THE SPIDER-MONKEYS. 247 
gion, and, to condense Mr. Wallace’s account of it, it is of com- 
paratively small extent ; but the whole of its area is mountainous, 
being, in faet, a continuation of the great range of the Rocky 
Mountains. It varies in elevation above the sea from 6,000 to 
18,000 feet. ‘‘ With the exception of the elevated plateaus of 
Mexico and Guatemala, and the extremity of the peninsula of 
Yucatan, the whole of Central America is clothed with forests ; 
and as its surface is much broken up into hill and valley, and 
the volcanic soil of a large portion of it is very fertile, it is 
altogether well adapted to support a varied fauna, as it does a 
most luxuriant vegetation.” In this region only species of 
Spider-Monkeys (Aze/es), of Howlers (Alouatta), of Capuchins 
(Cebus), of Night-Monkeys (Vyctipithecus), and of Squirrel- 
Monkeys (Crysothrix) are found. The Spider-Monkeys and 
the Howlers alone extend so far North as Mexico, and the 
Night-Monkeys reach to Nicaragua, while the Squirrel-Mon- 
keys and Capuchins have penetrated no further than to Costa 
Rica. | 
The Brazilian Sub-region includes all the open plains and 
pasture lands, surrounded by, or intimately associated with, the 
forests. Its central mass consists of the great forest plain of 
the Amazons, from the north-east coast of Brazil to high up in 
the Andes on the west, a stretch of more than 2,000 miles ; 
and from the mouth of the Orinoko to near La Paz in the 
Bolivian Andes, a distance of 1,900 miles, of continuous forest 
“ campos ” 
in both directions. Within this area are some open 
or patches of pasture lands, along several of the tributaries of 
the Amazon, and Llanos—open flat plains generally flooded in 
the wet season—on the northern bank of the Orinoko. Un- 
broken forest also covers the country from Panama _ south- 
wards by the Magdalena Valley along the western aspect of the 
