NATURAL HISTORY OF BRITISH SALMONID^. 153 



somewhat rounder or more tapering than either of its con- 

 geners, the form of the gill lids and proportions of the tail 

 being intermediate between the two. The scales are also re- 

 latively smaller. 



Indigenous in almost all salmon or bull-trout rivers, and 

 frequently abounding in streams which produce neither the 

 one nor the other, there is no fish that swims which, when in 

 the taking mood, will rise so boldly at the fly, or make a 

 pluckier or more brilliant fight. 



In the division which I have adopted between the white or 

 migratory species of trout and the yellow or non-migratory 

 species, the sea trout is the only one about which any difficulty 

 of identification is likely to arise. The difference in colour 

 between Xhe.farw and the trutta—ihe one being silver and the 

 other golden or yellow — is usually too obvious to admit of 

 doubt ; but, especially when confined for a long time in a lake 

 or loch, sometimes the sea trout gets bronzed and acquires a 

 colour not very unlike that of the common trout. If a doubt 

 as to the species should thus arise a reference to the teeth on 

 the vomer or central bone on the roof of the mouth will decide the 

 point. These teeth in the common trout — as also in the great 

 lake trout — run in two distinct rows, whilst in the sea trout they 

 run only in a single row. It is to be observed, however, that 

 teeth require to be closely examined, as in the case of the sea 

 trout the points bend alternately to either side, so as to pre- 

 sent rather the appearance of a thinly planted double row ; 

 whilst in the common trout the two lines of teeth are placed so 

 that a space in one row has a tooth opposite it in the other, 

 making the difference appear at first sight to be little more than 

 one of comparative closeness in the setting of the teeth. 



In regard to the position of these vomerine teeth, the en- 

 graving of the mouth of the common trout, given farther on in 

 this article, is somewhat inaccurate, resembling, in fact, more 

 nearly the appearance of the single row seen in the mouth of 

 the sea trout. 



The usual weight of the sea trout runs from one to three or 



