Habits and Osteology of a New Orang. 427 
Orang and Chimpanzée form a strong projection below the 
nasal orifice, but are most conspicuous in the former, giving the 
lower part of the face that remarkable degree of prominence 
which is socharacteristic. In the Engé-ena the outline of the 
face is straight from below the superciliary ridges (Pl. I. and IT.) 
to the edge of the incisive alveoli, and when the head is so 
placed that the edge of the lower jaw is horizontal, the facial 
line makes with it an angle of about 45°. The facial angle 
according to the usual method of measuring it (the supercil- 
lary ridges excluded) is about 30". According to Mr. Owen 
that of S. satyrus is 30^, and that of Troglodytes niger 35°.’ 
The most remarkable peculiarity, one which strikes the ob- 
Server at sight, is the great development of the interparietal 
and occipital crests, as well as of the superciliary ridges, 
(PI. I.) all of which give the head great angularity of outline, 
causing it somewhat to resemble that of S. satyrus, and to con- 
trast with that of T. niger, on which there are no crests, and 
the superciliary ridges of which, though well developed, are 
much more curvilinear and smooth. Both crests are quite 
thin on the free edges, and are elevated about 1j inches above 
the skull; the occipital extending across from one mastoid 
Process to the other, and the interparietal extending forward at 
Night angles to it terminates near the centre of the coronal 
Fegion in two strong diverging ridges, which are directed to 
the outer angles of the orbits, including between them a 
*eply concave triangular space. The superciliary ridges are 
much more prominent than in the Chimpanzée, especially at 
their union over the nose, and the apertures of the orbits are 
more nearly square. A single large supra-orbitar and a small 
Ifra-orbitar foramen exists on each side. The two fol- 
ng peculiarities, pointed out by Prof. Agassiz, exist in all 
“© crania, and are specific characters ; one of them is drawn 
m the structure of the infra-orbitar canal, which in the 
panzée forms a deep groove terminating in the spheno- 
! Trans. Zoolog. Soc. London, T. p. 372. 
