OPE eS 
OF THE ORANG UTANS. 169 
The teeth in the jaws of a quadrumanous cranium may be known to belong to the 
permanent series, not only by their size and shape, but by the absence of the foramina, 
which, in an immature cranium, are situated behind the deciduous teeth, and which lead 
to the cavities containing the crowns of the permanent teeth. The character afforded by 
these foramina is well displayed on comparing together the cranium of the Simia Morio 
with one of a young Simia Satyrus, in which the deciduous teeth are present together 
with the first permanent molares. The deciduous teeth in the young Orang, besides their 
smaller size, have their fangs more or less protruded from their sockets, and they are 
thrust apart from one another by the interposition of the osseous particles which are 
deposited to enlarge the jaw for the lodgement of their large successors ; while in the 
Stmia Morio the teeth are lodged firmly in the jaws, and with the exception of the charac- 
teristic interval between the canines and incisors in the upper jaw, and the canines and 
bicuspides in the lower jaw, are compactly arranged in close contiguity with each 
other. 
That the cranium of the Simia Morio here described, belonged to an adult, is proved 
by the small interval between the temporal ridges at the crown of the skull, corresponding 
to the extensive surface of origin of the crotophyte muscles ; and by the obliteration of 
the intermaxillary sutures: that it belonged also to an aged individual is highly pro- 
bable from the extent to which the teeth are worn down, and from the obliteration, 
notwithstanding the absence of interparietal and lambdoidal crests, of the sagittal and 
lambdoidal sutures. 
The cerebral portion of the skull of Simia Morio equals in size that of the Pongo, and 
indicates the possession of a brain at least as fully developed as in that species, while 
the maxillary portion is proportionally smaller ; so that, as the cranium rises above the 
orbits, and is, like that of the Pongo, more convex on the coronal aspect than in the 
Chimpanzee, and wants the prominent supraciliary ridge which characterizes the African 
species, it presents in the Simia Morio altogether a more anthropoid character. 
There are, however, the rudiments of the ridges which so remarkably characterize 
the cranium of the mature Pongo. Those which commence at the external angle of the 
frontal bone pass backwards, upwards, and slightly converge, but do not meet; they 
gradually diminish in breadth, and, after passing the coronal suture, subside to the level 
of the skull ; they are then only traceable by a rough line, which leading parallel to the 
sagittal suture, and gradually bending outwards, rises again to be continued into the 
lambdoidal ridges ; thus circumscribing the origins of the temporal muscles. The 
lambdoidal and mastoid ridges are broader and more developed than in the Chimpanzee, 
but inferior in both respects to those of the Pongo. The inial region of the occiput is 
almost smooth, and is convex, without the mesial ridge, and strong muscular impressions 
observable in the Pongo, where a preponderating weight in front calls for the insertion 
of powerful muscles behind to counterbalance it. 
The temporal bones join the frontal in Simia Morio as in the Troglodytes niger ; but 
