
THE CHIMPANZEE AND ORANG UTAN. 347 
angle of the temporal joins the frontal and separates the parietal from the sphenoid 
bones, as in six out of seven skulls of the young Chimpanzee which I have examined. 
The frontal bone extends to the middle of the coronal surface of the cranium ; 
the parietals occupy the remainder of that aspect ; the squamous portion of the oc- 
cipital bone, which in the young Chimpanzee encroaches for a small extent upon the 
coronal surface, is in the adult wholly confined to the inial or posterior region of the 
skull: it is, however, of considerable extent, and more convex than in the Orang, 
and consequently more like that of the human subject'. The squamous portions of the 
temporal bone extend over a much less proportion of the sides of the cranium than in 
Man ; and their superior margin, instead of forming a convex curve, is almost a straight 
_line. The mastoid processes are represented on either side by a mere ridge of bone, 
and the styloid processes by small tubercles. The condyloid processes of the occipital 
bone are proportionally smaller than in the human subject. The foramen magnum, in- 
stead of being placed immediately behind the middle transverse line of the skull, as in 
Man, is situated in the middle of the posterior third of the basis crani, and its plane 
is inclined upwards from the anterior margin at an angle of 5° from the plane of the 
basilar process. There are no posterior condyloid foramina, but the anterior condyloid 
foramina, the foramina jugularia, stylomastoidea, carotica, spinosa, and ovalia, are in 
nearly the same relative positions as in Man ; the principal difference is in the greater 
distance between the foramen caroticum and the foramen ovale, in consequence of the 
greater antero-posterior extent of the petrous bone. 
In consequence of the proximity of the foramen magnum to the posterior margin of 
the skull, a considerable extent intervenes between it and the posterior margin of the 
bony palate ; this is occupied by the before-mentioned development of the petrous bones, 
and a corresponding extent of the basilar element of the occipital. The antero-poste- 
rior diameter of the bony palate in like manner greatly exceeds that of the correspond- 
ing part of the human skull. The zygomatic arches are opposite the middle third of 
the skull, as seen from below, while in the human cranium they are included in the 
anterior moiety. The form of the basis cranii differs generally from the Bimanous 
and manifests the Quadrumanous type, in its greater length, in its flatness, in the small 
extent of cranium behind the foramen magnum, in its contraction between the zygomata, 
and in the large size and especially the anterior development of the bony palate. 
The front view of the skull of the Chimpanzee impresses the spectator still more 
strongly with its resemblance to that of the Baboon and the inferior tribes of Quadru- 
mana. ‘The superciliary ridges of bone almost hide the cranium from view ; and the 
cranial mass, instead of forming a broad back-ground to the face, asin the young 
Chimpanzee, and as it does in a still greater degree in Man, is surpassed in breadth 
} In two skulls of the young Chimpanzee I have observed an os triquetrum at the junction of the sagittal with 
the lambdoidal suture. Dr. Traill notices a similar circumstance in the young Chimpanzee dissected by him. 
(Wernerian Transactions, vol. iii, p. 10.) 
