16 DESCRIPTION OF THE SKELETON. 



Above the occipital crest is a blind osseous cavity, uncovered by the 

 breaking of the external table of bone into some of the numerous cells of 

 the cranium. At the inferior part of this surface is the great occipital 

 foramen, wlrich looks from before backwards, and a little obliquely from 

 above downwards. It is three inches and a half in the transverse, and four 

 in the antero-posterior diameter. On each side are the occirjital condyles, 

 projecting two inches on their median lines, and presenting an articulating 

 surface four inches broad and eight long. The posterior face of the head 

 is twenty-two inches high by thirty-two wide. The condyloid portion of 

 the occipital bone is separated in young animals from the supra-occipital 

 by an angular suture, which crosses from the posterior angle of one temporal 

 bone to the other. 



In the young Mastodon head is seen the occipitoparietal suture. It 

 lies midway between the inferior termination of the vertical ridge and the 

 upper edge of the great occipital foramen, extending from this median point 

 in a lateral direction more than half-way on the posterior face ; then at an 

 acute angle turning downwards, and with an inward curve terminating on 

 the outside of the occipital condyle. 

 Lateral Lateral Faces (Large Plate, and Plate XVI.). — The lateral face is. 



separated from the superior by a line which extends from the superior 

 occipital ridge along the superior edge of the temporal fossa to the orbit, 

 thence along the superior orbital ridge, and from the inferior anterior abrupt 

 termination of this ridge forwards through the anterior infra-orbitar fora- 



* 



men to the edge of the tusk-socket. This line is strongly marked and 

 rough at the upper edge of the temporal and of the orbitar fossae, beyond 

 which it is not indicated by any natural mark. 



The temporal fossa is of very great size. It is formed by the parietal, 



Faces. 



