THE UKARI MONKEYS. i8t 



frisky little fellow had been reared in the house among the 

 children, and allowed to run about freely. . . ." This 

 species is rare, even in the limited district which it inhabits. 

 A Government official sent six of his most skilful Indians, 

 who were absent hunting for three weeks before they obtained 

 twelve specimens. 



In reference to the singularly restricted range of these 

 Uakari's, Mr. Wallace's observations in his paper "On the 

 Monkeys of the Amazon," before the Zoological Society of 

 London, are of great interest. 



" During my residence," he says, " in the Amazon district, I 

 took every opportunity of determining the limits of species, 

 and I soon found that the Amazon, the Rio Negro, and the 

 Madeira formed the limits beyond which certain species never 

 passed. The native hunters are perfectly acquainted with this 

 fact, and always cross over the river when they want to pro- 

 cure particular animals, which are found even on the river's 

 bank on one side, but never by any chance on the other. On 

 approachmg the sources of the rivers, they cease to be a bound- 

 ary, and most of the species are found on both sides of them. 

 Thus several Guiana species come up to the Rio Negro and 

 Amazon, but do not pass them ; Brazilian species, on the con- 

 trary, reach but do not pass the Amazon to the north. Several 

 Ecuador species from the east of the Andes reach down into 

 the tongue of land between the Rio Negro and Upper Ama- 

 zon, but pass neither of those rivers, and others from Peru are 

 bounded on the north by the Upper Amazon, and on the east 

 by the Madeira. Thus there are four districts whose bound- 

 aries on one side are determined by the rivers I have men- 

 tioned. In going up the Rio Negro, the difference on the two 

 sides of the river is very remarkable, 



