THE SENSES 



133 



h.c. 



The other two run in the vertical planes indicated in the 

 diagram, the anterior being called the superior canal (s.c.), 

 and having its ampulla in front, the posterior (p.c.) having 

 its ampulla behind. They join 

 together, and enter the vestibule 

 by a common orifice. 



The bony labyrinth is filled 

 with a lymph-like fluid, the peri- 

 lymph, and in it lies a complex 

 membranous bag, the membranous 

 labyrinth. FIG> 7a _ The Ke i ationship of the 



In the vestibule this is divided Semicircular Canals to one 



into two little sacs, the utricle 



and the saccule, joined together 



by a slender canal. From the 



saccule comes off a canal which runs into the cochlea 



upon the basilar membrane, forming a middle channel 



between the other two, the scala media or membranous 



p.C. 



another. h.c., horizontal 

 canal ; s. c. , superior canal ; 

 p.c, , posterior canal. 



FIG. 71. Transverse Section through one turn of the Cochlea to show the Organ of 

 Corti on the Basilar Membrane. S. M. , scala media ; S.V., scala vestibuli ; 

 S. T. , scala tympani. 



cochlea. This terminates blindly at the apex. From the 

 utricle a membranous canal extends into each of the bony 

 semicircular canals, being provided with an ampulla, which 



