OF FISH IN GENERAL. 



Observations by J. Hunter. 



To the ingenious J. Hunter, F. R. S. we are 

 indebted for the following minute description of 

 the organs of hearing in fish: " They are placed 

 on the sides of the skull, or that cavity which. 

 contains the brain; but the skull itself makes no 

 part of the organ, as it does in the quadruped 

 and the bird. In some fish, this organ is wholly 

 surrounded by the parts composing this cavity, 

 which in many is cartilaginous; the skeleton of 

 these fish being like those of the ray kind; in. 

 others also, as in cod, salmon, &,c. whose skeleton 

 is bone, yet the part is cartilaginous. 



" In some fish this organ is in part within the 

 cavity of the skull, or that cavity which also con- 

 tains the brain, as in the salmon, cod, Sec. the 

 cavity of the skull projecting laterally, and form- 

 ing a cavity there. 



" The organ of hearing in fish appears to grow 

 in size with the animal, for its size is nearly in 

 the same proportion with the size of the animal, 

 which is not the case with the quadruped, &c. 

 die organs being in them nearly as large in the 

 the growing foetus as in the adult. 



" It is much more simple in fish than in all 

 those orders of animals who may be reckoned 

 superior, such as quadrupeds, birds, and amphi- 

 bious animals, but there is a regular gradation 

 from the first to fish. 



" It varies in different orders of fish; but in 

 all it consists of three curved tubes, all of which 

 unite with one another : this union forms in 

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