The Identification of Salmon and Trout. 147 



of the streams and rivers in which the speci- 

 mens are found, that the ichthyologist some- 

 times finds the determination of the identity 

 of individual specimens of the genus a most 

 difficult problem to solve. The difficulties 

 are greater also from the development of the 

 sexual characters materially changing the 

 appearance of the fish at certain seasons, 

 the colour differing most markedly at the 

 breeding season, and in the males the cartil- 

 aginous protuberance, which is then formed 

 on the under jaw, completely alters their 

 appearance. Added to this is the ascertained 

 fact that many, if not all, of the species are 

 capable of hybridization, and the hybrids have 

 in some cases been found to be capable of 

 propagating their kind, and of again crossing 

 with the pure race. Hence it is not im- 

 probable that there are intermediate forms, 

 connecting — in many cases — the different 

 genera, and rendering identification difficult, 

 if not impossible. The crosses between the 

 salmon and the trout are of rare occurrence in 

 their natural state, but by artificial impregna- 

 tion this has often been effected. I have 

 failed, however, to find any record of hybrids 



