264 



ON THE RELATIONS OF MAN 



GOBXLLA. 



CYSTOCEPHALUB 



MYCETE8. 



LEMUR, 



FIG. 16. Sections of the skulU ol .'via a and various Apes, drawn so as 

 to give the cerebral cavity the same length in each case, thereby 

 displaying the varying proportions of the facial bones. The line b 

 indicates the plane of the tentorium, which separates the cerebrum 

 from the cerebellum ; d, the axis of the occipital outlet of the skull. 

 The extent of cerebral cavity behind c, which is a perpendicular 

 erected on b at the point where the tentorium is attached posteriorly, 

 indicates the degree to which the cerebrum overlaps the cerebellum 

 the space occupied by which is roughly indicated by the dark 

 hading. In comparing these diagrams, it must be recollected, that 

 figures on so small a scale as these simply exemplify the statements 

 in the text, the proof of which is to be found in the objects them- 

 selves. 



