"If the word 'Pongo' be of African origin, it is probably a corruption of the word _Mpongwe_, the name of the tribe on the banks of the Gaboon, and hence applied to the region they inhabit. Their local name for the Chimpanzee is _Enché-eko_, as near as it can be Anglicized, from which the common term 'Jocko' probably comes. The Mpongwe appellation for its new congener is _Engé-ena_, prolonging the sound of the first vowel, and slightly sounding the second. [Illustration: FIG. 10.--The Gorilla (after Wolff).] "The habitat of the _Engé-ena_ is the interior of lower Guinea, whilst that of the _Enché-eko_ is nearer the sea-board. "Its height is about five feet; it is disproportionately broad across the shoulders, thickly covered with coarse black hair, which is said to be similar in its arrangement to that of the _Enché-eko_; with age it becomes grey, which fact has given rise to the report that both animals are seen of different colours. "_Head._--The prominent features of the head are, the great width and elongation of the face, the depth of the molar region, the branches of the lower jaw being very deep and extending far backward, and the comparative smallness of the cranial portion; the eyes are very large, and said to be like those of the Enché-eko, a bright hazel; nose broad and flat, slightly elevated towards the root; the muzzle broad, and prominent lips and chin, with scattered grey hairs; the under lip highly mobile, and capable of great elongation when the animal is enraged, then hanging over the chin; skin of the face and ears naked, and of a dark brown, approaching to black. "The most remarkable feature of the head is a high ridge, or crest of hair, in the course of the sagittal suture, which meets posteriorly with a transverse ridge of the same, but less prominent, running round from the back of one ear to the other. The animal has the power of moving the scalp freely forward and back, and when enraged is said to contract it strongly over the brow, thus bringing down the hairy ridge and pointing the hair forward, so as to present an indescribably ferocious aspect. "Neck short, thick, and hairy; chest and shoulders very broad, said to be fully double the size of the Enché-ekos; arms very long, reaching some way below the knee--the forearm much the shortest; hands very large, the thumbs much larger than the fingers....