( 530 ) 
*ig. a. 
Mycetes. (%) Angle of inclination of the For. magn. 59°. 
Mycetes occupies a foremost place in the variability of the inclination 
as m that of the position of the Foramen magnum for reasons 
fully given in the previous paper. For the other skulls, however, 
the same holds good. Another cause of the individual variations is 
the striking difference in sagittal measurement of the For. magnum 
especially in Anthropoids. In the Orang-outang skulls, for instance, 
which I used, this measurement varied from 25 to 41 mm. 
Nevertheless, in spite of these individual variations some remarkable 
eatures are to be detected between the different primate-genera, 
especially if the series be compared as a whole with one another. 
It is noticeable that Chrysothrix does not seem to occupy the place 
attributed to this family in the literature on this subject. Among the 
Flathyrlnnes, Cebus, and more especially Ateles, have greater angles, 
that is to say, in these genera the For. magn. lies more horizontally. 
In this respect the Chrysothrix is inferior even to most of the families 
ot the Catarrhines. On an external observation, however, the For. 
naagn. seems in this monkey’s skull to lie horizontally in consequence 
ot the enormous development of the occiput, and the large share 
that the squama occipitalis occupies in the formation of the cranial 
base. (See Fig. 4). 
