56 SCIENCE SKETCHES. 
As the season advances, the difference between 
the males and females becomes more and more 
marked, and keeps pace with the development of 
the milt, as is shown by dissection. The males 
have (1) the premaxillaries and the tip of the lower 
jaw more and more prolonged, both of the jaws 
becoming finally 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 Oncorhynchus 
gorbuscha, but is found in all. (5) The scales dis- 
appear, 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, ac- 
cording to the species. The blue-back turns rosy 
red, the dog salmon a dull blotchy red, and the 
quinnat generally blackish. The distorted males 
are 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 or- 
gans. 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 distorted. 
