THE MAN-LIKE APES. 41 



the body requiring to be kept up, either by touching the 

 ground with the knuckles, first on one side then on the 

 other, or by uplifting the arms so as to poise it. As with 

 the Chimpanzee, the whole of the narrow, long sole of the 

 foot is placed upon the ground at once and raised at once, 

 without any elasticity of step." 



After this mass of concurrent and independent testi- 

 mony, it cannot reasonably be doubted that the Gibbons 

 commonly and habitually assume the erect attitude. 



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 ordi- 

 nary 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 ex- 

 hibits 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 at- 

 tained by the right hand again, and quitted instantane- 

 ously, 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 mani- 



