SALMON. 9 
confusion still exists. This, however, is not for 
want of attention to the subject by naturalists, 
The discrimination between species and varieties 
is often a difficult matter, and in this connection, 
no rule which has been laid down has held good 
for any length of time. This is owing to the 
fact that fresh-water fishes adapt themselves to 
local circumstances more effectually and more 
rapidly than any other class of creatures. In 
fact, in the family under notice, it is hardly 
known what are salmon and what are trout; 
and the only satisfactory division is that of 
migratory and non-migratory species. These 
include the salmon, brown brook-trout, bull-trout, 
salmon-trout, gillaroo, sewin, short-headed salmon, 
great lake-trout, Loch Leven trout, a number of 
others, and some char. Many of these are no- 
thing more than varieties with local peculiarities, 
probably produced by different conditions of 
food and water in their particular haunts. The 
inclination of naturalists has been to evolve 
species from mere varieties by a process of 
hair-splitting ; but in the future, and as the laws 
which govern evolution become better under- 
stood, the tendency will probably be the other way. 
The salmon- or sea-trout, is, as its name 
implies, one of the migratory species. It is 
common in most salmon rivers, and is widely 
