X.] 



CARXIVORA. 



14: 



detached from the cranium in skulls of young animals. Its 

 form is more or less triangular, being broad and nearly 

 straight at the inner edge, and produced outwards into 

 a considerably elongated floor of the external auditory 

 meatus. Its greatest prominence is along the inner border; 

 from this it gradually slopes away towards the meatus. The 

 entrance of the carotid canal is a considerable circular 

 foramen, near the hinder part of the inner edge of the bulla. 

 In old animals it is partly concealed by the prominent lip of 

 the basioccipital, which abuts against the inner edge of the 



Fig. 52. — Section of the left auditory bulla and surrounding bones of a Bear [Ujsiis 

 ferox). Sq squamosal ; T tympani'^ ; BO basioccipital ; am external auditory 

 meatus ; t tympanic ring ; e Eustachian canal ; C^r carotid canal. (From Proc. 

 Zool. Soc 1869.) 



bulla ; and by the growth of this, and the paroccipital pro- 

 cess, it becomes almost included in the deep fossa leading 

 to the foramen lacerum posterius. When a section is made 

 through the auditory bulla (see Fig. 52) it is seen to be a 

 simple thin-walled bony capsule, imperfect above, where it 



L 



