48 CLASSIFICATION OF FISHES. 



to infer that the sense of taste is very slightly possessed 

 by fishes. The structure of their teeth, with few ex- 

 ceptions, shows that the food is generally swallowed in 

 an entire state, since it is so found in the stomach ; and 

 very few instances occur of fish having cutting or grind- 

 ing teeth. Besides, it has been justly observed by Mr. 

 Yarrell*. that from being obliged unceasingly to open and 

 close the jaws for the purpose of respiration, fishes can- 

 not long retain food in the mouth when shut ; the sub- 

 stance, if of small size, must be swallowed quickly. The 

 structure of the tongue tends to the same conclusion ; 

 we believe it is in all cases small, hard, and generally 

 cartilaginous, and consequently incapable of conveying 

 that exquisite taste of their food enjoyed by all the qua- 

 drupeds, and a few of the birds. f Fishes have been 

 supposed destitute of the faculty of hearing, but this 

 is disproved by many circumstances. It is known as a 

 well-authenticated fact, that the Chinese, who breed great 

 numbers of goldfish, call them together, at the time of 

 feeding, by a whistle ; and the same mode of summon- 

 ing other species by a noise, in aquatic preserves, are 

 upon record. There are, indeed, no external indications 

 of ears in any fish, excepting the rays, where there is a 

 small spiral cavity (placed before the meatus extemus, 

 and covered .by the common skin), which may be ana- 

 logous to the external ear of other animals. The internal 

 labyrinth, however, is always present, although much 

 less complicated than in the more perfect Vertebrata. 



(50.) The vitality of fishes may here be adverted to. 

 There is not sufficient evidence to show us the average 

 age of the generality of fishes; but some well authen- 

 ticated facts regarding carp, and some other domes- 

 ticated fish, tend to prove that the former have reached 

 to a century. Cartilaginous fishes, from the nature of 

 their bones, continue to grow all their lives ; and as 

 many of these, particularly the rays, habitually five in 

 the deep recesses of the ocean, and thus seldom run the 



* Yarrell's British Fishes, i. xvii. 



f Particularly the whole family of Anatidce, or ducks. 



