BULL TROUT, Saline S. griseus, a fish nearly allied to the salmon, and like it, migratory in its habits, ascending rivers, in which it deposits its spawn, but living chiefly in the 'sea. It occurs in many of the rivers of Britain, and is not unfrequently taken in the Tweed and its tributaries. It is frequently called the GRAY TROUT, sometimes simply the GRAY, and is the SEWEN of the Welsh rivers. It sometimes attains the weight of 20 lbs., although it is more commonly under 15 lbs. weight. It is less elegant in form than the salmon; the head and nape of the neck are thicker in proportion; and the tail, beyond the adipose fin, is more bulky and muscular; the tail fin is square at the end in young fish (in some places called whitlings), and in older ones, becomes con vex by the elongation of the central rays, whence the name roundtail sometimes given this species. The scales are rather smaller than those of a salmon of equal size, and the color is less bright; the males in the spawning season being reddish brown, the females blackish gray; at other times the general color is like that of the salmon trout.
The B. T. agrees with the salmon iu a few teeth on the most anterior part of the tomer (the bone which runs down 'the center of the palate); while the salmon trout, the common trout, and the great lake-trout, have a long line of teeth there: the teeth are larger and stronger than those of the salmon; there are differences also in the form of the gill-covers. To anglers the B. T. is next to the salmon as a prize, and by many is mistaken for it. The flesh is paler in color, coarser, with much less flavor, and is much less esteemed.—The name B. T. has been also given to the Hucllo (salmo huelw), or salmon of the Danube, which sometimes attains the size of 30, or it is said, even of 60 lbs.