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 in both directions. Within this area are some open "campos" 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. Unbroken forest also covers the country from Panama southwards by the Magdalena Valley along the western aspect of the {248}Andes to Guayaquil. There is a very arid tract on the northeast coast of Brazil; but south of Cape San Roque the coast forests extend to 30° south latitude, "clothing all the valleys and hill-sides as far inland as the higher mountain ranges, and even penetrating up the great valleys far into the interior. To the south-west the forest country reappears in Paraguay, and extends in patches and partly wooded country till it almost reaches the southern extension of the Amazonian forests. The interior of Brazil is thus in the position of a great island plateau, rising out of, and surrounded by, a lowland region of ever-verdant forests." Of its Anthropoid life the Woolly Monkeys (_Lagothrix_), the Sakis (_Pithecia_), and the Uakaris (_Brachyurus_) are confined to its Amazonian forests. The Woolly Spider-Monkeys (_Brachyteles_) keep to the wooded coast-regions of South-east Brazil, while the Titis (_Callithrix_) do not range out of the tropics of South America. The Howlers (_Alouatta_), the Spider-Monkeys (_Ateles_), and the Capuchins (_Cebus_) roam nearly over the whole region--the first and last ranging from Costa Rica to Paraguay as well. The Spider-Monkeys indeed extend over to the west side of the Equatorial Andes, and in Guatemala across to the Pacific coast. No species of Monkey, however, is known to inhabit the western side of the Andes, to the south of the Gulf of Guayaquil. THE BABOONS, GUEREZAS AND LANGURS. FAMILY CERCOPITHECIDÆ.