336 PHILOSOPfTV' OF ZOOLOGY. 



in number, and are hard and white like porcelain. In the 

 cartilaginous fishes with three branchiae, these bodies are 

 in general fewer in number, and of a softer consistence, 

 being seldom harder than moistened starch'. It is supposed 

 that these bodies assist in communicating to the nerves the 

 vibrations produced in the water by sound. With the sac 

 are connected three semicircular canals, filled with a viscid 

 fluid, similar to that in the large sac. The auditory nerves 

 arise so near to the origin of the fifth pair, that they have 

 been considered as the same. In the genus Raja these pass 

 into the cavity of the ear, by a particular foramen ; in the 

 osseous fishes, they are distributed directly into that organ. 



As the ear of fishes is much less complicated in its struc- 

 ture, than in the higher orders of animals, we may con- 

 clude, that the sense of hearing is weak in proportion. In- 

 deed, the difficulty of detecting any natural movements of 

 fishes, occasioned by sound, led the ancients to conclude 

 that they did not enjoy this sense. In ichthyology, the 

 characters of the organs of hearing are too minute and dif- 

 ficult of detection, ever to be employed. They vary in 

 different species, it is true, and may be resorted to in cases 

 of difficulty ; but for their investigation they require a 

 dexterous hand and an experienced eye. 



As the tongue of fishes (the organ in which the sense of 

 taste resides in the higher orders of animals) is but imper- 

 fectly developed, naturalists are in general disposed to con- 

 clude, that the sense of taste can scarcely be said to belong 

 to this class of beings. It presents no visible distinct pa- 

 pillae, and its skin is analogous to the common integuments 

 of the mouth. The nerves which supply it, are branches 

 of the same nerves which proceed to the branchiae In the 

 present state of our knowledge it is impossible to assign 

 the precise influence which the sense of taste exercises on 

 the economy of fishes. If noxious ingredients exist in the 



