PAPIO ANUBIS. 
39 
skull in its general features is practically a replica of the Abyssinian skulls, but 
the fact that a broad interorbital septum is a feature of the skulls of the baboons of 
this group in West Africa serves in a Avay to link them to those of the Upper White 
Nile and of Dar Fertit h 
The fossa before the malar and on the side of the maxilla is greatly developed, and 
also the external mandibular pit below the first and second premolars and first molar. 
The depth and length of the palate vary, and its length depends much on the age of 
the animal, as Avhen the last molar has travelled forwards to be in front of the base of 
the zygomatic process of the malar, the palate is consequently much longer than in 
skulls less mature. The lateral temporal ridges in the adult define an elongated 
backwardly-pointed V-shaped area, the front of which is marked by the frontal 
depression, and at this period of growth the ridges unite at the hinder extremity 
of the frontal. Young males, as regards the general features of the skull, resemble 
the adult female. In the case of the female the temporal ridges are always widely 
apart anteriorly and posteriorly, and rarely unite, even on the occipital. The maxillary 
and mandibular pits are well marked in the females. 
Matschie was under the impression that the baboon from the Shilluk Islands 
(P. heuglini), the skull of which he stated strongly resembled in its structure the skull 
of P. doguevct, differed from the latter in the shape of its last lower molar. In 
the Shilluk baboons he held that the terminal cusp does not lie in the line of the inner 
cusps, but between the inner and outer cusps of the tooth; but from the figures here 
given (Plates \ ., VI., VII.) there does not appear to be any difference in the position 
or essential characters of this cusp in the skulls of baboons from Abyssinia, the Gash 
Fiver, and Shilluk. 
A leading feature of the skull of P. anubis as compared with the skull of 
P. cynocejghalus is the great prominence and upward and forward projection of its 
superciliary ridges, so that the frontal surface is more depressed and more concave. 
1 In photographing skulls of baboons it is of the utmost importance that they he placed perfectly vertically, 
or at least that a uniform method of representing them be adopted. When a skull is vertically placed, the 
suture formed by the frontal and the malar at the external angle of the orbit should be projected back¬ 
wards by the tilting of the muzzle, so as almost to cover the anterior end of the parietal bone in the temporal 
fossa, and thus reduce what is visible of the broad outlines of the fossa to a small oval space lying between 
the zygomatic and orbital branches of the malar. When the tip of the muzzle is depressed backwards the 
proportions of these parts appear quite altered, and an erroneous impression is given of the character of a 
skull in a series^ if the others have been photographed out of the vertical. 
