346 QUADRUMANA. 



are more equal : being semi-terrestrial in their habits, and inhabiting, 

 as many do (the Chacma and Magot, for example), the recesses and 

 summits of rocks, the extent of reach possessed by the truly arboreal 

 species is not needed ; and, besides, arms disproportionately long would 

 render their movements on the ground slow and embarrassed : as it is, 

 their shuffling canter enables them to escape, except from enemies of 

 tolerable fleetness. The shape of the pelvis has been previously de- 

 scribed : it may here be added, that the thigh-bone (or femur) is straight, 

 and the interspace between the tibia and fibula, greater than in Man. The 

 os calcis projects ; the foot is narrow, and the fingers are slender ; but 

 the thumb is well developed, and its metatarsal bone, though shorter 

 than that of the first hind finger, far exceeds it in stoutness. 



The sole of the foot is obliquely inward, owing to the mechanism of 

 the ankle-joint, of which the motion is very free. As may be easily con- 

 ceived, this position of the foot, or posterior grasper, is of the greatest 

 advantage to a quadrumanous climbing animal, inasmuch as it renders 



Skeleton of Mandrill. 



the application of the sole to the trunk of a tree, or to a branch rising 

 perpendicularly, unforced and natural. Hence is it that the Monkey 

 grasps a pole so readily with his hind feet, while climbing up, or while 

 descending. 



The position of the skull, with respect to the spine, preponderating, as 

 it does, anteriorly, requires a far greater development of the trapezii, serrati, 

 rhomboidei, and the other muscles inserted into the occipital bone, as well 

 as a larger attachment of them : hence the' T neck appears short and 

 thick, especially in some species (the Mandrill, for example), which have 

 a large head, an elongated snout-like muzzle, and which habitually move 

 on all-fours, carrying the body horizontally. In the Mandrill, and other 



