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THE SALMON TRIBE. 



This family forms the genus Salmo of Linnaeus, and is 

 characterized by the insertion of the mystache, or true maxillary 

 bones, on each side of the snout or intermaxillaries, by a hinge; 

 by the armature of the mouth, where the jaws and border of 

 the mystache are furnished with teeth, as are generally the roof 

 of the mouth, with also two rows along the sides of the tongue; 

 and also by the presence of two fins on the back, of which the 

 hindmost is small and destitute of rays. In this last particular 

 the fishes of this family stand alone among the fishes of Europe ; 

 but there is something like it in some Indian species; as of the 

 genus Pimelodus, which in this respect forms a link between 

 the genus Salmo and the apparently very different genus Silurus. 

 The armature of the mouth is less a mark of the extensive 

 family of Salmons and Trouts, as there are some aberrant sub- 

 genera which have teeth less visibly in the jaws, or are altogether 

 without them ; but all are abdominal fishes, and within the body 

 the air-bladder communicates with the gullet by means of a 

 tube, the opening of which is clearly visible. As no visible 

 nerve is seen distributed to the rayless fin on the back, this 

 part seems to be only possessed of common and not specific 

 sensation. 



By Cuvier this extensive family is divided into several 

 genera, of which on many accounts the first stands conspicuous. 



