312 ANIMALS OF EGA. Chap. V. 



scarlet-face was missing, having made his escape into 

 the forest. Two men were sent in search of him, but 

 returned after several hours' absence without having 

 caught sight of the runaway. We gave up the monkey 

 for lost, until the following day, when he re-appeared on 

 the skirts of the forest, and marched quietly down the 

 bowsprit to his usual place on deck. He had evidently 

 found the forests of the Rio Negro very different from 

 those of the delta lands of the Japura, and preferred 

 captivity to freedom in a place that was so uncongenial 

 to him. 



A most curious fact connected with this monkey is 

 the existence of an allied form, or brother species, in a 

 tract of country lying to the west of its district. This 

 differs in being clothed with reel instead of white hair, 

 and has been described by Isidore GeofTroy St. Hilaire 

 (from specimens brought to Paris in 1847 by the Comte 

 de Castlenau) as a distinct species, under the name of 

 Brachyurus rubicundus. It wholly replaces the white 

 form in the western parts of the Japura delta : that is 

 to say, in a uniform district of country, 150 miles in 

 length, and sixty to eighty in breadth, the eastern half 

 is tenanted exclusively by white Uakaris, and the 

 western half by red ones. The district, it may be men- 

 tioned, is crossed by several channels, which at the 

 present time doubtless serve as barriers to the dispersal 

 of monkeys, but cannot have done so for many centuries, 

 as the position of low alluvial lands, and the direc- 

 tion of channels in the Amazons Valley, change con- 

 siderably in the course of a few years. The red-haired 

 Uakari appears to be most frequently found in the 



