I PISCATORIAL REMINISCENCES 



especially if it be fresh water, it is necessary for 

 the animal to give its body some degree of motion, 

 in order to prevent its sinking. Dr. Roget. 



FORM OF FISHES, 



We cannot fail to perceive, on the most cur- 

 sory glance, the beautiful adaptation of the form 

 and structure of all these animals to the properties 

 of the element in which they are destined to 

 reside. In order that the fish might glide through 

 the fluid without the least resistance, all its vital 

 organs have been collected into a small compass, 

 and the body has been reduced into a compact 

 oval, compressed laterally, and tapering to a thin 

 edge both before and behind, for the purpose of 

 readily clearing the water as the fish darts for- 

 ward, and also obviating the retardation that 

 might arise from the reflux of the water collected 

 behind. Dr. Roget. 



The entire structure of fish is evidently adapted 

 to swimming, as that of birds to flight ; suspended 

 in a fluid nearly as heavy as themselves, the 

 former have no need of wings to sustain them in 

 it. A great number of species have (immediately 

 under the spine) an air-vessel, which, by compres- 

 sion or dilatation, changes the specific gravity of 

 the fish, and assists it in arising or descending in 

 the water. Progression is executed by the motion 

 of the tail, right and left. Cuvier. 



