FISHES OF PENNSYLVANIA. 77 
Uses and Capture.—The value of the salmon as a food and game fish 
is so well known as to require no description here. Those that find 
their way into market are usually caught in pound-nets, gill-nets or 
seines, and the bulk of them are taken at or near the mouths of the 
streams which they are about to enter for the purpose of spawning. 
Many are captured in the upper reaches of streams by the spear. 
91. Salmo irideus Grszons. 
The Rainbow Trout. (Figure 5.) 
The rainbow trout has a short and deep body, its greatest depth equaling two- 
sevenths of the total length withoutcaudal. Theleast depth of caudal peduncle equals 
one-balf length of head. The head is short and deep ; its length containedsabout four 
and two-thirds times in the total length without caudal. The snout is short, not much 
exceeding the eye in length and about one-fourth length of head. The length of the 
eye is contained four and two-thirds times in that of the head. The maxilla does 
not quite reach to the end of the eye. The origin of the dorsal is’a little nearer tip of 
snout than root of tail. The length of its base is contained seven and one-half times 
in total without caudal, and slightly exceeds its longest ray. The last ray is one-half 
length of longest. The ventral origin is under the middle of the dorsal base. The 
length of the fin equals longest dorsal ray. The ventral appendage is about as long 
as the eye. When the ventral is extended the distance of its tip from vent is one- 
third length of head. The distance of ventral origin from anal origin slightly ex- 
ceeds length of head. The length of the anal base is a little more than half length 
of head. Its longest ray equals the longest dorsal ray. Its last ray is somewhat 
less than the length of the eye. B. 11; D. 11 divided rays and 4rudiments. <A. 10 
divided rays and 3rudiments. Scales 21-135-20. he adipose fin is short, its width 
nearly equal to its length and two-thirds length of eye. 
The upper parts greenish blue, often purplish. The sides more or less silvery 
and protusely spotted with small black spots, these most numerous above lateral 
line. Head, dorsal, adipose, and caudal fins also black spotted. Sea-run specimens 
are uniform silvery without black spots. In the breeding season the broad crimson 
lateral band becomes brighter, and the sides of both sexes are iridescent purplish. 
The jaws of the male in the breeding season are not much distorted, but they are 
very much larger than in the female. 
Names.—The rainbow trout is known also as California mountain 
trout, specked trout, golden trout, and brook trout. 
Distribution.—This species ranges from California, near the Mexican 
boundary, to southern Alaska. A small specimen was taken at Sitka in 
1880 by Captain L. A. Beardslee, U.S.N. The rainbow is found chiefly 
in mountain streams west of the Sierra. Nevadas. It rarely descends 
into the lower stretches of the rivers; but occasionally does so and passes 
out to sea. In Pennsylvania the rainbow has been rather extensively 
introduced, but with such imperfect results in most cases that the Fish 
Commission has practically given up its distribution. The species re- 
produces naturally in Cumberland county and in Mill creek in Pike 
county, and doubtless in other streams. This trout has been very widely 
distributed artificially, and in numerous localities thrives greatly beyond 
all expectations. Favorite states for this species are Wisconsin, Michi- 
gan, Missouri and North Carolina. In Missouri the growth of the spe- 
cies is most remarkable, at the Neosho station of the United States Fish 
