572 MR. J. A. MILNE ON THE 



<37. Pacific Saluion : An Attempt to evolve somethino- o£ 

 their History from an Examination of their Scales. 

 By John Adam Milne, of Ardmiddle, Turriff, 

 Aberdeenshire *. 



[Received April 9, 1913 ; Read May 6, 1913]. 

 (Text-figm-es 95-118.) 



Salmonid.e : Structure, Development, Ethology. 



The above title indicates what is pei'haps a somewhat hold 

 venture on the part of one who lives on the east side of the 

 Atlantic, and who has only once seen a freshly killed Pacific 

 salmon during a short visit to Vancouver in 1893. The 

 reasons for my undertaking it are that, so far as I have been 

 able to ascertain, the study of salmon scales has not yet made 

 much progress in America, that undoubtedly much may be dis- 

 covered from them, and that even such inadequate observations 

 as I have been able to make may afford most valuable hints to 

 others better able to procure materials for the study of the habits 

 of the so-called salmon of the Pacific. I say so-called, because with 

 one exception, Salmo gairdneri, the Steelhead Trout, the Pacific 

 salmon do not belong to the same division of the genus Salmo as ■ 

 the salmon of the Atlantic Ocean. Excepting the Steelhead, 

 they belong to the subgenus Oucorhynclvus, while our salmon and 

 trout belong to the subgenus Salmo. 



I shall have to notice five species of Oncorhynchus which 

 breed in the rivers and streams of Western North America. 

 They are 0. quinnat, or 0. tscJiaioytscha, the Quinnat, King, Tyee, 

 or Spring Salmon ; 0. nerha, generally known as the Sockeye, 

 from the sunken appearance of the eyes, and also called the 

 Blueback and the Red Salmon ; 0. hisutch, the Cohoe, Silver, 

 White, or Fall Salmon ; 0. gorhuscha, the Humpback, so called 

 from a peculiar hump which appears on the backs of the males 

 at spawning time ; and 0. keta, the Dog or Chum Salmon. A 

 sixth species, 0. masu, is found on the Siberian coast and in 

 Japan, but I shall not deal with it here, as I intend to confine 

 my remarks to the salmon of the Pacific coast of North America. 

 It is there that full knowledge of the habits of the Pacific salmon 

 is of the gx'eatest importance on account of the magnitude of the 

 canning industr}^, to which every one of the native species 

 now conti'ibutes its quota. 



When the canning industry was first started in the West, the 

 <5uinnat only was cared for, but soon the Sockeye was recognized 

 as a fish of much greater importance. The value of the remaining 

 species has only recently been appreciated. 



It is generally believed that none of the fish of the genus Onco- 

 rhynchus that go to the rivers ever return and that all die after 



* Communicated by the Seceetaex. 



