The Salmon and Trout 



jaws prolonged and the front teeth enlarged, the lower jaw being 

 hooked upward and the upper jaw emarginate or perforate; these 

 peculiarities most marked in the larger and migratory species. 



The species of this genus are of moderate or large size, black- 

 spotted, and abounding in the colder creeks, rivers and lakes of 

 North America, Europe, and Asia; no purely freshwater species 

 occurring in America east of the Great Plains; 5 Atlantic Coast 

 species, one marine and anadromous. 



The non-migratory species (sub-genus Tnttta) occur in both 

 continents, are extremely closely related and difficult to distinguish, 

 if, indeed, all be not necessarily regarded as forms of a single 

 exceedingly unstable, and variable species. The excessive varia- 

 tions in colour and form have given rise to a host of nominal 

 species. 



European writers have described numerous hybrids among 

 the various species of Salmo, real or nominal, found in their 

 waters. We have thus far failed to find the slightest evidence of 

 any hybridism among American Salmonidm in a state of nature. 

 Puzzling aberrant or intermediate individuals certainly occur, but 

 such are not necessarily "hybrids." 



The following interesting and pertinent observations on the 

 species of trout are taken, with some modification, from Dr. 

 Giinther: 



There is no other group of fishes which offers so many diffi- 

 culties to the ichthyologist, with regard to the distinction of the 

 species, as well as to certain points in their life history, as this 

 genus. The almost infinite variations of these fishes are dependent 

 on age, sex and sexual development, food, and the properties of 

 the water. The colouration is, first of all, subject to great varia- 

 tion, and consequently this character but rarely assists in distin- 

 guishing a species, there being not one which would show in all 

 stages the same kind of colouration. The young in all the species 

 of the genus are barred, and this is so constantly the case that it 

 may be used as a family character. When the young have passed 

 this "parr" stage the colour becomes much diversified. The 

 males, especially during and immediately after the spawning sea- 

 son, are more intensely coloured and variegated than the females, 

 immature individuals retaining a brighter silvery colour and being 

 more like the female. Food appears to have less influence on the 



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