MAMMALIA. 657 



the wings during flight ; and, in order to give those muscles a 

 sufficient extent of origin, the sternum, although exhibiting the 

 general characters of that of a quadruped, is deeply carinated 

 along the mesial line. The hurnerus is of moderate length, but 

 the fore-arm prolonged and slender; it consists, in fact, of but 

 one bone, so that all movements of pronation and supination 

 are necessarily impracticable. The carpal bones present their 

 usual structure and arrangement at the base of the hand ; but 

 those of the metacarpus, excepting that of the thumb, are so 

 extraordinarily lengthened, that they themselves form a consider- 

 able portion of the framework of the wing, which is completed 

 by the phalanges of the fingers appended to their extremities. 

 All these wire-like fingers are connected together by a broad 

 duplicature of skin, derived from the sides of the body, which is 

 continued along the whole length of the hind legs, and even fills 

 up the interspace between these last and the tail ; this membrane 

 forms an expansion sufficiently extensive to become converted into 

 an organ of flight. The fingers composing this strange hand 

 are obviously incapable of closing towards the palm, as ours do 

 when grasping an object : their only movements are such as fold 

 up the wing against the side of the body, by laying the fingers 

 close along the side of the fore-arm, as in closing a fan. The 

 thumb alone is left free; and this being short, and armed with a 

 strong nail, is employed in enabling the creature to cling to some 

 elevated object in those gloomy lurking-places wherein it hides 

 during the day. 



(738.) The QUADRUMANA, next to mankind the most ele- 

 vated members of the animal creation, are, as is evident from every 

 point of their organization, the destined inhabitants of the trees ; 

 neither will it appear astonishing, when we consider the extensive 

 provision that has been made for the support of animal life amid 

 the dense and pathless forests of tropical climates, that animals so 

 intelligent, and capable of enjoyment, should have been widely 

 disseminated through extensive regions of our globe. 



The great distinction characteristic of the Quadrumana is found 

 in the organization of their feet, all of which are converted into 

 prehensile instruments, whereby they can seize the boughs of the 

 trees wherein they reside, and thus securely swing themselves from 

 branch to branch, or even leap from one tree to another, with won- 

 derful activity and precision. Their hands are constructed upon 

 the same principle as those of Man ; their thumbs, although less 



