Salmonidae 95 



to be more favorable to hybridism than in others in which 

 hybrids are of comparatively rare occurrence. Hybrids be- 

 tween the salmon and other species are very scarce everywhere." 



Very similar to the European Salmo trutta is the trout of Japan 

 (Salmo perryi), the young called yamabe, the adult kawamasu, 

 or river-salmon. This species abounds everywhere in Japan, 

 the young being the common trout of the brooks, black-spotted 

 and crossed by parr-marks, the adult reaching a weight of ten 

 or twelve pounds in the larger rivers and descending to the sea. 

 In Kamchatka is another large, black-spotted, salmon-like 

 species properly to be called a salmon-trout. This is Salmo- 

 mykiss, a name very wrongly applied to the cutthroat trout of 

 the Columbia. 



The black-spotted trout, forming the subgenus Salar, differ 

 from Salmo salar and Salmo trutta in the greater develop- 

 ment of the vomerine teeth, 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 through- 

 out northern and central Europe, wherever 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 individuals are usually found in lakes in the north, well 

 stocked with smaller fishes on which trout may feed. Far- 

 ther 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 

 SalmonidcE. 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. 



The Black-spotted Trout. In North America only the re- 

 gion west of the Mississippi Valley, the streams of southeastern 



