26 TYPES OF ANIMAL LIFE 



extended bone. In these apes the bone in question is of 

 enormous size, as it were swollen into a great bony bladder 

 with very thin walls. There can be little doubt but that 

 the resonance of their voice is enormously augmented by 

 this bony drum. In captivity, howling monkeys seem 

 sullen and morose, and, though not petulant, have none of 

 that gentle amiability which is to be found among the 

 next group of American apes, the spider monkeys. 



These latter (Fig. 6) are no less wonderfully adapted for 

 tree life, while they are more active, and seem to represent 

 to a certain extent in the New World, the long-armed apes 

 of the Old, although they are very slow animals compared 

 with the gibbons. Long arms they have indeed, and 

 also legs, whence their name ; but the former do not 

 predominate over the latter at all, as in the gibbons. So 

 powerful is the grip of the spider monkey's prehensile 

 tail, and so dexterously is it used, that not only can 

 the animal's whole body be sustained by means of 

 it, but it even serves as a fifth hand, grasping and 

 bringing to the mouth or paws objects otherwise out of 

 reach. Their prehension in some other respects is sin- 

 gularly defective, as they alone among American monkeys 

 resemble the colobi of Africa, in having no thumbs, or 

 only a minute rudiment of one. They have no cheek 

 pouches, nor has any other New "World ape, and no one 

 of them (as has been already mentioned) has ischiatic 

 callosities. 



Certain monkeys known as woolly monkeys closely 

 resemble those just described, save that they have well- 

 developed thumbs. 



Next comes the group composed of those commonest 

 and most frequently seen of the New World apes, the 

 sapajous, already referred to as being so much in request 

 for tricks and exhibitions. They are considerably 



