Zoological Society. 489 



The scapulae are of a more lengthened shape than in the human 

 subject, from which they also differ in having the aspect of the gle- 

 noid cavity far less laterally and more upwardly directed, in the 

 upper edge of the bone rather descending than ascending from this 

 cavity, in the convexity instead of concavity of the humeral edge, 

 and the far greater acuteness of the inferior angle. 



The peculiarities to be remarked in the humerus are its extraordi- 

 nary length, reaching to just above the head of the femur, its slight- 

 ness of form, and the general weakness of its elevations. The tuber- 

 cles at the superior head are very small. Its twist occurs about 

 one-third from the upper extremity of the bone, as in Man, The 

 external apophysis can scarcely be said to exist ; the internal is 

 present. 



The fore-arm is remarkable for its length (which is yet more ex- 

 traordinary than that of the arm), for the slenderness of its form, 

 and for the extent of the interosseous space formed by the great 

 outward curvature of the radius : by this last character the Gibbon 

 is distanced from Man, but approximated to the Orangs. The greatest 

 distance of the radius from the ulna occurs about one-third of the 

 length of the fore- arm from the superior articulation ; not near the 

 inferior head, as in the human skeleton. The olecranon of the ulna 

 appears neither so broad nor so strong as in Man. 



In this specimen the fore-arm is two inches longer than the arm. 

 In the adult Hoolock the difference is about 1 1 inch ; in the Hylo- 

 bates concolor about 2^ inches. These proportions correspond with 

 those of the Orangs, but are at variance with the human, where the 

 arm is about two inches longer than the fore-arm. Now it is re- 

 markable that in the immature Gibbons the proportion of these 

 parts has been found to resemble the human (see Dr. Harlan, uhi 

 supra). Not only then are the skulls of these monkeys more anthro- 

 poid in youth than maturity, but likewise the proportions of the an- 

 terior extremities. Retrogression with advancing age from a superior 

 to an inferior type of organization is not so common in nature as the 

 converse. 



The carpus of the Agile Gibbon appears to contain the same eight 

 bones as in Man ; not eleven, as Daubenton states that the Hylobates 

 lar possesses (Martin, uhi supra). The whole hand is remarkable 

 for its slenderness and length, by which it is beautifully adapted for 

 grasping the boughs of trees or any such objects : the fingers main- 

 tain similar proportions, one to another, to those of Man. The 

 thumb, longer than in the Chimpanzee, where it does not quite equal 

 in length the metacarpal bone of the first finger, is slender in form. 



So extraordinary is the length of the fore extremity, that the hu- 

 merus reaches to nearly the same part of the trunk as the wrist in 

 Man, and that the fingers really rest on the ground when the animal 

 assumes the erect posture. The length of the fore-arm of this ske- 

 leton, whose total height is only about two feet, positively exceeds 

 in length that of the adult human subject, being eleven inches long. 



Never have I seen a skeleton which better illustrates the law of 

 animal mechanics, that rapidity of movement depends on the elon- 



Ann. ^ Mag. N. Hist. Vol. xvii. Suppl. 2 L 



