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 proporiiou 

 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 vertebr3e ; in the Gorilla it extends to that between 

 the vertebrae answering to the fourth and fifth lumbars ; but in Man the humeral 

 condyles hang nearly two inches above the iUac 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 lower end. 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 feei 8 inches ; in the Irish 

 Giant ' it is 3 feet 2\ inches. 



In the side view (PI. XIII.) the single curve of the true vertebra;, 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 vertebrae, 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 1 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 stifily 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, 



' Mus. Coll. Chir , Osteol. Ser., No. 5905. 

 VOL. V. — PART I. E 



