THE CHIMPANZEES AND ORANGS. 25 
5 feet 6 inches, in as erect a position as it can naturally be brought, the length of the 
trunk is 3 feet. From the vertex to the ischial tuberosities in the Man measures 3 feet ; 
in the Gorilla it measures only 3 feet 5 inches, owing to the inferior height of the 
cranium, even with the parietal crest fully developed. The similarity of proportion 
of the upper limb to the trunk, in length, is due mainly to the greater proportional 
length of the pelvis in the Gorilla. The humerus in Man extends as low as the interspace 
between the third and fourth lumbar vertebre ; in the Gorilla it extends to that between 
the vertebre answering to the fourth and fifth lumbars; but in Man the humeral 
condyles hang nearly two inches above the iliac labrum, while in the Gorilla they extend 
as far below that labrum. ‘The tips of the fingers in Man, when he stands erect, usually 
reach to the middle of the femora; in the Gorilla they reach to about an inch from 
the lowerend. The length of the bones of the upper limb in the Human skeleton (PI. XII. 
fig. 1) is 2 feet 9 inches ; in the Gorilla (ib. fig. 2) it is 3 feet 8 inches; in the Irish 
Giant’ it is 3 feet 24 inches. 
In the side view (Pl. XIII.) the single curve of the true vertebre, especially if carried 
along the tips of the spinous processes, strongly differentiates the skeleton of the Ape 
from that of Man; but this, in the Gorilla, is due in part to the enormous length of 
the spines of the cervical vertebre, especially of the lower five: along the fore part of 
the true vertebra, there is a slight convexity at the cervical and lumbar regions, but 
of less extent longitudinally than in Man. After the seventh vertebra, counting down- 
wards, thirteen pairs of pleurapophyses are developed as free, moveable ribs, in the 
Gorilla; and they are relatively longer, thicker, broader, and with minor intercostal 
spaces, especially behind, than in Man. The first seven pairs reach the sternum by 
their cartilages, as in Man, the supernumerary pair being developed from the segment 
answering to the first lumbar in Man. The fore-and-aft diameter of the bony thorax 
at the fore end of the eighth rib, in the medium state of respiration, in the Gorilla, 
is 1 foot 1 inch; in Man it measures 7 inches. The transverse diameter of the 
bony chest, under the same circumstances, in the Gorilla, at the ninth pair of ribs, 
is | foot 2 inches; in Man it is 9} inches. The length or vertical extent of the bony 
thorax in the Gorilla is 1 foot 5 inches, in Man it is 1 foot 2 inches. Estimating 
the volume of the entire cavity of the thorax in the Human skeleton figured in Plates 
XII. and VIII. at 330 cubic inches, that of the Gorilla would be about 500 cubic inches ; 
but the vital capacity, or measure of the mobility of the chest, does not differ in the same 
degree,—that in Man, through the lighter character of the thoracic compages, being 
proportionally greater than in the more strongly and stiffly girt thorax of the great 
Ape. ‘The superior absolute capacity or area of the chest in the Gorilla is in harmony 
with its superior muscular development and the exercise of greater force in that animal. 
The breast-bone, though one-third longer than that of Man, is relatively broader, 
* Mas. Coll. Chir., Osteol. Ser., No. 5905. 
VOL. V.——PART I. E 
