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 caecum 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 
“‘]ong-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 ilii,” 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 differentiation 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. pl. 13. fig. 2. 
