Salmonidz 307 
same spawning grounds where they were originally hatched. 
We fail to find any evidence of this in the case of the Pacific- 
coast salmon, and we do not believe it to be true. It seems 
more probable that the young salmon hatched in any river 
mostly remain in the ocean within a radius of twenty, thirty, 
or forty miles of its mouth. These, in their movements about 
in the ocean, may come into contact with the cold waters of 
their parent rivers, or perhaps of any other river, at a consider- 
able distance from the shore. In the case of the quinnat and 
the blue-back their ‘instinct’ seems to lead them to ascend 
these fresh waters, and in a majority of cases these waters will 
be those in which the fishes in question were originally spawned. 
Later in the season the growth of the reproductive organs leads 
them to approach the shore and search for fresh waters, and 
still the chances are that they may find the original stream. 
But undoubtedly many fall salmon ascend, or try to ascend, 
streams in which no salmon was ever hatched. In little brooks 
about Puget Sound, where the water is not three inches deep, 
are often found dead or dying salmon which have entered them 
for the purpose of spawning. It is said of the Russian River 
and other California rivers that their mouths, in the time of 
low water in summer, generally become entirely closed by sand- 
bars, and that the salmon, in their eagerness to ascend them, 
frequently fling themselves entirely out of water on the beach. 
But this does not prove that the salmon are guided by a mar- 
velous geographical instinct which leads them to their parent 
river in spite of the fact that the river cannot be found. The 
waters of Russian River soak through these sand-bars, and 
the salmon instinct, we think, leads them merely to search for 
fresh waters. This matter is much in need of further investi- 
gation; at present, however, we find no reason to believe that 
the salmon enter the Rogue River simply because they were 
spawned there, or that a salmon hatched in the Clackamas 
River is more likely, on that account, to return to the Clacka- 
mas than to go up the Cowlitz or the Des Chutes.” 
Attempts have been made to settle this question by marking 
the fry. But this is a very difficult matter indeed. Almost 
the only structure which can be safely mutilated is the adipose 
fin, and this is often nipped off by sticklebacks and other med- 
