THE SALMON FAMILY. 69 



which are persistent throughout life, in a long 

 double series on the shaft of the vomer. About 

 seven species are laboriously distinguished by Dr. 

 Giinther, in the waters of western Europe. Most 

 of these are regarded by Dr. Day as varieties of 

 Salmo fario. The latter species, the common 

 river-trout or lake-trout of Europe, is found 

 throughout northern and central Europe, wher- 

 ever suitable waters occur. It is abundant, gamy, 

 takes the hook readily, and is excellent as food. 

 It is more hardy than the different species of charr, 

 although from an aesthetic point of view it must 

 be regarded as inferior to all of the Salvelini. 

 The largest river-trout recorded by Dr. Day 

 weighed twenty-one pounds. Such large indi- 

 viduals are usually found in lakes in the north, 

 well stocked with smaller fishes on which trout 

 may feed. Farther south, where the surroundings 

 are less favorable to trout-life, they become mature 

 at a length of less than a foot, and a weight of a 

 few ounces. These excessive variations in the 

 size of individuals have received too little notice 

 from students of Salmonidte, Similar variations 

 occur in all the non-migratory species of Salmo 

 and of Salvelinus. Numerous river-trout have 

 been recorded from northern Asia, but as yet 

 nothing can be definitely stated as to the number 

 of species actually existing. 



In North America, only the region west of the 

 Mississippi Valley, and the valley of Mackenzie 

 River, have species of black-spotted trout. If we 

 are to follow the usage of the names " salmon " 

 and " trout," which prevails in England, we should 



