in ANIMAL LIFE IN THE TROPICAL FORESTS 307 



liarities. They differ somewhat in dentition and in other 

 structural features from all Old World apes, and a consider- 

 able 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. 



Bats 



Almost the only other order of mammals that is specially 

 and largely developed in the tropical zone is that of the 

 Chiroptera or bats, which becomes suddenly much less plenti- 

 ful when we pass into the temperate regions, and still more 

 rare towards the colder parts of it, although a few species 

 appear to reach the Arctic circle. The characteristics of the 

 tropical bats are their great numbers and variety, their large 

 size, and their peculiar forms or habits. In the East those 

 which most attract the traveller's attention are the great fruit- 

 bats, or fly ing -foxes as they are sometimes called, from the 

 rusty colour of the coarse fur and the fox-like shape of the 

 head. These creatures may sometimes be seen in immense 

 flocks which take hours to pass by, and they often devastate 

 the fruit plantations of the natives. They are often five feet 



