102 The Lije Story of the Fish 



nisms. One is the beautiful and delicate spiral cochlea, in 

 which takes place the actual transformation of sound-waves 

 into nervous impulses. It is attached to a sac-like region 



Figure 13. EARS, FISH AND HUMAN 



On the left is the inner ear of the fish, on the right that of the human. 

 Both possess the three semicircular canals, but the cochlea (C), the organ 

 in which sounds are actually transformed into nerve impulses for the 

 human, is missing in the ear of the fish, being represented only by a 

 process of the sacculus (S) called the lagena (L). This is one of the 

 reasons why many people have doubted that fish hear in the same sense 

 that humans do. (Fish ear from Wiedersheim, Comfarative Anatomy of 

 the Vertebrates^ by permission of the Macmillan Company, publishers. 

 Human ear redrawn from Martin, The Hmnan Body^ Henry Holt and 

 Company.) 



called the sacculus. The other is composed of the three semi- 

 circular canals, connected to another sac called the utriculus, 

 which serves to keep us standing upright and going straight 

 ahead. Our ear, therefore, has two functions, hearing and 

 equilibration (Figure 13). 



