256 PROFESSOR OWEN ON THE EXTERNAL CHARACTERS 
The scapule 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 the 
Gorilla they bend forward, so as to produce a pelvic concavity ; and in no other Ape are 
they so broad in proportion to their length as in the Gorilla. In Troglodytes niger and 
Pithecus Satyrus® the iliac bones are flat, or present a concavity rather at the back than 
at the fore part. 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 pro- 
portion to the upper limbs than in the Chimpanzee; they are much longer in that 
proportion and more robust than in the Orangs or Gibbons. But the guiding-points of 
comparisons here are the heel and the hallux. 
The heel in the Gorilla makes a more decided backward projection than in the 
Chimpanzee‘; the heel-bone is relatively thicker, deeper, more expanded vertically at 
its hind end, besides being fully as long, relatively, as in the Chimpanzee. 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 in the 
Gorilla, it is more nearly plantigrade than in the Chimpanzee. The Orang 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 differ- 
entiates the foot from the hand, and gives the character to the order Bimana. 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, itis a true thumb, by position, 
diverging from the other toes, in the Gorilla, at an angle of 60 degrees from the axis of 
the foot’. 
Man has twelve pairs of ribs ; the Gorilla and Chimpanzee have thirteen pairs ; the 
Orangs have twelve pairs; the Gibbons have thirteen pairs. Were the naturalist to 
trust to this single character, as some have trusted to the cranio-facial one, and in 
equal ignorance of the real condition and value of both, he might think that the 
Orangs (Pithecus) were nearer akin to Man than the Chimpanzees (Troglodytes) are. 
* Memoir, No. VII. pl. 1. ?' Ib. pl. 6. * Memoir, No. I. Trans. Zool. Soc. vol. i. pl. 50. 
* Compare Memoir, No. I. pl. 49, with Memoir, No. VII. pl. 13. fig. 2. 
* Memoir, No. VII. pl. 11. fig. 2. 
