204 THE SKULL. [CHAP. 



an animal about six months old, see Fig. 63), their formation 

 has scarcely commenced, and as the sutures are still quite 

 distinct, and the bones not distorted by these cellular 

 dilatations, they are in a much better state for studying 

 their connections and characteristics. 



When the basicranial axis is placed in a horizontal position, 

 it will be seen that the foramen magnum is quite posterior, 

 and its plane nearly vertical. The cranial cavity is elongated 

 and depressed (more so in the African than the Indian 

 Elephant), the tentorial plane nearly vertical, so that the 

 cerebellar fossa is altogether behind the cerebral fossa. The 

 latter is broad behind and contracted laterally in front. The 

 olfactory fossa is large, and placed altogether below the 

 anterior part of the cerebral fossa, the cribriform plate being 

 nearly horizontal. The ridge which separates the anterior 

 from the posterior division of the cerebral fossa is very well 

 marked. The pituitary fossa is very shallow, and there are 

 no distinct clinoid processes. The supraoccipital (SO) is 

 high, and inclines greatly forwards ; so that the occipital sur- 

 face looks upwards as much as backwards. In the adult skull 

 (Fig. 64) the lateral parts of the occipital region (rounded 

 smoothly off in the young state) are vastly expanded and 

 leave between them a deep median depression, with a rugged 

 floor, and a partial bony septum at the bottom, into which 

 the ligamentum nuchae is inserted. The median portion of 

 the supraoccipital never becomes expanded by air-cells. 

 The parietals (Pa) are very large, and form the greater part 

 of the lateral walls of the cranium. The frontals (Fr) are 

 narrow from before backwards, and produced laterally into 

 elongate supraorbital processes, which send out small post- 

 orbital processes, not, however, completely separating the 

 small orbit from the large and high temporal fossa. 



