SALMONOIDEjE. 137 



SALMONOIDEiE. 



The fish of this family were collected by Linnaeus into a single great genus, which 

 is concisely characterised by a scaly body ; a first dorsal having articulated rays ; 

 and a second small one, not sustained by rays, but formed merely of a fold of the 

 skin enclosing fat, and hence named the adipose fin. The Salmonoidece have 

 numerous caeca and an air-bladder ; they almost all ascend rivers, their habits are 

 voracious, and most of them are highly esteemed as articles of food. The sur- 

 prising variety which exists in their dentition, and in the structure of their jaws, 

 furnishes characters for the numerous sub-genera into which Cuvier has divided 

 this extensive genus : but owing to the absence of obvious peculiarities by which we 

 may distinguish one species from another of the same group in this family, and the 

 difficulty of collecting specimens from various countries for comparison, inextri- 

 cable confusion has crept into the synonymy. The loss which science has sus- 

 tained in the death of Cuvier has deferred the rectification of this, which must 

 be accomplished by some ichthyologist of adequate means and talents, before a 

 precise statement can be made respecting the geographical distribution of the 

 species. 



In the Trouts, or true Salmon, constituting the first sub-genus (Salmo, Cuvier), 

 the labials form a large portion of the border of the upper jaw, and there is a row 

 of pointed teeth on these bones, the intermaxillaries, lower jaw, and palate-bones, 

 and two rows on the vomer, tongue, and pharyngeals, so that the dentition is more 

 complete than in any other tribe of fish. In the old males the point of the lower 

 jaw is incurvated, and lodges in a cavity formed in the forepart of the roof of the 

 mouth, anterior to a transverse membrane. The shape of the trouts is known to 

 every one. Their ventrals are opposed to the middle of the dorsal, and the adipose 

 is over the anal. They have about ten gill-rays. Their long, narrow stomach 

 doubles upon itself, and the pyloric ceeca are very numerous ; the air-bladder 

 reaches from one end of the abdomen to the other, and communicates with the 

 upper part of the oesophagus. The trouts have almost always spotted bodies, and 

 they are generally excellent food. They ascend rivers to spawn and surmount 

 cascades, thus attaining the rivulets and small lakes of the highest mountains. 

 Such is the compendious character of the sub-genus contained in the Regne Animal, 

 to which we may add, that the group is an exceedingly natural one, so much so, 



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