264 



ON THE STRUCTURE OF THE SKULL. 



are adjusted by a broad posterior face to the frontals at Na*. 

 The large premaxillaries ascend along the sides of the anterior 

 nasal aperture to the nasal bones, but are almost excluded from 

 the palate, inferiorly, by the maxillaries ; their alveolar portion, 

 however, is very large and long, and this circumstance, together 

 with the shortness of the nasal bones, throws the anterior nares, 

 in the dry skull, almost to the top of the head. As the palatine 

 processes of the maxillaries and palatines are, at the same time, 

 relatively short, the posterior nares are situated but little behind 

 the anterior nares, and thus the axis of the nasal passage forms 

 a large angle with the basi-cranial axis. The lachrymal is a very 

 small, though distinct, bone. 



In the foetal Elephant here described the space between the 

 two tables of the skull is moderate, and is filled with a spongy 

 diploe ; but, with advancing age, the interspace between the 

 tables in the frontal, parietal, and supra-occipital increases until 

 it equals or exceeds the depth of the cranial cavity, and the 

 diploe is replaced by vertical plates and pillars of bone, between 

 which air-cavities extend back from the frontal sinuses and 

 nasal passages. The skull of the Elephant resembles that of 

 the Pig in many of its most important and characteristic features, 

 and, through the Pig, its affinities are traceable to the other 

 Ungulata. Of these, the skull of the Tapir resembles it most in 

 some respects, such as the shortness of the nasal bones and of 

 the palate ; the consequent large angle w r hich the axis of the 

 nasal passages makes with the basi-cranial axis ; and the pro- 

 longation downwards and forwards of the frontal bones. 



Fig. 104. 



\Pa 



SO 



'HO 



Fig. 104. — Side view of the skull of a Calf. — prnd, the paramastoid process of the 



ex-oecipital. 



