SKELETON OF QUADRUMANA. 545 



radius and ulna are remarkable for their length, and the extent 

 of the interosseous space. The wrist, fig. 361, consists of nine 

 bones, as in the inferior Apes, — resulting, as in them, from the 

 presence of the intermedium, h : the scaphoid, a, and lunare, b, 

 articulate with the radius ; the cuneiform, c, is attached by liga- 

 ment to the styloid process of the ulna ; the ' sesamoid,' i, is 

 imbedded in the tendon of the abductor longus pollicis. The 

 metacarpals have only half the breadth of the proximal phalanges 

 at their middle part. The phalanges are long, bent towards the 

 palm, and expanded at their middle. The bones of the thigh and 

 leg are disproportionately short : the articulation of the latter with 

 the tarsus is adjusted to turn the sole obliquely inward. The 

 hallux is disproportionately short, and, in some Orangs, has but 

 one phalanx. The bones of the other toes have great length, 

 especially the metatarsals and proximal phalanges, which are bent 

 toward the sole, indicating the habitual application of the foot in 

 the act of grasping and climbing. The joint of the hind-limb is 

 made as free as that of the fore-limb, by the absence of the inter- 

 articular ' ligamentum teres.' The calcaneum projects but little 

 beyond the astragalus, the tibial surface of which is inclined 

 obliquely inward, so that the foot presents its outer edge to the 

 ground, — a mode of articulation favouring its prehensile power. 



In the Chimpanzee, fig. 345, the clavicle, 58, is relatively 

 shorter than in the Orang ; the sigmoid curvature is more marked, 

 the sternal end is thicker, and the acromial end broader : the 

 scapula is longer in proportion to its breadth, and the acromion is 

 broader than in the Orang. The bones of the anterior extremity, 

 especially those of the fore-arm, are shorter than in the Orang. 

 The humerus, 53, is imperforate at its distal end ; it is shorter 

 and stronger than the Orang ; both tuberosities are more deve- 

 loped, especially the inner one, and the bicipital groove is deeper : 

 the antero-internal surface, bounded outwardly by the deltoidal 

 ridge, is flatter than in the Orang : the supinator ridge commences 

 above the middle of the shaft. The trochlear prominence of the 

 distal articulation is more developed, and the canal which sepa- 

 rates it from the ball for the radius is both deeper and wider. 

 The radius, 54, is shorter in proportion to its breadth, and pre- 

 sents a more marked sigmoid curvature ; the borders of the 

 circular proximal end are more produced ; the trihedral character 

 of the distal half is better marked. The distal end is more sud- 

 denly expanded, and the grooves for the extensor tendons are 

 deeper and better defined. The ulna, 55, diifers from that in the 

 Orang in the proportion of its length and thickness. The outer 



VOL. II. N N 



