1859.] on the Gorilla, 19 



that of man. It is relatively largest in the gorilla. In this ape the 

 thumb reaches to a little beyond the base of the first phalanx of the 

 fore-finger ; it does not reach to the end of the metacarpal bone of the 

 fore-finger in the chimpanzee, orang, or gibbon ; it is relatively smallest 

 in the last tailless ape. In man the thumb extends to or beyond the 

 middle of the first phalanx of the fore-finger. The philosophical zoolo- 

 gist will see great significance in the results of this comparison. Only 

 in the gorilla and chimpanzee are the carpal bones eight in number, as 

 in man ; in the orangs and gibbons they are nine in number, as in the 

 tailed monkeys. 



The scapulse are broader in the gorilla than in the chimpanzee, 

 orang, or long-armed apes ; they come nearer to the proportions of that 

 bone in man. But a more decisive resemblance to the human structure 

 is presented by the iliac bones. In no other than the gorilla do they 

 bend forward, so as to produce a pelvic concavity ; nor are they so 

 broad in proportion to their length in any ape as in the gorilla. In 

 both the chimpanzee and orang the iliac bones are flat, or present a 

 concavity rather at the back than at the forepart. In the siamang they 

 are not only flat, but are narrower and longer, resembling the iliac 

 bones of tailed monkeys and ordinary quadrupeds. 



The lower limbs, though characteristically short in the gorilla, are 

 longer in proportion to the upper limbs, and also to the entire trunk, 

 than in the chimpanzee ; they are much longer in both proportions and 

 more robust than in the orangs or gibbons. But the guiding points of 

 comparisons here are thejieel and the hallux (great toe or thumb 

 of the foot). 



The heel in the gorilla makes a more decided backward projection 

 than in the chimpanzee ; the heelbone is relatively thicker, deeper, 

 more expanded vertically at its hind end, beside being fully as long as 

 in the chimpanzee : it is in the gorilla shaped and proportioned more like 

 the human calcaneum than in any other ape. Among all the tailless 

 apes the calcaneum in the siamang and other gibbons least resembles 

 in its shape or proportional size that of man. 



Although the foot be articulated to the leg with a slight inversion 

 of the sole it is more nearly plantigrade in the gorilla than in the chim- 

 panzee. The 6rang departs far, and the gibbons farther, from the human 

 type in the inverted position of the foot. 



The great toe which forms the fulcrum in standing or walking is 

 perhaps the most characteristic peculiarity in the human structure ; it 

 is that modification which diff'erentiates the foot from the hand, and 

 gives the character to his order (Bima?ia). In the degree of its 

 approach to this development of the hallux the quadrumanous animal 

 makes a true step in affinity to man. 



The orang-utan and the siamang, tried by this test, descend far and 

 abruptly below the chimpanzee and gorilla in the scale. In the orang 

 the hallux does not reach to the end of the metacarpal of the second 

 toe ; in the chimpanzee and gorilla it reaches to the end of the first 

 phalanx of the second toe ; but in the gorilla the hallux is thicker and 

 stronger than in the chimpanzee. In both, however, it is a true thumb, 



c2 



