SALMON TRIBE. 495 



quite constant, but the migratory trout have two (and even three) more than the 



river-trout. In some waters river-trout remain small, and frequently retain the 



parr-marks all their lifetime ; at certain seasons a new coat of scales overlays the 



parr-marks, rendering them invisible for a time. When the salmonoids have 



passed this 'parr' state, the coloration becomes much more diversified. The males, 



especially during and immediately after the spawning- time, are more intensely 



coloured and variegated than the females ; specimens which have not attained to 



maturity retaining a brighter silvery colour, and being more similar to the female 



fish. Food appears to have much less influence on the coloration of the outer-parts 



than on that of the flesh ; the more variegated specimens being frequently out of 



condition, whilst well-fed individuals with pinkish flesh are of a more uniform, 



though bright, coloration. . . . The water has a marked influence on the colours ; 



trout with intense ocellated spots are generally found in clear rapid rivers, and in 



small open Alpine pools : in the large lakes with pebbly bottom the fish are bright 



silvery, and the ocellated spots are mixed with or replaced by X-shaped black spots ; 



in pools or parts of lakes with muddy or peaty bottom, the trout are of a darker 



colour generally ; and when enclosed in caves or holes, they may assume an almost 



uniform blackish coloration." A change of colour also takes place in the migratory 



species with the renovation of the scales, which occurs during their residence 



in the sea, the newly-grown portion of the silvery scales concealing the spots : and 



this change of coloration varies greatly according to the habitat of the individuals 



of some of the species. Variations of size are also common, these being for the 



most part dependent upon the abundance or otherwise of the food, and the extent 



of the area in which the fish dwell ; but differences in this respect also occur 



among the fish hatched from the same batch of spawn, and living under the same 



conditions. The variations in the form and proportions of the body, and more 



especially in the head and jaws, according to age, sex, and season, arc likewise very 



important, but cannot be noticed fully. 



The true salmon (S. solar), together with the kindred species 

 Salmon. . , . 



and the trouts, belongs to a group of the genus characterised by the 



presence of teeth on the whole length of the vomer during at least some period of 

 life. In the case of such a well-known fish — and also one which is generally 

 pretty easy to distinguish from its congeners — it will be unnecessary to give a 

 description. Dr. Gtinther gives, however, certain characters by which this fish 

 may always be identified, and among these the following may be noticed. The 

 scales on the tail are of relatively large size, and each transverse series running 

 from behind the fatty fin towards the lateral line contains only eleven, or occa- 

 sionally twelve, whereas in the trouts there are from thirteen to fifteen. Secondly. 

 the main part or body of the vomer carries a single series of small teeth, which, 

 with advancing age, gradually disappear from behind forwards, so that half-grown 

 and adult individuals have but a few remaining. Having a circumpolar distribution, 

 the salmon ranges southwards in America to 41° north latitude, and in the old 

 World to 43°, being unknown in any of the rivers flowing into the Mediterranean. 

 Salmon will grow to a length of between 4 and •*> feet, and commonly reach as 

 much as 40 lbs. Much heavier fish are, however, occasionally captured. Among 

 these may be mentioned a salmon of 60 lbs. from the Severn in 1889 ; one from the 



