FISHES. O 



they could not sink, and make off. It is, however, 

 a curious subject for inquiry."* 



The Diodon, as is well known, has the habit of 

 inflating its body with air, and of floating help- 

 lessly in this condition at the surface ; but in this 

 case it appears that the air is not taken into the 

 bladder, but into the huge stomach, filling the 

 cavity of the abdomen. 



" A Gold-fish, in a small fountain, in the 

 grounds of a gentleman of my acquaintance, 

 swam about for more than two months, with its 

 belly upwards. It appeared perfectly healthy 

 and lively. This change from the natural posi- 

 tion of the fish was, probably, owing to an en- 

 largement or defect in the air-bladder."-}- 



In conformity with their structure, the sphere 

 of activity of Fishes is the water. The Flying- 

 fishes, and some of the Gurnards, are able to 

 elevate themselves into the air, and to maintain 

 their position there for a few seconds ; and some 

 of the Frog-fishes and Eels can crawl upon the 

 exposed mud or sand, during the hours that inter- 

 vene between the ebb and flow of the tide ; but 

 these exceptions scarcely break the universality of 

 the law which confines Fishes to the water. 

 There is, however, considerable diversity in the 

 locality assigned to different species ; some in- 

 habit fresh-waters only, some only the sea ; 

 others are able to exist in both, either by pe- 

 riodical migration, or at pleasure. Of fresh-water 

 Fishes, some inhabit large rivers, others small 

 streams ; rapid and sluggish waters have each 

 charms for some : great inland lakes possess 

 peculiar species, and some are found only in the 

 * Jesse's Scenes of Country Life, 353. + Ibid. 356. 



