THE SENSE OF HEARING 



413 



diameter of, the bony canals; the ampullae, however, 

 are relatively large. Two small masses of calcium 

 carbonate are found in the utricle and saccule. They 

 are called the otoliths. 



In the cochlea the membranous labyrinth is repre- 

 sented by the scala media and the parts therein 



THE ORGAN OF CORTI. It extends the entire length 

 of the cochlea. It consists of two modified epithelial 



FIG. 145 



Organ of Corti. Diagrammatic view of a small portion. (Testut.) 



cells resting upon a basement membrane and joined 

 above to form an arch which encloses a tunnel or 

 canal of Corti; it also consists of a series of columnar 

 epithelial cells with hair-like processes (hair cells) 

 which rest upon and are supported by the rods both 

 on the inner and .outer side. Other cells lie adjacent 

 to the hair cells, and are supportive in character; 

 these are called Deiters' cells. 



The rods of Corti are very numerous, reaching 

 up into the thousands. The hair-like processes 



