406 
ORIGIN 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 
