222 ON THE NATURAL HISTORY 



But level ground is not the place where these animals 

 can display their very remarkable and peculiar locomotive 

 powers, and that prodigious activity which almost tempts 

 one to rank them among flying rather than among ordinary 

 climbing mammals. 



Mr. Martin (1. c. p. 430) has given so excellent and graphic 

 an account of the movements of a Hylobates agilis, living in 

 the Zoological Gardens, in 1840, that I will quote it in full : 



" It is almost impossible to convey in words an idea of 

 the quickness and graceful address of her movements : they 

 may indeed be termed aerial, as she seems merely to touch 

 in her progress the branches among which she exhibits her 

 evolutions. In these feats her hands and arms are the sole 

 organs of locomotion ; her body hanging as if suspended 

 by a rope, sustained by one hand (the right, for example), 

 she launches herself, by an energetic movement, to a distant 

 branch, which she catches with the left hand ; but her hold 

 is less than momentary : the impulse for the next launch 

 is acquired : the branch then aimed at is attained by the 

 right hand again, and quitted instantaneously, and so on, 

 in alternate succession. In this manner spaces of twelve 

 and eighteen feet are cleared, with the greatest ease and 

 uninterruptedly, for hours together, without the slightest 

 appearance of fatigue being manifested ; and it is evident 

 that, if more space could be allowed, distances very greatly 

 exceeding eighteen feet would be as easily cleared ; so that 

 Duvaucel's assertion that he has seen these animals launch 

 themselves from one branch to another, forty feet asunder, 

 startling as it is, may be well credited. Sometimes, on 

 seizing a branch in her progress, she will throw herself, by 

 the power of one arm only, completely round it, making a 

 revolution with such rapidity as almost to deceive the eye, 

 and continue her progress with undiminished velocity. It 

 is singular to observe how suddenly this Gibbon can stop, 

 when the impetus given by the rapidity and distance of 

 her swinging leaps would seem to require a gradual abate- 

 ment of her movements. In the very midst of her flight 

 a branch is seized, the body raised, and she is seen, as if by 

 magic, quietly seated on it, grasping it with her feet. As 

 suddenly she again throws herself into action. 



" The following facts will convey some notion of her 

 dexterity and quickness. A live bird was let loose in her 

 apartment ; she marked its flight, made a long swing to 

 a distant branch, caught the bird with one hand in her 



