54 THE GEOGRAPHY OF MAMMALS 



at any period of their history, been joined to the mainland, 

 and that, owing to the fact that they are situated in the 

 region of equatorial cairns, immigration from the mainland 

 is very occasional. In this way has been gradually evolved 

 the peculiar fauna, which, although highly specialised, 

 shows abundant evidence of its having been derived from 

 the nearest mainland. 



Section II. — General View of the Mammal-fauna 

 of the Neotropical Region 



The Neotropical Region is essentially one of luxuriant 

 tropical vegetation, the great mass of the land from Central 

 America to Uruguay being occupied by vast forests. South 

 of the tropic of Capricorn the woods soon disappear, and 

 the country, over a large part of its surface, becomes a flat 

 treeless expanse covered with more or less abundant pasture 

 known as the Pampas, while all along the western coast 

 extends the giant range of the Andes, the eastern flanks of 

 which are, as a rule, well watered and wooded, while the 

 western slopes from the Gulf of Guyaquil to the island of 

 Chiloe facing the Pacific are utterly dry and arid. There 

 are, however, also in the higher parts of Venezuela, the 

 Guianas, and Brazil, open grassy plains called " campos," 

 which rise as islands from a surrounding sea of evergreen 

 tropical forest. 



The mammalian fauna of the Neotropical Region is 

 naturally a rich one, but in the number of genera and 

 species falls considerably short of that of the Ethiopian 

 Region. This may perhaps be accounted for by the 

 physical features of the country, which are certainly not 



