246 THE ANGLEK-NATURALIST. 



Secondly, differences in the arrangement of the teeth. 

 These will be useful to the angler principally as furnishing 

 a ready means of distinguishing the Sea-Trout from the 

 true Salmon and the Bull-Trout the difference between 

 the teeth in the two latter species being little beyond .a 

 question of size. 



The distinguishing characteristic in the dental arrange- 

 ment of the Sea-Trout is, that the teeth on the vomer, 

 or central bone in the roof of the mouth (marked 1 in 

 the engraving*), are more numerous 

 than in either of the other species, and 

 often remain, as here drawn, extending 

 a considerable distance along the bone, 

 whilst in the true Salmon and Bull- 

 Trout they are almost all lost upon the 

 first migration to the sea, only two or 

 three being left on the most forward end 

 of the bone; and these, in old fish, are frequently re- 

 presented by a single tooth, or entirely disappear. Even 

 in the Sea-Trout, however, the teeth on the vomer dimi- 

 nish in numbers as the fish gets older, and will often be 

 found in a cluster only at the end of the bone ; but they 

 are always retained in greater numbers than in the true 

 Salmon and Bull-Trout. The teeth generally, also, of the 

 Sea- Trout are finer and more numerous than in the other 



* The number of rows and general arrangement are veiy similar in 

 the several species of the genus Salmo. For names of teeth, bones, 

 &c., see p, 35. 



