33 
only absolutely as well as relatively stronger and deeper than in 
Troglodytes niger, but differently shaped; the squamosal portion 
rising in an angular form in Troglodytes Savagei, and being as deep 
as the malar portion. ‘The temporal fossz are relatively as well as 
absolutely wider ; for whilst the zygomatic arches are more expanded, 
the diameter of the intervening postorbital part of the cranium is the 
same in the male Trogl. Savagei as in the Trogl. niger. ‘There is a 
distinct hemispheric mastoid process in the male Troglodytes Savagei. 
The spheno-maxillary fissure is narrower and less bent in Troglodytes 
Savagei than in Troglodytes niger, in which it more nearly resembles 
that of Man. The supraorbital ridges were even proportionally more 
developed in the larger than in the smaller species of chimpanzee, 
and send down a vertical prominence to the root of the nasal bones. 
The outer and lower borders of the orbits, and the whole malar bones 
are more prominent and tumid, and, with the enormous sagittal and 
lambdoidal crests and zygomatic arches, give a scowling and dia- 
bolical physiognomy even to dry bones of the head of this most for- 
midable of the great Anthropoid apes. 
In the skull of the female of the Troglodytes Savagei in which 
the canine teeth show the same sexual inferiority of size as in the 
female Troglodytes niger, the molar teeth present the same superior 
degree of development and complexity, especialiy the last molar, as 
in the male of the larger species, and have demanded a concomitant 
increase of bulk of the temporal muscles ; and consequently not only 
are the zygomatic arches relatively stronger, but the temporal ridges, 
instead of being separated as shown in an aged skull of the female 
Troglodytes niger in the museum of the College of Surgeons, by a 
smooth tract of more than an inch in breadth, come into contact 
at the beginning of the sagittal suture, and are so continued back- 
wards with a narrow groove between them, to the lambdoidal crest. 
The development of this crest also renders the supraoccipital sur- 
face almost fiat in the female Troglodytes Savagei, and it is even con- 
cave in the great males; whilst in both adult males and females of 
the Troglodytes niger it is convex. 
There are specific distinctions in the interior of the cranium of 
the two species: the olfactory (rhinencephalic) fossa closed by the 
cribriform plate, though very little wider, is considerably deeper in 
Troglodytes Savagei than in Troglodytes niger ; and the ‘ crista galli,’ 
which is small in Troglodytes niger, is absent in Troglodytes Savagei, 
nor is there any ridge continued from the fossa upon the inner sur- 
face of the frontal in the line of the frontal suture. 
' In Troglodytes niger there is a short ala minor sphenoidei continued 
outwards from the anterior clinoid process, and the upper and outer 
angle of the foramen lacerum anterius is produced into a short cleft : 
in Troglodytes Savagei the rudiment of the ala minor terminates at 
the upper border of the foramen lacerum anterius, which has a sub- 
quadrate form, and is not extended outwards into an angular fissure. 
The sella turcica is relatively shallower in Troglodytes Savagei than 
in Troglodytes niger, it which it is shallower than in Man. 
Many other minor differences were noted, but these would be 
No. CLXXXII.—Procrzpines or THE ZooLogicaL Society. 
