354 
ORIGIN OF LIFE IN AMERICA 
obviously of the same family from the Patagonian ancl Argen¬ 
tine Eocene, Oligocene, Miocene and Pliocene beds, so that 
it would seem, as he indeed suggests, as if South America 
had been the original home of the family. Professor Schlosser 
quite agrees that these are the undoubted ancestors of the still 
existing South American genera, but he thinks that Dr. 
Ameghino is mistaken about the age of the South American 
deposits in which these rodents occur. He believes them to 
be not earlier than Miocene, while more primitive ancestors 
of these rodents are to be found in European Oligocene beds. 
The Theridomyidae of Europe which, according to Professor 
Schlosser, have given rise to Chinchilla and its relatives, are 
more primitive in structure than the latter and nearly allied 
to them. The same writer acknowledges that other groups of 
mammals also entered South America from Europe, although 
he does not give us the least clue as to the means they em¬ 
ployed in doing so. Whether Chinchilla and its relations are 
descended from European ancestors, or whether the European 
Theridomyidae have been derived from South America, is 
really comparatively immaterial to our present enquiries. The 
important point at issue is the recognition, by such an autho¬ 
rity as Professor Schlosser,* that the two continents have had 
a faunistic interchange about Oligocene times in which North 
America took no part. 
Ecuador possesses such a number of quaint archaic forms 
of animal life that I have scarcely been able to give a general 
sketch even of the main features of the fauna, but before 
dealing with the causes that produced them I must mention 
one more instance. It is the most noteworthy perhaps of the 
whole deer-tribe, namely, the little pudu (Pudua mephisto- 
pheles). No larger than a hare, this tiny creature, with its 
simple unbranched spike-antlers, reminds us of some of the 
early progenitors of the deer-tribe. The genus Pudua has two 
species, both entirely confined to western South America, like 
the bear and Chinchilla. One of these lives in the mountains 
of Ecuador, the other in Chile and on the island of Chiloe. 
I need not repeat the remarks made in an earlier chapter 
* Schlosser, M., “ Tullberg’s System der Nagethiere,” pp. 741— 
742. 
