74 SCIENCE SKETCHES. 
seems to promise a ready adaptation to other 
surroundings. 
The Rio Grande Trout (Salmo mykiss spilurus) 
is a large and profusely spotted trout, found in 
the head-waters of the Rio Grande, the mountain 
streams of the great basin of Utah, and as far 
south as the northern part of Chihuahua. Its 
scales are still smaller than those of the red- 
throated trout, to which it bears much resem- 
blance, and of which it is probably simply a local 
variety. 
The genus Hucho has been framed for the Huchen 
or Rothfisch (Hucho hucho) of the Danube, —a large 
salmon, differing from the genus Sa/mo in having 
no teeth on the shaft of the vomer, and from the 
Salvelint at least in form and coloration. The 
real characters of the genus, which seems to be 
distinct from Salvelinus, have not yet been 
worked out. The Huchen is a long and slender, 
somewhat pike-like fish, with depressed snout and 
strong teeth. The color is silvery, sprinkled with 
small black dots. It reaches a size little inferior 
to that of the salmon, and it is said to be an 
excellent food-fish. Little is known of its habits. 
It has, however, the reputation of being unusually 
voracious for a salmon. 
The genus Sa/velinus comprises the finest of the 
Salmonida, from the point of view of the angler 
or the artist. In England the species are known 
as charr, in contradistinction to the black-spotted 
species of Salmo, which are called trout. The 
former name has unfortunately been lost in Amer- 
ica, where the name ‘‘trout” is given indiscrimi- 
