1859.] on the Gorilla. 13 



progression, is manifested by these callosities. The back of the hand 

 is hairy as far as the divisions of the fingers ; the palm is naked and 

 callous. The thumb, besides its shortness, according to the standard 

 of the human hand, is scarcely half so thick as the fore-finger. The 

 nail of the thumb did not extend to the end of that digit ; in the 

 fingers the nail projected a little beyond the end, but with a slightly 

 convex worn margin, resembling the human nails in shape, but rela- 

 tively less. 



In the hind limbs, chiefly noticeable was that first appearance in the 

 quadrumanous series of a muscular development of the gluteus, causing 

 a small buttock to project over each tuber ischii. This structure, with the 

 peculiar expanse (in quadrumana) of the iliac bones, leads to an inference 

 that the gorilla must naturally and with more ease resort occasionally 

 to station and progression on the lower limbs than any other ape. 



The same cause as in the arm, viz., a continuance of a large pro- 

 portion of fleshy fibres to the lower end of the muscles, co-extensive 

 witli the thigh, gives a great circumference to that segment of the 

 limb above the knee-joint, and a more uniform size to it than in man. 

 The relative shortness of the thigh, its bone being only eight-ninths 

 the length of the humerus (in man the humerus averages five-sixths the 

 length of the femur), adds to the appearance of its superior relative 

 thickness. Absolutely the thigh is not of greater circumference at its 

 middle than is the same part in man. 



The chief difference in the leg, after its relative shortness, is the 

 absence of a " calf," due to the non-existence of the partial accumula- 

 tion of carneous fibres in the gastrocnemii muscles, causing that 

 prominence in the type-races of mankind. In the gorilla the tendo- 

 achillis not only continues to receive the " penniform " fibres to the 

 heel, but the fleshy parts of the muscles of the foot receive accessions 

 of fibres at the lower third of the leg, to which the greater thickness of 

 that part is due, the proportions in this respect being the reverse of 

 those in man. The leg expands at once into the foot, which has a 

 peculiar and characteristic form, owing to the modifications favouring 

 bipedal motion being superinduced upon an essentially prehensile, 

 quadrumanous type. The heel makes a more decided backward pro- 

 jection than in the chimpanzee ; the heel-bone is relatively thicker, 

 deeper, more expanded vertically at its hind end, besides being fully as 

 long as in the chimpanzee. This bone, so characteristic of anthropoid 

 afiinities, is shaped and proportioned more like the human calcaneum 

 than in any other ape. The malleoli do not make such well-marked 

 projections as in man ; they are marked more by the thickness of the 

 fleshy and tendinous parts of the muscles that pass near them, on their 

 way to be inserted into parts of the foot. Although the foot be 

 articulated to the leg with a slight inversion of the sole, it is more 

 nearly plantigrade than in the chimpanzee or any other ape. The 

 hallux (great toe, thumb of the foot), though not relatively longer 

 than in the cliimpanzee, is stronger ; the bones are thicker in proportion 

 to their length, especially the last phalanx, which in shape and breadth 

 much resembles that in the human foot. The hallux in its natural 



