266 TEETH, HEARING, AND BRAIN OF FISHES. 



offish are only representations of that beautiful and ani- 

 mated organ which is found in the superior class of animals." 



" The teeth of fishes," says Professor Owen, '* whether we 

 study them in regard to their number, form, substance, 

 structure, situation, or mode of attachment, ofier a greater 

 and more striking series of varieties than do those of any 

 other class of animals. In number they range from zero to 

 countless quantities. In the sharks and rays the teeth are 

 supported by the upper or lower jaws, as in most quadrupeds ; 

 but many other fishes have teeth growing from the roof of 

 the mouth, from the surface of the tongue, from the bony 

 hoop or arches supporting the gills, and some have them 

 developed from the bone of the nose and the base of the 

 skull." In all fishes the teeth are shed and renewed not 

 once only as in mammals, but frequently during the whole 

 course of their lives. 



Fishes have but small occasion for the sense of hearing^ 

 being condemned to reside in the empire of silence, where 

 all around is mute. In most fishes the auditory parts are 

 buried in the skull, and send no process to the surface. 



Singular stories, however, are told of fishes being sensible 

 to the sound of music. Ancient writers — ^lian and Aris- 

 totle — mention some fishes, and particularly skates, who are 

 attracted in this manner. Two men embark in a boat, one 

 with a musical instrument and the other with a net, and by 

 this music the fishes become so entranced as to be taken 

 easily. A somewhat similar mode is said to be practised by 

 the boatmen of the Danube, who use bells for the purpose. 

 Carp have been known to distinguish the sound of a bell, 

 and the voice of their keeper when called to be fed. 



The hrain of fishes is remarkably small in proportion to 

 the size of the animal, the quantity of nerves arising out of 

 it, and the size of the cavity which contains it. The space 

 thus left vacant is often filled with oil or fat. 



Some fishes are not altogether indifferent to the fate of 



