3J4 THE HIND FOOT OR PES. [CHAP. 



the same in number and relative position, but the articular 

 surface of the internal cuneiform for the hallux is saddle- 

 shaped, and is directed obliquely towards the inner or 

 tibial side of the foot. The consequence is that the hallux 

 is not only somewhat separated from the other digits, but 

 is also set in a different plane, so that when it is flexed it 

 turns towards the sole of the foot, and becomes opposed to 

 the others, much as the thumb does in the human hand. 

 It is this peculiarity of 'the pes which has given rise to the 

 term quadrumanous t Qi "four-handed," occasionally applied 

 to this group of animals. 



The hallux is usually relatively shorter than it is in Man. 

 In the Orang (Simia satynis] it is particularly short, and 

 often wants the terminal phalanx, while the metatarsals and 

 the phalanges of the other digits are long and curved, the 

 proportions of the three segments of the foot being exactly 

 the reverse of those of Man, as the tarsal segment is 

 shortest, and the phalangeal the longest. 



The form of the articular surface of the astragalus, and 

 especially the free mobility of the navicular and cuboid 

 bones on the astragalus and calcaneum, cause the foot of 

 the Orang to be set very obliquely on the leg, so that when 

 placed on a level surface the fibular border only rests on the 

 ground, and the sole is directed inwards. This position suits 

 well for grasping vertically-placed boughs of trees, but is ill 

 adapted for standing or walking on the ground. A similar 

 disposition is seen in a varying degree in most of the 

 Monkeys, but in none so markedly as the Orang, in which 

 animal all the peculiarities by which the simian is distin- 

 guished from the human foot are most strikingly displayed. 



There are usually two sesamoid bones below each 

 metatarso-phalangeal joint, and a single one below the 

 cuboid in the tendon of the peroneus longus muscle. 



