OUR FACE FROM FISH TO MAN 



shark (Fig. 6) and the lateral line organs in the 

 skin of most fishes. These organs are sensitive 

 to the disturbances caused in the water either by 

 wind or by objects falling on the surface of the 

 water (G. H. Parker). Below the semicircular 

 canals there is a sac-like depression (Fig. 104 A) 



Fig. 105. Development of the Labyrinth or Inner Ear of 

 Man (after Streeter). 



frequently containing an otolith or calcareous 

 secretion which may function in the sense of bal- 

 ance. The nerve that goes to the semicircular 

 canals also sends off a branch which is attached 

 to the otolith, and this lower branch, in the higher 

 vertebrates, is the nerve of hearing (Fig. 104D-F). 

 It is doubtful whether fishes can really hear 

 rather than feel sound waves in the water. The 

 true organ of hearing equivalent to the cochlea of 



man has its inception apparently in the Amphibia 



206 



