The vertebræ of the neck, back, and loins number the same—seventeen—as in Man; but there are thirteen parts of ribs instead of twelve. The neck-vertebræ have long spines which contribute to the thickness of the neck. The curvature, characteristic of Man, in the lumbar region of the vertebral column of the young Gorilla, is more developed than in the Chimpanzee, and in both are earlier developed than in Man. (Symington.)
The wrist (carpus) contains but eight bones, as there is no central (os centrale) bone, a character in which it agrees with Man and the Chimpanzee, but differs from the Orang.
The volume of the brain in the largest Gorilla rarely exceeds 34½ cubic inches, which is only half the capacity of the human skull. It may be safely said that an average European child, of four years old, has a brain twice as large as that of an adult Gorilla. The weight of a healthy human brain never falls below 31 ounces; that of the largest Gorilla has probably never reached 21. (Huxley.)
In the brain of the Gorilla the cerebellum can be seen between the deep longitudinal fissure which separates the two halves of the cerebrum. It agrees in this with the Orang and Anthropopithecus calvus—the latter exhibiting even a greater divergence of the cerebral lobes.
The young male Gorilla differs much from the adult; its central cranial crest is less prominent than the occipital ridge for the neck muscles.
The female is much smaller than the male, but the cheeks are relatively broader; the cranial crests and ridges are less strongly marked, and the canines shorter and less powerful. Her breasts are long and pointed, not globular.
The height of the adult male Gorilla is over six feet, but the female rarely exceeds four feet six inches.
The general colour of the Gorilla is black or blackish; the whole skin of the face is glossy, set with a few hairs, and deep black; the crown reddish-brown, sometimes of a dark brown, the hairs being dun-coloured at the root, grey in the middle, and dark brown at the tip; on the sides of the face the hair is dark brown or black, grey at the root; on the neck and shoulders the hair is grey at the root, and lighter towards the point. The back, the region of the humerus, and the thighs are brownish, the hair being pale grey at the root, blackish-brown further up, and dark grey at the termination; the fore-arms, the hands, ankles, and feet, dark brown or black; round the posterior is a circle of white hair in some, in others of brownish-yellow. Old individuals become grey or grizzled.
Distribution.—Western Equatorial Africa, between the Cameroons and the Congo. This region presents a variety of hill and dale; the uplands are clothed with forest, and the dales are covered with grass and low bush, with abundance of fruit-yielding trees.
Habits.—This extraordinary animal, round which have gathered so many myths, derived mostly from the inexact and magnified tales of the natives, still further exaggerated by careless or imaginative visitors to the West Coast of Africa, was first brought to the knowledge of science by Dr. Thomas Savage, an American Medical Missionary, in 1847. From that time downwards numerous preserved specimens of the animal have been received in excellent condition, so that its anatomy is very fully known. In 1860 the first living individual reached Europe, and lived for some months in Wombwell's Menagerie. Since that date both English and continental menageries have had specimens in captivity. What we know of the habits of the Gorilla is greatly based on observations made on these captive animals. Abundant statements to the contrary notwithstanding, very few persons, competent to give an intelligent account of their habits, have ever seen the Gorilla alive in its native state. Even now, for our best accounts, we are indebted to Dr. Savage, who obtained most of his information from the natives, whose language and character he understood so thoroughly that he was able to extract from them, by carefully sifting their statements, most accurate information free from exaggeration and conjecture.