632 FISHES. 



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 ; but they 

 reappear in time, or are distinct as soon as the scales are 

 removed. When the Salmones have passed this " Parr " 

 state, the coloration becomes much 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. Pood appears to have less influence on the coloration 

 of the outer parts than on that of the flesh ; tlius the more 

 variegated specimens are frequently out of condition, whilst 

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

 though bright coloration. Chemistry has not supplied us yet 

 with an analysis of the substance which gives the pink colour 

 to the flesh of many Salmonoids ; but there is little doubt 

 that it is identical with, and produced by, the red pigments 

 of many salt- and fresh-water Crustaceans, which form a 

 favourite food of these fishes. 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 tlie large lakes with peljbly bottom the fish 

 are bright silvery, and the ocellated spots are mixed vsdth 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. 



The change of scales (that is, the rajoid reproduction of 

 the worn part of the scales) coincides in the migratory species 

 wdth their sojourn in the sea. The renovated scales give 

 them a bright silvery appearance, most of the spots disappear- 

 ing or being overlaid and hidden by the silvery scales. Now, 

 some of the species, like S. fario, inhabit all the different 



