Salmonidas 



79 



strongly and often extravagantly hooked, so that either they 

 shut by the side of each other like shears, or else the mouth 

 cannot be closed. (2) The front teeth become very long and 

 canine-like, their growth proceeding very rapidly, until they 

 are often half an inch long. (3) The teeth on the vomer and 

 tongue often disappear. (4) The body grows more compressed 

 and deeper at the shoulders, so that a very distinct hump is 

 formed; this is more developed in the humpback salmon, but 

 is found in all. (5) The scales disappear, especially on the 

 back, by the growth of spongy skin. (6) The color changes 

 from silvery to various shades of black and red, or blotchy, 

 according to the species. The blue-back turns rosy-red, the 

 head bright olive ; the dog-salmon a dull red with blackish bars, 

 and the quinnat generally blackish. The distorted males are 



FIG. 60. Quinnat Salmon, Oncorhynchus tschaivytscha (Walbaum). 

 Monterey Bay. (Photograph by C. Rutter.) 



commonly considered worthless, rejected by the canners and 

 salmon-salters, but preserved by the Indians. These changes 

 are due solely to influences connected with the growth of the 

 reproductive organs. They are not in any way due to the 

 action of fresh water. They take place at about the same time 

 in the adult males of all species, whether in the ocean or in the 

 rivers. At the time of the spring runs all are symmetrical. 

 In the fall all males, of whatever species, are more or less dis- 

 torted. Among the dog-salmon, which run only in the fall, 

 the males are hook-jawed and red-blotched when they first 

 enter the Strait of Fuca from the outside. The humpback, 

 taken in salt water about Seattle, have the same peculiarities. 

 The male is slab-sided, hook-billed, and distorted, and is re- 



