CHAPTER XIV. 



THE NEOTROPICAL REGION. 



This region, comprehending not only South America but Tropical 

 North America and the Antilles, may be compared as to extent 

 with the Ethiopian region ; but it is distinguished from all the 

 other great zoological divisions of the globe, by the small pro- 

 portion of its surface occupied by deserts, by the large proportion 

 of its lowlands, and by the altogether imequalled extent and 

 luxuriance of its tropical forests. It further possesses a grand 

 mountain range, rivalling the Himalayas in altitude and far 

 surpassing them in extent, and which, being whoUy situated 

 within the region and running through eighty degrees of latitude, 

 offers a variety of conditions and an extent of mountain slopes, 

 of lofty plateaus and of deep valleys, which no other tropical re- 

 gion can approach. It has a further advantage in a southward 

 prolongation far into the temperate zone, equivalent to a still 

 greater extension of its lofty plateaus ; and this has, no doubt, 

 aided the development of the peculiar alpine forms of life which 

 abound in the southern Andes. The climate of this region is 

 exceptionally favourable. Owing to the lofty mountain range 

 situated along its western margin, the moisture-laden trade winds 

 from the Atlantic have free access to the interior. A sufficient 

 proportion of this moisture reaches the higher slopes of the Andes, 

 where its condensation gives rise to innumerable streams, which 

 cut deep ravines and carry down such an amount of sediment, 

 that they have formed the vast plains of the Amazon, of Para- 



