170 MR. OWEN ON THE OSTEOLOGY 
this structure occasionally is present on one or both sides of the skull in Sima 
Satyrus. 
The additamentum suture lambdoidalis is present on both sides in the Simia Morio, and 
the beginning of the lambdoidal suture may be faintly traced, but the remainder is 
obliterated. 
Directing our attention to the base of the skull of Simia Morio we observe the occipital 
foramen to be less posteriorly situated than in the Pongo, but more so than in the Chim- 
panzee. The plane of the foramen is also less oblique than inthe Pongo. The occipital 
condyles are as far apart anteriorly as in the Chimpanzee. The anterior condyloid 
foramina are double on each side as in the Pongo: the carotid and jugular foramina 
open within the same depression ; they are relatively further apart in the Chimpanzee : 
the petrous portion of the temporal bone, as in the Pongo, is relatively smaller than in 
the Chimpanzee ; and the articular cavity, or surface for the lower jaw, forms a larger 
proportion of the base of the skull. 
The other characters of the basis cranii correspond with those of the Pongo ; and the 
smaller size of the meatus auditorius externus is probably associated in both species with 
a smaller auricle as compared with the Chimpanzee. 
On the bony palate the relative position of the foramen incisivum corresponds with 
the development of the incisive teeth, showing the intermaxillary bones to be of larger 
size in the Simia Morio than in the Chimpanzee: the situation of the sutures joining these 
bones to the maxillaries is indicated by vascular grooves, but otherwise obliterated ; 
while in the cranium of a young Pongo of nearly the same size as that of the Sima 
Morio, the intermaxillary sutures still remain, corresponding to the non-development of 
the permanent laniaries. It will be interesting to determine at what period these 
sutures are obliterated in the more anthropoid Simia Morio. 
The os nasi is a single narrow long triangular bone, slightly dilated at its upper end 
or apex, with the basal margin entire, presenting no indications of original separation 
into two parts, as has been observed in skulls of the Chimpanzee. 
In the contraction of the interorbital space, and the general form of the orbit and its 
boundaries, the Simia Morio resembles the Simia Satyrus, but the orbital cavity, as 
before observed, is smaller. In the plane of the orbit and straight contour of the 
upper jaw, the Simia Morio resembles the Bornean species of Pongo or Simia Wurmbii, 
rather than the Simia Abelii or Sumatran Pongo. 
The orbital process of the os male is perforated in the Simia Morio as in the Pongo, by 
several large foramina. There are one principal and two very small infraorbital foramina 
on either side ; the upper maxillary bones are relatively smaller, as compared with the 
other bones of the face, and especially the intermaxillaries, than in the Pongo; a 
structure which coincides with the smaller proportional development of the canine 
teeth. The nasal aperture has the same form as in the adult Simia Wurmbiu, being 
more elongated than in the immature Orang. 
