THE SALMON 53 



(6) P. D. Malloch, Life-History and Habits of 



the Salmon, Sea Trout^ and other Fresh- 

 water Fish. London, 1910. 



(7) J. A. Hutton, Salmon Scale Examination 



and its Practical Utility. London, 1910. 



The Salmon of the North Pacific belong to five 

 species, which are placed in a distinct genus (Onco- 

 rhynchus) ; they may be mentioned here because they 

 form the basis of the tinning industry, and because 

 their habits are those of our Salmon in an exaggerated 

 form ; they run up in enormous numbers, the spawning 

 fish change greatly in colour and appearance, the 

 jaws in the males becoming excessively long and 

 hooked at the tip, and the front teeth much enlarged ; 

 the development of the sexual organs seems to be 

 at the expense of all the other tissues, which are so 

 degenerated that when the act of spawning is 

 completed every individual dies, none being in a 

 condition to feed or get back to the sea. An un- 

 successful attempt has been made to introduce one 

 of these species, the Quinnat, into European waters. 



