THE SKULL. 



25 



hinder and inner walls of the 

 orbit. Here also is the tri- 

 geminal foramen (Fig", ii ;/') 

 through which the A^. t riff em inns 

 and the several nerves for 

 the muscles of the eye pass ; 

 it represents the foramen ovale, 

 for. rohmdum, and the fissura 

 orbitàlis siqierior (sj^henoidal 

 fissure) of the human sphenoid 

 bone. The foramen is some- 

 timeSj especially in young- 

 animals, only a notch, which is 

 completed by cartilage. On 

 account of the relation of this 

 part (Fig. ii p') of the bone 

 to the nerves which pierce 

 it, the whole bone has been 

 named by Stannius the ala 

 magna or tenijwralis of the 

 sphenoid; it has been also 

 looked upon as a bone which 

 contains these elements, as by 

 Duges, who on this account 

 calls it rupéo-ptéréal. 



Fig. 13- 



Ajjjjeiiihiffes of ihe Prootic Bones. 



1. The styloid cartilage. From the cartilaginous portion of the 

 prootic the styloid cartilage runs downwards, backwards, and 

 inwards, and is continued directly into the anterior cornu of the 

 hyoid bone (Figs, ii // and 12 /). 



2. The auditory ossicles. 



a. A thick cartilaginous disc, the operculum (Fig. 12 a), 

 closes the foramen ovale. 



b. To the operculum is attached a bony, club-shaped piece, 

 the columella anris (Fig, I2 «'), which has at its inner, thicker 

 end a cartilaginous epiphysis, the interstapedial ; it lies 

 transversely with the apex directed outwards, and this longer 

 portion is the mediostapedial. 



c. To the apex of the mediostapedial is attached, at an 



