HOW THE TROUT CAME TO CALIFORNIA. 271 
spread itself widely in the streams of the green 
and moist region west of the Cascade Range and 
through the arid lava-strewn wildernesses which lie 
to the east. Each stream received its quota of 
trout ; but as the way was open up and down the 
stream, the species remained essentially as it was 
in Alaska. Isolation or separation from the main 
body in some way is a prime factor in the perma- 
nence of new forms. In Waha Lake! in Wash- 
ington, a glacial lake which has now no outlet, the 
trout became entirely cut off from the parent stock, 
and a local race with shorter head and the black 
spots gathered on the tail was formed by the 
separation. In the central portion of this region, 
east of the Cascade Range, we find still the an- 
cestral forms of the nascent species which have 
sprung from Salmo mykiss. In this region the 
scales are small, but the cut-throat mark is often 
wanting, and there are still living forms that seem 
to mark a perfect transition? from Salmo mykiss 
to Salmo gairduert. In the region where these 
forms are found, the true my&zss is nearly or quite 
wanting. 
The trout thus came to the fountain-head of 
the Columbia, and its great tributaries the Snake, 
the Salmon, and Clark’s Fork. In this Upper 
Snake River it has become separated, since the 
last lava flows, from the parent form, and it is 
1 The Waha Lake Trout has received the name of Salmo 
mykiss bouvieri, This name was given by Major Charles Bendire, 
its discoverer, one good soldier naming it for another. 
2 These transitional forms, abundant about Walla Walla and 
in the Des Chfites River, are known as Salmo mykiss gibbsit, named 
for the discoverer, George Gibbs, once governor of Washington. 
