24 AMERICAN GAME FISHES. 



chief. Some of the Arctic rivers, hke the Mackenzie, are 

 barren of Salmon, as is true also of some Atlantic coast rivers. 

 Doubtless there are abundant physical reasons to account for 

 this as well as for the big break in the range of the Salmon 

 made by the interposition of the great Hudson Bay; and when 

 these are ascertained, scientists may be able to discover why 

 the fish to the eastward of the Bay are of one species (Sa/ar), 

 and those to the westward of another {CJionicJid). 



In the physiology of the animal kingdom, naturalists have 

 discovered that the quality of adaptation to environment 

 plays an important part in bringing about and establishing 

 those variations from original forms, which are called spe- 

 cies. Constancy of a primitive type depends upon the con- 

 stancy of external conditions. Now, it was long ago discov- 

 ered that not only can many species of fish gradually accom- 

 modate themselves to either salt or fresh water, but some 

 seem quite indifferent to rapid changes from one to the other. 

 On this basis scientists are readily able to account for that 

 fresh-water variety of Atlantic Salmon known as 5. Salar 

 var. Scbago, which in all respects, except the habit of 

 anadromy, it so nearly resembles. So closely, indeed, are 

 the generic traits maintained, that even the food materials of 

 both the salt and fresh water species are analogous, one sub- 

 sisting on caplins, and the other on its related species, the 

 smelts, while the geographical ranges of the two are co-ex- 

 tensive and conterminous. Both the Atlantic and Pacific 

 varieties are represented by fresh-water analogues: for the 

 Land-locked Salmon are not only distributed throughout Que- 

 bec, Ontario, and the maritime provinces of Canada, as well 

 as Maine, but they occur in the lakes of British Columbia 

 and Idaho, and in tributary lakes of Lake Superior, where they 

 "are called Red Trout by the natives, and grow to the size of 

 forty pounds, and are not to be confounded with the com- 

 mon Lake Trout [S. Namaycusli), whose flesh is white. *^ 

 (L. H. Smith, of Strathroy, Canada, in Loiidoti Fu/d.) 



