Comparative Osteology of the Orang Ulan and Chimpanzee, 461 



Quadrumanous animal. The outer articulating surface of the astra^ 

 galas is, however, of larger size, and a corresponding disproportion 

 exists between the external and internal malleolus, the latter, from 

 its smaller size, presenting less resistance to the rotation of the tarsus 

 inwards. The os calcis projects further backwards than in the lower 

 Simice, but is more compressed laterally, and of much smaller pro- 

 portional size than in Man. The os naviculare projects further down- 

 wards, and the internal cuneiform bone has a corresponding inclina- 

 tion below the level of the tarsal bones. But whilst the Chimpanzee 

 exhibits the Quadrumanous characters in these particulars, and es- 

 pecially in the curtailed proportion and detached opposable condi- 

 tion of the hallux, it approaches more nearly to Man in the length 

 and strength of that member. The whole foot is much longer than 

 in the human subject; and the entire organization of the inferior 

 members evidently bespeaks a creature destined to reside in forests^ 

 the modifications of the bony structure which add to the facility of 

 climbing and grasping, rendering the entire frame more dependent 

 on the upper extremities for the means of progression and support. 



The size and expansion of the thorax is a marked character in 

 the Chimpanzee : it has thirteen ribs on each side, and the last two 

 pairs are proportionally longer than in Man, the end of the last not 

 being pointed, but widened for the attachment of a cartilage. The 

 sternum is flattened, but not so broad as in the Orang. The har^ 

 monia between its body and the manubrium, and those between the 

 four single pieces of which the body is itself composed, remain visi- 

 ble in the adult skeleton. The clavicle is long and strong, and is 

 not straight, as in the Orang, but sigmoidally curved, though in a 

 less degree than in Man ; while the scapula, on the other hand, re- 

 cedes further from the human type than in the Orang. The hume- 

 rus very closely resembles that of the human subject, but is propor- 

 tionally longer and stronger, and has its twist more strongly marked 

 and lower down on the bone. As the segments of the limbs recede 

 further from the trunk they become subject to greater and more 

 varied modifications. Thus the disproportionate length of the hu- 

 merus is succeded by a still greater elongation of the fore-arm, the 

 bones of which are also more curved from each other than in Man, 

 and the inter-osseous space consequently enlarged. The bones of 

 the carpus are the same in number as in the human subject ; but the 

 trapezium and trapezoides are proportionally smaller, while the os 

 pisiforme nearly equals the os magnum. The thumb does not quite 

 equal in length the metacarpal bone of the first finger, and is as 

 slender and weak as it is short. Some little disproportion also exists 

 between the relative lengths of the fingers; but taken together they 

 are relatively stronger and more elongated than in Man. 



After completing his detailed examination of the skeleton, Mr. 

 Owen reverts to the changes which it undergoes in its progress to 

 maturity, especially as regards the proportions of the head and face ; 

 and states that he has derived full confirmation of the identity of 

 species in the young and adult crania, from a comparison of the 

 crowns of the permanent teeth lodged within the jaws of the young 



