YCHTHYOLOGY. 21 



Smelling, again, appears to be even farther developed than what is generally sup- 

 posed. The nostrils, in general, appear externally like a double hole or opening, and 

 the branches of the nerve are ramified on a sort of cushion at the bottom or upon the 

 side. In a few, they are like prolonged tubes, as among the eels, where the multi- 

 plicity of nervous filaments is very great ; and in one fish they are remarkable as being 

 placed on a sort of stalk like a mushroom, in which the openings are placed with the 

 nervous distribution. Seeing, then, a certain extent of development, we cannot doubt 

 that impressions of smell are conveyed. In proof, various perfumes are successfully 

 used by anglers to attract the fishes. 



But Cuvier hints at this sense being even of service for a purpose of more delicacy 

 that of distinguishing the difference between waters of different streams or currents ; 

 and it is probable, that, by the use of these organs, many of our migratory fresh water 

 species are enabled again to discover and return to the rivers they had previously 

 frequented. 



Such seems to be the most common distribution of the three most prevalent senses. 

 Various, however, are the modifications of their application, corresponding with the 

 manners and necessities of the individuals. 



The greater proportion of fishes are carnivorous, and find an abundant and varied food 

 in the immense profusion of moluscous animals, as well as in the smaller species of 

 their own orders, for among them may be said to exist a constant system of attack and 

 defence a general war, the stronger against the weaker. A few only subsist on vege- 

 bles, and graze the sea-weed, their pasture. The teeth, the only organs almost of pre- 

 hension, are therefore varied in innumerable forms, but are chiefly adapted either for 

 tearing or bruising. In the cartilaginous fish, we find these forms strongly developed ; 

 those of the sharks will exhibit an example of the first, of the most formidable kind, of 

 great size and strength, smooth and piercing, or sharp, but serrated. Those of the rays 

 or skates of the second, fitted for bruising, where the food is in a great part shell-fish, 

 and where the teeth are arranged as a dense pavement. In others, again, the teeth, 

 various in size and strength, are placed in the jaws, vomer, tongue, arches of the 

 bronchi, and in the throat. The latter arrangement is one of the most singular, and 

 bears the title among French ychthyologists of " dents en velour," from their exhibiting 

 the appearance, to the naked eye, of the pile of coarse velvet. These act by the 

 compression of the lower pharyngeal muscles, and an example will be found in the 

 genus Cyprinus, to which belong the greater part of those fishes which, by English 

 anglers, are denominated " leather mouths." The food being seized, is almost imme- 

 diately swallowed ; and such is its voracity, that substances entirely foreign are often 

 taken in, as may almost always be seen on examining the stomach of a cod, which 

 sometimes presents a most heterogeneous mass, little fitted for nutrition. 



Although the teeth and jaws, with pursuit, are the principal accessaries for securing 

 prey, various fishes, deprived of swiftness, entice their prey by stratagem. Such are 

 all the Siluri, with long filamentous appendages to the lips, which, in some, are said to 

 possess the property of stinging. Others, again, lurk in concealment, and dart out 

 upon the casual passers by. The Rostrated Cheetodon employs a most singular property 

 of propelling a drop of water with unerring aim and considerable force at insects 

 which have settled on aquatic plants, seizing them on their fall into the water. But of 

 all the properties with which these singular creatures are endowed, either for attack or 

 defence, that of the benumbing and electric stroke of the Torpedo and Gymnotus is the 

 most remarkable. Experiments have tended to confirm its connection with the galvanic 



