UTILITY OP MEMORANDxV. 55 



which is common to most of the large Scottish and Irish inland 

 waterSj and which is pronounced by Mr. Agassiz to be distinct 

 from any of the continental Lake Trout — these teeth extend 

 along the whole length of the vomer. 



And in the Lochleven Trout [Salmo Levenensis sive Ccecifer, 

 Walker and Palmer), if it be a distinct species from the Common 

 Trout {Salmo Fario), as appears to be conceded — although I must 

 say I doubt it^ as I do the Gillaroo^ which, however, is more 

 doubtful — there are thirteen teeth on the vomer, extending 

 through its whole length. 



It would be well, indeed, if American anglers would take a 

 little pains about the examination of these points, and would 

 note them down in their tablets — in which, doubtless, they insert 

 the weight of their captives — together with the relative propor- 

 tion of the length of the head to that of the entire body ; the 

 form of the gill-covers ; and relative position of the eye to a 

 line drawn from the front teeth to the lower posterior 

 angle of the operculum or sub-operculum, as it may be ; the 

 number of rays in each of the several fins ; and especially the 

 form of the caudal fin-tail — whether forked, concave, square, or 

 convex. 



A very few memoranda on such points as these, accurately 

 recorded, and assisted, where practicable, by the roughest 

 sketch, would be of greater utility to the cause of science, than 

 can be readily imagined; and we should undoubtedly soon 

 arrive at facts of great importance, and perhaps discover some 

 new and interesting species of this most interesting family. 



At all events, we should not be tantalised by information so 

 vague and indefinite as that conveyed in a note to the Appendix, 



