76 SCIENCE SKETCHES. 
are not migratory, or only to a limited extent. In 
northern regions they descend to the sea, where 
they grow much more rapidly, and assume a nearly 
uniform silvery-gray color. The different species 
are found in all suitable waters throughout the 
northern parts of both continents, except in the 
Rocky Mountains and Great Basin, where only 
the black-spotted trout occur. The number of 
species of charr is very uncertain, as, both in 
America and Europe, trivial variations and indi- 
vidual peculiarities have been raised to the rank 
of species. More types, however, seem to be rep- 
resented in America than in Europe. 
The only really well-authenticated species of 
charr in European waters is the Red Charr, Salb- 
ling, or Ombre Chevalier (Sa/velinus alpinus). 
This species is found in cold clear streams in 
Switzerland, Germany, and throughout Scandina- 
via and the British Islands. Compared with the 
American charr or brook-trout, it is a slenderer 
fish, with smaller mouth, longer fins, and smaller 
red spots, which are confined to the sides of the 
body. It isa “gregarious and deep-swimming fish, 
shy of taking the bait and feeding largely at night- 
time. It appears to require very pure and mostly 
deep water for its residence.” It is less tenacious 
of life than the trout. It reaches a weight of from 
one to five pounds, probably rarely exceeding the 
latter in size. The various charr described from 
Siberia are far too little known to be enumerated 
here. 
Of the American charr the one most resembling 
the European species is the Rangeley Lake Trout 
