490 Zoological Society. 



gation of the short arm of the lever (which every bone represents) 

 in proportion to the long arm of the same ; or (otherwise expressed) 

 on the extent of the distance between the fulcrum and weight in 

 proportion to the distance between the fulcrum and the power. 



As respects the proportions of the fore-limbs, the Orang Utan 

 approaches the Gibbons, and retrogresses from Man more, than the 

 Chimpanzee, since in the former the arms reach to the heel, in the 

 latter to about the knee-joint. 



Section IV. — Of the Hind Extremities. 



The pelvis presents us with a type far degraded from the Bimanous. 

 The hips are narrow ; the iliac bones long and flat, and their superior 

 margins do not present an arc of a circle, as in Man, and indeed to 

 a certain extent in the Chimpanzee. The ischiatic bones, instead of 

 retreating far backward from the symphysis of the pubes, are nearly 

 on a plane with the iliac wings ; their inferior margins are not cir- 

 cular, as in Man, but present three sides of a lengthened parallelo- 

 gram. The symphysis of the pubic bones resembles that of Man 

 more than does that of the young Chimpanzee. 



The bones of the lower extremities are characterized, as those of 

 the pectoral limbs, by the slenderness of their form and the slightness 

 of their elevations. 



The trochanters of the femur are small ; the tinea aspera absent. 

 The ligamentum teres appears to have been present, thus agreeing 

 with Man and all the Simiadce, excepting the Orang Utan. 



The tibia and fibula have rather a larger interosseous space than 

 in Man, consequent on the bowing of the fibula. This space is large 

 in the Orang Utan (Owen, ut)i supra). 



The relative proportions of the leg and fore-leg are similar to the 

 human. 



Let me here introduce a remark made on this animal by Yarrell, 

 viz. that both the upper and lower extremities are incapable of the 

 same extension as in Man, owing to the strong facial expansion of 

 the flexor tendons passing before the elbows and behind the knee- 

 joints to be attached to the upper halves of their respective bones 

 below these parts (Notes on Dissection of Active Gibbon, Zoological 

 Journal, vol. v. p. 14). 



The foot is remarkable for the smallness of the os calcis, a character 

 common to the Orangs and the lower Monkeys, and which, giving 

 less basal surface to the foot, indicates less power of supporting the 

 frame in the erect posture. The hind-foot is formed for grasping 

 the branches of trees and not for walking on the ground. The meta- 

 tarsal bones decrease in strength (as in the hand) from the first 

 towards the little finger. The thumb is strongly formed, especially 

 its metatarsal bone. The ungueal phalanges are wanting in the 

 second and third finger, and the ungueal and penultimate in the little 

 finger of the only hind extremity mounted on the skeleton. These 

 defects in the hind- foot arise from the animal having been aff'ected 

 some time previous to her death with a morbid state of constitution 

 (supposed to arise from confinement), which caused her to gnaw off 



