PACHYDERMATA. 



Fig. 470. 



861 



Vertical section of the skull of a young Boar. 



Fig. 471. 



minores almost along their whole length and 

 mask the pterygoid processes, so as to give a 

 very peculiar appearance to the base of the 

 cranium. 



The bones of the face are remarkable for 

 their massive developement, but as their posi- 

 tion is sufficiently indicated in the next wood- 

 cuts, it would be useless to particularize them 

 further. 



Ribs and sternum. The thoracic cavity 

 throughout all the Pachydermatous genera is 

 enormous in proportion to the great bulk and 

 excessive weight of the viscera. The ribs, in 

 fact, are continued backwards almost to the 

 pelvis, and from their extraordinary size and 



Fig. 472. 



Occipital bone of a young Boar, shewing its division 

 into four pieces. 



In the above three figures the parts indicated are 

 as follows : a, a, frontals ; b, b, parietals ; c, c, 

 2, c 2, c 3, occipital ; d, temporal ; e, lateral 

 processes of occipital bone ; f, sphenoid ; g, 

 supra-orbital plate of os frontis ; h, os lacrymale ; 

 i.jugal bone; h, superior maxillary; I, inter- 

 maxillary ; m, nasal ; n, inferior maxilla ; o, 

 ossified nasal cartilage ; p, palatine. 



turbinated laminae are very large, so that the 

 delicacy of the sense with which they are con- 

 nected is evidently only inferior to that of the 

 carnivorous quadrupeds. 



The sphenoid occupies the same position as 

 in the skull of Man, and in the hog tribe is 

 very similar in its shape and the general ar- 

 rangement of its processes to the human. In 

 the Elephant the anterior and posterior clinoid 

 processes are but slightly developed, so that the 

 base of the cranium internally has a very flat 

 appearance, whilst externally, such is the enor- 

 mous developement of the sphenoidal cells, 

 that they stretch on each side beneath the alee 



Skull of A merican Tapir. 

 Fig. 473. 



Skull of Sus Larvatus. 

 Letters as in figure 465. 



