THE AUDITORY APPARATUS 



505 



THE AUDITORY APPARATUS. 



THE organ of hearing admits of a very natural subdivision 

 into three parts, viz., the external, the middle, and the 

 internal ear. 



Auricle 



Epitympanic recess 



Aditus of tympanic antrum 



Lateral semi-circular canal ' 



Superior semi-circular canal 



Vestibule .' 



Internal acoustic 



meatus 



. Concha 



External acoustic meatus 

 Mastoid process 



Styloid process 

 Auditory tube Canal for facial nerve (cut above) 



FIG. 205. The parts of the Ear (semi-diagrammatic). The purple colour 

 indicates the mucous lining of the tympanic cavity, which is continuous, 

 through the auditory tube, with the mucous lining of the pharynx, and, 

 through the aditus, with the mucous lining of the tympanic antrum. 



The external ear consists of the auricle and the ex- 

 ternal acoustic meatus. The auricle collects the waves 

 of sound, and is, comparatively speaking, of subsidiary im- 

 portance in man, although it is of considerable service in 



