HEARING IN FISH 



43 



to the study of the air-sacs or swim-bladder of fish, and it is found 

 that this organ is capable of presenting a great variety of methods 

 of increasing the auditory function in different families of fish. 



PLATE 6. 



BARBEL 



TH£UMATlC r>UCT 



'SULLET 



Diagram of Fish to show relations 

 of swim- bladder and auditory 

 vesicle to internal ear and dis- 

 tribution of the taste-buds. 





Distribution of taste-buds in Man 

 and relation of air-passages to 

 the middle-ear. 



Black dots signify site of taste-buds. 



The history of the swim-bladder is one of the most remarkable 

 tales in the development of present day fishes. Although the swim- 

 bladder was originally a lung, it is now^ largely used as a hydrostatic 

 organ or buoyancy tank ; nevertheless, there is often a vesicle or 

 secondary air-bag given off from its anterior end, which is connected 

 by various means with the internal ear. The very large family 

 known as the carps or Cyprinoids have a swim-bladder lying free 

 in the upper part of the abdominal cavity only attached to a small 



