AND AFFINITIES OF THE GORILLA. 255 



that the anthropoid intestinal and dermal characters were associated with the absolutely 

 larger and better-developed brain in the Gorilla, Chimpanzee, and Orang ; whilst the 

 lower quadrumanous characters exhibited by the cfficum and nates were exhibited by 

 the smaller-brained and longer-armed but rounder-skulled and shorter-jawed Gibbons. 



Pursuing the comparison through the complexities of the bony framework, he might 

 first glance at the more obvious proportions, and such, indeed, as would be given by the 

 entire animal. The characteristics of the limbs in Man are their near equality of 

 length, but the lower limbs are the longest. The arms in Man hang down to below the 

 middle of the thigh ; in the Gorilla they attain the knee ; in the Chimpanzee they 

 reach below the knee ; in the Orang they touch the ankle ; in the Siamang they reach 

 the sole ; in most Gibbons the whole palm can be applied to the ground without the 

 trunk being bent forward beyond its naturally inclined position on the legs. These 

 gradational differences coincide with other characters determining the relative proximity 

 to Man of the Apes compared. In no Quadrumana does the humerus so much exceed 

 the ulna in length as in Man ; only in the most anthropoid, viz. the Gorilla and Chim- 

 panzee, does it at all exceed the ulna in length ; in the rest, as in the lower quadrupeds, 

 the fore-arm is longer than the arm. 



The humerus, in the Gorilla, though less long, compared with the ulna, than in 

 Man, is longer than in the Chimpanzee ; in the Orang it is shorter than the ulna ; in the 

 Siamang and other Gibbons it is much shorter : the peculiar reach of grasp in those 

 " long-armed " Apes is chiefly due to the excessive length of the antibrachial bones. 



The difference in the length of the upper limbs, as compared with the trunk, is but 

 little between Man and the Gorilla. The elbow-joint, in the Gorilla, as the arm hangs 

 down, is opposite the " labrum ihi," the wrist opposite the " tuber ischii" ' ; it is rather 

 lower down in the Chimpanzee ; it is opposite the knee-joint in the Orang ; it is oppo- 

 site the ankle-joint in the Siamang. 



Man's perfect hand is one of his peculiar physical characters : that perfection is 

 mainly due to the extreme diflferentiation of the first from the other four digits, and 

 its concomitant power of opposing them as a perfect thumb. A partially opposable 

 thumb is present in the hand of most Quadrumana, but it is usually a small appendage 

 compared with that of Man. Small as it is in the Gorilla, it is relatively largest in that 

 species. 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 zoologist 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. 



' Memoir, No. VII. pi. 13. fig. 2. 



