20 THE NATURALIST. 



hearing, and smelling, all very acute. Those of taste and touch are to all appearance 

 in subordinate development, nor with the powerful exercise of the others are they con- 

 ducive, or necessary to the existence of the individual. There is a general sense of 

 feeling by contact with any body over the surface of the animal ; but unless in those 

 species which are furnished with long filamentous appendages to the head, there is no 

 organ by which this property is regularly exercised. In those fish, when lying at the 

 bottom in disturbed water, the filaments are extended, and may serve to make them 

 aware of the approach of an enemy ; and among others, (in the Siluri,) where they are 

 of great length, and are thrown out and moved, to attract attention ; from their sensi- 

 bility of touch, while the fish remains in concealment, they may warn the lurker that 

 his prey approaches, and enable him to prepare for its seizure. 



The sense of taste seems even developed in a less degree, the organ in which it is 

 generally implanted being used as an accessory to prehension, and often armed with 

 very strong teeth. Swallowing, also, almost immediately follows the seizure; the 

 prey, gorged entire, and without mastication in the mouth, is rapidly dissolved and 

 digested in the stomach. 



The important function of vision is imparted to fishes to a greater extent, and if, per- 

 haps, the range of seeing be not great, when within its bounds it is apparently acute 

 and distinct ; and as among the higher vertebrata we have some which are nocturnal in 

 their habits, as well as those which seek their prey by day, so we find among fishes a 

 difference of form in the large eyes of many species which constantly remain at a 

 depth of many hundred fathoms below the surface, and where it has been proved that 

 the influence of light could not extend. In some, again, the eyes are remarkable for 

 their minuteness, and to several species the specific name Ccsca, or blind, has been ap- 

 plied. These, like the mole in her dark galleries, live in the banks of muddy rivers, 

 and are no doubt furnished with some more exquisite sense to supply their wants, and 

 minister to their sustenance. In the Gastrobranchus, a fish remarkable in all its struc- 

 ture, no trace whatever of eyes has yet been discovered. 



Water, the medium through which fishes hear, has been proved to be a better con- 

 ductor of sound than air ; and, from a variety of experiments, sounds produced under 

 water have a loud and clear impression on the human ear, placed in the same situa- 

 tion. In fishes there is no external ear, except in a few where a very small cavity is 

 discernible. They want the tympanum, the small bones, and the eustachian tubes ; 

 but the semi-circular canals are often largely developed. In the osseous fishes, the 

 whole of the labyrinth of the ear projects into the cavity of the cranium. The laby- 

 rinth is filled with a transparent liquid, distending the vestibule and sack, which con- 

 tain small and peculiar bony substances, two or three in number, which float in the 

 liquid, and would apparently convey the sense of any concussion to the nervous linings 

 of the edges, and upon the principal plexus of the auditory nerve, which is ramified in 

 the greatest proportion on the walls of the sack, which generally contains the largest 

 of these hard osseous bodies. 



The structure of the ears in fishes is certainly less perfect and less complicated 

 than in the higher mammalia and birds ; and Cuvier is of opinion, that though they 

 hear sounds distinctly, or as concussions, yet they are unable to distinguish any of the 

 finer tones or variations. That they are sensible of the impulses of sound has often 

 been proved, and fish are known to approach for food at the whistle of their keeper. 

 The Romans were even said to have taught each to approach upon being called by a 

 particular name. 



