpaca, are essentially camels in structure. There are 

 certain differences in the teeth, the huanaco being with- 

 out a hump and smaller than the camel, while the head is 

 more like that of a sheep. But the shape and structure of the 

 skull and bones and the general anatomy are very similar 

 in the huanaco and camel, implying that they have descended 

 from the same ancestor. The occurrence of the camels in Asia 

 and of the llamas in South America is a case of widely dis- 

 continuous distribution of two related genera and thus points 

 to an ancient origin. The geological history of the family is 

 of the greatest interest. The first member of the camel tribe 

 makes its appearance in Argentina in a deposit known as the 

 Lower Pampean, which Dr. Ameghino considers of Pliocene 

 age, though some authorities think it is more recent. Here 

 occurs Palaeolama, an extinct ancestor of the huanaco. In 

 the upper portions of the same deposit the remains of quite 

 a number of llama-like creatures have been discovered such 

 as Protauchenia, Hemiauchenia, Stilauchenia and Mesolama, 

 as well as the huanaco itself. That is about all we know of the 

 past history of these camel -like animals of South America. 

 The fact that no members of the family are known from earlier 

 deposits than Pliocene, and that the extinct genera are nearly 

 related to the living one, suggests that the ancestors of the 

 huanaco were not originally native to South America but in- 

 vaded the continent from elsewhere. Africa and Europe no 

 longer were connected with South America. North America 

 is thus the only possible source whence the ancestral huanacos 



