220 SPECIAL SENSES. 



dered nerve-fibres pass each one through a bipolar cell, these 

 cells together forming a spiral ganglion, known as the gan- 

 glion of Corti. Beyond this ganglion, the nerves form an 

 anastomosing plexus, and finally enter the quadrilateral canal, 

 or the canal of Corti. As they pass into this canal, they sud- 

 denly become pale and exceedingly fine, and probably are 

 connected finally with the organ of Corti, though their exact 

 mode of termination has not yet been determined. The 



FIG. 17. 



Distribution of the cochlear nerve in the spiral lamina of the cochlea (the cochlea is from the 

 right side, and is seen from its antero-inferior part). 1, trunk of the cochlear nerve ; 2, 2, 2, 

 membranous zone of the spiral lamina ; 3, 3, 3, terminal expansion of the cochlear nerve ex- 

 posed in its whole extent by the removal of the superior plate of the lamina spiralis ; 4, ori- 

 fice of communication of the scala tympani and the scala vestibuli. (SAPPEY Traite cFana- 

 tomie, Paris, 1871, tome lii., p. 854.) 



course of the nerve-fibres to their distribution in the cochlea 

 is shown in Fig. 17. 21, Fig. 16, shows the ganglion of Corti, 

 and 23, the point of penetration of the nerve into the canal 

 of Corti. 



Organ of Corti. Of all the parts contained within the 

 bony labyrinth, the organ of Corti possesses the greatest 

 physiological interest ; for it is this organ which is supposed 

 to receive the sonorous vibrations and communicate them di- 

 rectly to the terminal filaments of the auditory nerves. Al- 



