86 REPORT OF STATE BOARD OF FISH COMMISSIONERS. 



The black-spotted trout, forming the subgenus Sahn-, differ from 

 Salmo salar and Salmo trutta in the greater development of the vom- 

 erine teeth, which are persistent throughout life, in a long double series 

 on the shaft of the vomer. About seven species are laboriously distin- 

 guished by Dr. Guenther 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 Sal- 

 velini. 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. 

 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 Salmonida' . Similar varieties 

 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, the 

 streams of southeastern Alaska, and the valley of the Mackenzie River 

 have species of black-spotted trout. There are few of these north of 

 Sitka in Alaska, although black-spotted trout are occasionally taken on 

 Kadiak and al^out Bristol Bay, and none east of the Rocky Mountain 

 region. If we are to follow the usage of the names " salmon " and 

 " trout " which prevails in England, we should say that, in America, it 

 is only these western regions which have any trout at all. Of the num- 

 ber of species (about twenty-five in all) which have been indicated by 

 authors, certainly not more than about eight to ten can possibly be 

 regarded as distinct species. The other names are either useless syno- 

 nyms, or else they have been applied to local varieties which pass by 

 degrees into the ordinary types. 



In the western part of America are found more than a score of trout 

 of the genus Salmo, all closely related and difficult to distinguish- 

 There are representatives in the headwaters of the Rio Grande, Arkan- 

 sas, South Platte, Missouri, and Colorado rivers; also in the Great Salt 

 Lake basin, throughout the Columbia basin, and in all suitable waters 

 from southern California and Chihuahua to Sitka, and even to Bristol 

 Bay, similar forms again appearing in Kamchatka and Japan. 



Among the various more or less tangible species tliat may be recog- 

 nized, three distinct series app ^. These have been termed the cut- 



