354 ORIGIN OF LIFE IN AMERICA 



obviously of the same family from the Patagonian and 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 



* ScUosser, M,, "TuUberg's System der Nagethiere," pp. 741 — 

 742. 



