CHAPTER V 

 HEARING IN FISH 



Hitherto, very little has been said about hearing in fish, and the 

 function of the eighth or auditory nerve ; most people will not be 

 surprised by these omissions, and the more knowledgeable among 

 them would say, fishes cannot hear they only perceive vibrations ; 

 this, however, is not correct, as accurate anatomical investiga- 

 tions supported by the most convincing physiological experi- 

 ments have proved that many fish have a wide range of hearing 



/b.SC 



Fig, i. — Two drawings of the ear of Herring from specimens prepared 

 by the author, and internal ear of man after Schafer. 



S.C.C. — Semi-circular canals. H.S.C.C. — Horizontal semi-circular canal. AMP. — 

 Ampullae, c.c. — Canal of cochlea, e.s.c. — External Canal, s.e. — Saccus 

 endolymphaticus. 



and that the minnow can recognise notes of as wide a range as can 

 the human ear. The ear of a fish can be best understood by a 

 reference to the two diagrams which compare the general structure 

 of the internal ear of a tyj)ical fish with the human ear. 



The lettering which accompanies these diagrams wUl be sufficient 

 to make clear all that is essential for the reader to understand for 

 our present purpose. But there are many fish that have an accessory 

 organ, in addition to those parts of the organ of hearing, known as 

 the saccule and utricle with its three semicircular canals. We should 

 expect that these fishes would be provided with a more speciahsed 

 centre in the brain, and, therefore, before studying the central 

 connections of the auditory nerve, it would be wise to consider the 

 nature of these accessory organs. In pursuit of this idea we are led 



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