72 
THE MAMMALS OF EGYPT. 
The materials which I have examined and herein described leave in my mind no 
dubiety regarding the specific identity of all the animals enumerated. They, however, 
suggest that as this baboon is traced southwards there is a tendency to a greater 
development of yellow pigment over its surface generally, and on the ontsides of the 
hind limbs in particular, than is to be found in baboons occurring in the northern 
area of its distribution, and that the texture of the hairs becomes modified in some 
localities. But in order thoroughly to understand the variations to which this baboon 
is subject between its birth and its adult condition, it would be necessary to bring 
together a very large series of individuals not merely from one troop but from 
different troops, and equally extensive collections from different localities over the 
area of its distribution would have to be made to admit of the geographical and 
individual variations being thorougbly understood. Few would have the courage to 
enter on a wholesale massacre of baboons for such a purpose. I once inconsiderately 
shot a Macaque without killing it outright, and the way in which the poor unfor¬ 
tunate held its hand to its wound and looked at me is a picture still vivid in my 
memory after a quarter of a century. 
The changes which take place in the maxillary region of the skull with advancing 
age are so great that measurements based on the space intervening between the front 
of the incisors and a line joining the posterior border of the last molar and compared 
with a measurement, e. g., such as that between this line and some point of the foramen 
magnum, are misleading, unless the individuals under comparison have been accurately 
ascertained to be of exactly the same age or fully adult. In a skull with its milk- 
dentition, the posterior border of the second premolar may be, and generally is, on a 
line with the anterior border of the posterior palatine foramen, whereas in the adult 
skull the corresponding border of the third molar is on a line with the posterior 
border of that foramen. In the young skull the distance between the incisors and a 
line connecting the second premolars is about equal to or slightly in excess of the 
interspace between such a line and the anterior border of the foramen magnum, 
whereas in the adult skull the distance between the incisor and a line connecting 
the last molar is greatly in excess of the interval between the latter line and the 
foramen magnum. When the first molar appears its posterior border lies some distance 
behind the hinder border of the palate, whereas in adult life the tooth has moved so 
far forwards that its anterior border is opposite to the middle of the palate. Even 
after all the teeth are fully through the jaws they still continue to travel forwards. 
Thus the last molar will be found to have its posterior border lying in a line with the 
anterior root of the zygomatic arch, whereas in an animal with its teeth much worn 
the posterior border of the last molar is a long w'ay anterior to that suture. With 
this forward movement of the jaws is associated the creation of a postdental maxillary 
tract behind the last molar, of varying extent, dependent on the age of the individual. 
