118 TROPICAL NATURE, AND OTHER ESSAYS. 



tlie proboscis monkey of Borneo, whose long fleshy nose 

 gives it an aspect very different from that of most of its 

 allies. 



In tropical America monkeys are even more abundant 

 than in the East, and they present many interesting 

 peculiarities. They differ somewhat in dentition and 

 in other structural features from all Old World apes, 

 and a considerable number of them have prehensile 

 tails, a peculiarity never found elsewhere. In the 

 howlers and the spider monkeys the tail is very long 

 and powerful, and by twisting the extremity round a 

 branch the animal can hang suspended as easily as other 

 monkeys can by their hands. It is, in fact, a fifth hand, 

 and is constantly used to pick up small objects from the 

 ground. The most remarkable of the American monkeys 

 are the howlers, whose tremendous roaring exceeds that 

 of the lion or the bull, and is to be heard frequently at 

 morning and evening in the primeval forests. The 

 sound is produced by means of a large, thin, bony 

 vessel in the throat, into which air is forced ; and it is 

 very remarkable that this one group of monkeys should 

 possess an organ not found in any other monkey or even 

 in any other mammal, apparently for no other purpose 

 than to be able to make a louder noise than the rest. 

 The only other monkeys worthy of special attention are 

 the marmosets, beautiful little creatures with crests, 

 whiskers, or manes ; in outward form resembling squirrels, 

 but with a very small monkey-like face. They are either 

 black, brown, reddish, or nearly white in colour, and are 

 the smallest of the monkey tribe, some of them being 

 only about six inches long exclusive of the tail. 



1)0 fs. — Almost the only other order of mammals that 



