68 The Natural History of the Salmon. 



spots. As far as can be judged by studying the 

 various works on the Salmonidae, Giinther, Chol- 

 mondeley Pennell, Day, and others, these may be 

 divided into three classes. 



First. Those with single series of vomerine teeth, 

 mostly disappearing at mature age, as the salmon 

 {Salmo salar), the sea trout {Sahno triittd), and, if 

 the bull trout {Salmo eriox) is a distinct species, it 

 may be put into this class.^ The teeth of these are 

 gradually lost, but for some time from one to four 

 remain. In the large salmon, from the examination 

 of a great number, I have generally found the teeth 

 on the vomer are absent or reduced to one. These 

 species are all migratory, and are all found in Great 

 Britain ; but the same distinctive difference is to be 

 found in all foreign migratory salmonoids, as the 

 so-called Sahno argentens from the Atlantic rivers 

 of France, Salmo mistops from Norway, Salnio vener- 

 fiensis of Sweden, etc. 



Second. Those with single series of vomerine 

 teeth, persistent during life, viz., — Sahno Oiradensis, 

 the Orkney trout. Sahno fei'ox, the Great Lake 



^ Some suppose the bull trout is a hybrid, but if so, it cer- 

 tainly propagates its species, or from whence come the enor- 

 mous number which frequent the Tweed and its tributaries? 

 Dr. Giinther makes Sdlmo eriox and Salmo Cambricus the 

 same, but the Sewin and the Sea trout rarely attain a very 

 large size. The bull trout, on the contrary, often reaches 

 from 20 to 30 pounds. 



