GEN. SALMO. THE BULL TROUT. 129 



ray in the same fin ; in old fish the terminal line of 

 the caudal fin is convex, whence this fish is some- 

 times called the RoundtaiL Scales rather smaller 

 than in the Salmon. Colour of the back dark grey 

 becoming lighter on the sides, the belly white, spots 

 generally numerous above the lateral line, and very 

 variable in shape ; dorsal and caudal fins light grey, 

 lower end of the pectorals dusky. In the spawning 

 season the male acquires a reddish brown hue, but 

 the female undergoes no material change, except 

 that her colours become darker. 



Like all the other trouts, this species exhibits an 

 immense number of varieties. Dr. Parnell describes 

 and figures eight of these occurring in the Firth of 

 Forth, but it may always be recognised by the 

 above characters. It is on^ of the migratory species, 

 ascending rivers to spawn, like the Salmon ; but it 

 is said always to precede the latter both in its 

 ascent and descent to the sea. It is rather plentiful 

 in the Tweed, having increased greatly in that river 

 of late years ; and is found not unfrequently in most 

 of the principal rivers in the United Kingdom. 



The provincial names of this trout are variously 

 applied, and the young are no doubt often con- 

 founded with those of the following species. One 

 of the varieties is known in the Firth of Forth, Sol- 

 way Firth, and elsewhere, as the Salmon-trout, 

 sometimes the young are named Whitlings by those 

 who are unacquainted with the true Whitling, 

 which is the young of S. trutta. It is the Berwick 

 Trout of the London markets. It is pretty frequent 



