Trout V. Smolt. 103 



unintentionally retained smolts, until practice and the 

 application of the several tests have enabled us to deter- 

 mine the species at a glance. 



A difficulty we have to contend with in the identifi- 

 cation of Salmonidse lies in the fact that those of a kind 

 vary one from another, and the task becomes more arduous 

 when it so happens that the variations in two specimens of 

 different species tend in the direction of each other's normal 

 characteristics. For instance, if a trout be light in colour, 

 and the finger-marks on the sides of the smolt happen to 

 be very indistinct, the result is an unusual resemblance 

 between the two. 



It should be understood that, although the following 

 characteristics are generally correct, instances are of common 

 occurrence in which fish do not clearly illustrate some one 

 or more of them — in which case the further tests must be 

 applied until the question is decided. 



To the trained eye a considerable difference exists 

 between the shape and outline of trout and smolt, for 

 while that of the latter is elegance itself, the trout is of 

 more clumsy build, particularly as regards the head, 

 jaw, and gill-cover, and his outline is more or less 

 lumpy. 



When frequenting streams running fast over gravelly 

 beds, the trout may be as bright in colour as the smolt, 

 especially early in the season, just prior to the smolt 



