476 



THE CAT. 



[CHAP. xm. 



If we examine the basis cranti of a bear (Fig. 193) we see that its 

 auditory bulla consists of a single bone, instead of two as in the cat. 

 It is but little prominent, but is much prolonged outwards as the 



Fig. 193. PART OF BASIS CRANII OP BEAR (Flower). 



a. Posterior opening of ali-sphenotd canal. 



a'. Anterior opening of same canal. 



c. Condyloid foramen. 



car. Carotid foramen. 



e. Eustachian canal. 



Immediately above the right-hand end of the 

 line leading from the letter e, is a large 

 opening the foramen lacerum anterius 

 at which the carotid artery reappears, after 

 having traversed the petrosal, and bending 



round the skull to re-enter the skull at this 



foramen. 



g. Glenoid foramen. 

 I. Foramen lacerum posterius. 

 m. Mastoid process. 

 ma. Meatus auditorial externus. 

 o. Foramen ovale. 

 p. Par-occipital process, 

 s. Stylo-mastoid foramen. 



floor of the bony meatus auditorius externus (ma). Towards its 

 hinder inner end is a considerable foramen (car) for the internal 

 carotid artery, which here enters the petrosal, and having traversed 



