32 
boundary of the external opening, it again appears upon the exterior 
surface of the face above the nostril, where its upper extremity forms 
a triangular or wedge-shaped flattened piece, interposed between 
the lower half of the os nasi and the os mazillare superius, thus ex- 
cluding the latter bone from the boundary of the external nostril. 
One skull of a young Troglodytes niger with deciduous teeth in place, 
shows by the still persistent upper half of its facial suture, that it 
terminates in a point a little above the middle of the border of the 
external nostril, and that a portion of the superior maxillary is in- 
terposed between it and the nasal: in two other skulls of young 
Troglodytes niger, the slender pointed summits of the premaxillaries 
reach the nasals and exclude the maxillaries from the boundary of 
the nostril, but do not expand into triangular plates as in Troglodytes 
Savagei: in not any of the skulls of Troglodytes niger with the per- 
manent dentition does any trace of the suture between the premax- 
illaries and maxillaries remain *. 
The nasal bones of the Troglodytes Savagei also afforded a re- 
markable specific character: although the traces of their primary 
median division were obvious at their lower part, they had coa- 
lesced with each other as in the smaller species; but instead of 
being flat, or slightly and equably convex on the anterior surface, 
as in Troglodytes niger, they are produced forwards as they incline 
towards each other, along their upper half, and project there in the 
form of a slight bony longitudinal ridge, equally dividing the lower 
half of the interorbital space. This character—the nearest approach 
to the prominent nasal bones of Man made by any known species of 
ape—is as well-marked in the female Troglodytes Savagei as in the 
male. The lower half of the coalesced nasals in Troglodytes Savagei 
is expanded and nearly flat, of an oval form, with the border forming 
the upper part of the nostril emarginate on each side of a median, 
sometimes bifid, point. Thus the lateral border of the nasal bone 
describes a strong sigmoid curve, convex outwards in its lower two- 
thirds, in Troglodytes Savagei; in the less expanded nasal bone of 
Troglodytes niger the same border is usually concave outwards, or 
very slightly convex outwards at the lower third; and the outer 
surface of the bone is flat or equably and very slightly convex. The 
greater breadth of the lower end of the nasal with the expansion of 
the upper ends of the premaxillaries, gives a different form to the 
external nostril in the Troglodytes Savagei to that which it presents 
in Troglodytes niger: in this it is ovate or cordate with the narrow 
end upwards; in the larger species it is a wide ellipsoid, almost as 
broad above as below. 
The alveolar portion of the premaxillaries in Troglodytes Savagei 
was absolutely shorter than in Troglodytes niger, and therefore 
much shorter relatively, and to that extent the skull of the larger 
species is less ‘prognathic.’ The zygomatic processes were not 
* M. de Blainville, describing the osteology of the chimpanzee from a young 
specimen of the J'roglodytes niger, says, ‘‘ Mais les prémaxillaires, qui offrent la 
particularité de toucher a peine les os du nez et de souder de fort bon heure avec 
les maxillaires,” &c. Ostéographie, fase. i. p. 33. 
