164: 



SPECIAL SENSES. 



communicating with the tympanic cavity by the f enestra ova- 

 lis, which is closed in the natural state by the base of the 

 stapes. This is the central ovoid opening shown in Fig. 13. 

 The inner wall of the vestibule presents a small, round de- 



. 13. 



The left bony labyrinth of a new-born child, forward nnd outward view. 1, the wide cnnal, the 

 beginning of the spiral canal of the cochlea ; ?. the fenestra rotunda ; 3, the second turn 

 of the cochlea; 4. the final half-turn of the cochlea; 5, the border of the bony wall of the 

 vestibule, situated between the cochlea and the semicircular canals; 6, the superior, or 

 sagittal semicircular canal ; 7, the portion of the superior semicircular canal bent outward ; 

 8. the posterior, or transverse semicircular canal ; 9. the portion of the posterior connected 

 with the superior semicircular canal ; 10, point of junction of the superior and the poste- 

 rior semicircular canal; 11, the ampulla ossea externa; 12, the horizontal or external 

 semicircular canal. (RUDINGER, Atlas des mewchlichen Gehdrorganes. Miinchen, 1867, 

 Lieferung i., Tafel v.) The explanation of this Figure has been modified and condensed from 

 Kudinger. 



pression, the fovea hemispherica, perforated by numerous 

 small foramina, through which pass nervous filaments from 

 the internal auditory meatus. Behind this depression, is the 

 opening of the aqueduct of the vestibule. In the posterior 

 wall of the vestibule, are five small, round openings leading 

 to the semicircular canals, with a larger opening below, lead- 

 ing to the cochlea. 



