42 SALMONID^. 



Salmon {Salmo Salar) is this, that the caudal fin of the former 

 is convex, while that of the latter is more or less concave, or 

 forked, in proportion to the age of the individual fish. 



I shall now pass to the consideration of the gill-covers, the 

 apparatus by means of which the fish breathes ; in other words, 

 by which the oxygen is separated from the water, in which the 

 animal exists, as it enters by the mouth and passes out at the 

 aperture of the gills, conveying its influence to the blood in its 

 passage. 



This apparatus being of course of the highest degree of 

 importance to the animal, varies in form and structure accord- 

 ing to the various exigencies of the diff'erent species to which it 

 is attached; and it is therefore of great value to the observer 

 in distinguishing one family, and even one species of the same 

 family, from another. 



With regard to the family of which we are now treating (the 

 Salmonidce) , beyond all question the most important and most 

 interesting to the sportsman, as being the gamest, boldest, and 

 strongest of all the fish with which he has to do, and to the 

 epicure likewise, as affording the greatest varieties of the most 

 delicious food, the remarks I am about to make have especial 

 application. 



Of no other family known to the sportsman, are the species 

 so numerous and so difiicult of definition ; and not only the 

 truly distinct species, but the subordinate varieties, produced in 

 the same species by difference of food, of water, of bottom- 

 ground in the lakes or rivers haunted by each, and even by the 

 degrees of light or shadow which affects the localities which 

 they haunt. These varieties, often diftering by many pounds' 



