THE SALMON FA MIL V. 47 



The writer and his associate, Professor Charles H. 

 Gilbert, have had, under the auspices of the United 

 States Fish Commission, better opportunities to 

 study the different species of Oncorhynchus than 

 have fallen to the lot of any other ichthyologists. 

 The following discussion of the different species 

 is condensed from our report to the United States 

 Census Bureau, portions of which were published 

 in the ** American Naturahst" for March, 188 1. En- 

 tirely similar conclusions have been independently 

 reached by Dr. Tarleton H. Bean, who visited Alaska 

 in 1880, and whose means of studying the species 

 have been scarcely less extensive. 



There are five species of salmon {Oncorhynchus) 

 in the waters of the North Pacific. We have at 

 present no evidence of the existence of any more 

 on either the American or the Asiatic side. These 

 species maybe called: (i) the Quinnat, or King 

 Salmon, (2) the Blue-back Salmon, or Red-fish, 

 (3) the Silver Salmon, (4) the Dog Salmon, and 

 (5) the Humpback Salmon; or (i) Oncorhynchus 

 tschawyischa, (2) O ncorhynchics nerka, (3) Oncorhyn- 

 chics kisutch, (4) Oncorhynchus keta, and (5) Onco- 

 rhynchus gorbuscha. All these species are now 

 known to occur in the waters of Kamtschatka as 

 well as in those of Alaska and Oregon. These 

 species, in all their varied conditions, may usually 

 be distinguished by the characters given below. 

 Other differences of form, color, and appearance 

 are absolutely valueless for distinction, unless 

 specimens of the same age, sex, and condition 

 are compared. 



The Quinnat Salmon {Oncorhynchtis tschawyischa) 



