30 Professm- Oiven on the [Feb. 9, 



for retaining a firm grasp of the boughs of trees. In the structure 

 of the carpus, there is a well-marked difference from the human 

 subject, and a retention of the character met with in the lower 

 quadrumana ; the scaphoid bone being divided in the orang-outang. 

 In the chimpanzee the bones of the carpus are eight, as in the 

 human subject, but differ somewhat in form. If the upper ex- 

 tremities are so extraordinary for their disproportionate length, the 

 lower ones are equally remarkable for their disproportionate small- 

 ness in comparison with the trunk, in the orang. The femur is 

 short and straight, and the* neck of the thigh-bone comparatively 

 short. The head of the thigh-bone in this animal, which requires the 

 use of these lower prdiensible organs to grasp the branches of trees, 

 and to move freely in many directions, is free from that ligament 

 which strengthens the hip-joint in man ; the head of the femur in 

 the orang is quite smooth, without any indication of that attach- 

 ment. Here, again, the chimpanzee manifests a nearer approach 

 to man, for the ligamentum teres is present in it, in accordance 

 with the stronger and better development of the whole hind-limb. 

 This approximation, also, is more especially marked in the larger 

 development of the innermost of the five digits of the foot in the 

 chimpanzee, which is associated with a tendency to move more fre- 

 quently upon the ground, to maintain a more erect position than the 

 orang-outang, and to walk further without the assistance of a stick. 

 The foot, in both these species of anthropoid orangs, is characterised 

 by the iDackward position of the ankle-joint, presented by the astra- 

 galus to the tibia, which serves for the transference of the super- 

 incumbent weight upon the foot ; by the comparatively feeble 

 development of the backward projecting process of the calcaneum ; 

 by the obliquity of the articular surface of the astragalus, which 

 tends to incline the foot a little inwards, taking away from the 

 plantigrade character of the creatures and from their capacity to 

 support themselves in an erect position, and giving them an equi- 

 valent power of applying their prehensible feet to the branches of 

 the trees in which they live. 



With reference to the chimpanzee, it was further observed, that, 

 although the number of the true vertebrae is the same as in the 

 orang, yet there is an additional pair of ribs developed ; but, as 

 there are thirteen dorsal vertebrae, we find only four lumbar ones. 

 The modifications pf the pelvis are a close repetition of those of 

 the orang-outang. The chief differences in the skeleton of the 

 chimpanzee are, a shortening and strengthening of the upper extre- 

 mities, an approach towards the characteristic proportions of those 

 parts in man ; the presence of the ligamentum teres of the hip- 

 joint ; and the greater development of the innermost toe in the 

 foot. In both the orang and chimpanzee the skull is articulated by 

 condyles, which are placed far back on its under surface. The 

 cranium is small, characterised by well-developed occipital and sagit- 

 tal ridges ; the occipital ridges in reference to the muscles sustaining 



