566 COMPARATIVE PHYSIOLOGY. 



whole of the end-organ concerned iu hearing is hathed by endo- 

 lymph ; and that the vibrations of the latter are originated by 

 corresponding vibrations of the perilymph, which again is sent 



Fio. 412.— Photographic diagram of labyrinth (after Flint and Efldinger). Upper fig- 

 ure: 1, utricle; 2, saccule; 3,5, membranous cochlea; 4, canalis reaniens; 6, semi- 

 circular canals. Lower figure: 1, utricle; 2, saccule; 3,4,6, ampullae; 5,7,8,9, 

 semicircular canals; 10, auditory nerve (partly diagrammatic); 11. 12, 13, 14, 15, dis- 

 tribution of branches of nerve to vestibule and semicircular canals. 



into oscillation by the movements of the stapes against the 

 membrane covering the fenestra ovalis ; so that the vibrations 

 thus set up without the membranous labyrinth are trans- 

 formed into similar ones within the vestibule and the scala , 

 vestibuli, and end, after passing over the scala tympani, against 

 the membrane of the fenestra rotunda. The cochlear canal 

 may be regarded as the seat of the most important part of the 



