148 SALMON AND TROUT. 



below, as the keeper, who was watching, said, 'hke a great 

 porpoise.' 



As to the question, 'Will salmon live and thrive entirely in 

 fresh water — that is, in lakes and ponds which have no com- 

 munication with the sea?' some observations will be found in 

 previous editions. 



The principal characteristics of the true salmon are : 



Length of head compared with whole length of fish as i to 5. Body elongated; 

 dorsal and abdominal line about equally convex. Lateral line near middle of 

 body, dividing it about equally. Fleshy portion of tail slender. Scales, mode- 

 rate sized, oval, and thin, easily removed when young, adherent when old. 

 Teeth, stout, pointed, and curved, one Hne on each side of upper jaw, one line 

 on each bone of palate, one line on vomer or central bone in roof of mouth 

 when quite young (loses a large portion on first visit to salt water, and gradually 

 all, or all but one or two on most forward point of bone), on line one each side 

 of lower jaw, one line on each side of tongue (occasionally two lines on each 

 side of tongue). 



Fin rays : D. 13: P. 12: V. 9: A. 9: C. 19. Vertebrae, 60. 



THE BULL TROUT {Sahno eriox). 



Although differing in many respects from the true salmon, 

 and constituting, of course, a distinct species, yet in many of 

 its habits, if not, indeed, in all, the bull trout bears so close a 

 resemblance to the latter fish that the history of the one may, 

 to a great extent, be taken as the history of the other, and all 

 the laws relating to salmon apply equally to the bull trout and 

 their young, under whatever local names they may be known. 



Like the salmon, the bull trout ascends rivers for the purpose 

 of spawning, deposits its ova on similar spawning grounds, and 

 after the process returns to the sea to restore its exhausted 

 energies and increase in weight and bulk. So far as I am 

 aware nobody has actually verified — that is by the same absolute 

 means as in the case of the salmon — the periodical growth-rate 

 of the bull trout between its various migrations. But as I have 

 caught several hundreds of bull trout myself in the Usk averag- 

 ing from four up to twenty pounds and never remember to 

 have caught one of much less than the first-named weight, it is 

 only reasonable to conclude that this is the size at which they 



