Prince. — The Red Flesh of the Salmons 53 



as pervades the muscle tissues of salmon and trout. 

 Herring, menhaden and mackerel, though feeding almost 

 solely upon copepods, schizopods, and other small crus- 

 taceans, rich in red coloring matters, are not red-fleshed. 

 The chief muscles of the trunk in these fishes are not 

 red, though a thin superficial band of brown muscle ex- 

 tends beneath the skin along each side.* Cod, haddock 

 and other fish with characteristic pale or white flesh, de- 

 vour much food, like crabs, lobsters, etc., containing red 

 lipochromes, yet their muscles are not tinted in conse- 

 quence. * 



Food Does Not Color Muscles Directly. 



The occurrence of bright red muscular tissues is very 

 peculiar, and cannot be traced directly to the food in a 

 great many fishes, if indeed in any fishes at all. It is 

 remarkable, for example, that the ancient type of fish, 

 a Palaeozoic type, Ceratodus, found in Australia, has 

 deep red flesh, and the name 'Dawson salmon' was given 

 to the Australian Osteoglossum, a fish midway between 

 a herring and a salmon, owing to its pink flesh, and edi- 

 ble qualities. Professor Moseley, of Oxford, noticed in 

 dissecting a shark, during the "Challenger" cruise, that 

 while the great muscles of the trunk were pale or white, 

 the superficial muscular layer was a bright red. Professor 

 McMurrich described, I think in Syngnathus, the pipe 

 fish, possessing pale muscles, a minute dorsal strip of 

 muscle used in raising or depressing the single dorsal fin 

 as pink or red. The sturgeon has flesh of different col- 

 ors, red, white, etc., so that it has often been described 

 as "fish, flesh and fowl," (white, red and yellowish). 

 Hence, in view of the fact that white-fleshed fish may 

 feed largely on crustaceans, which are rich in red color- 

 ing matters, and that red-fleshed fish by no means feed 



*Miss M. I. Newbigin ("Salmon Investigations" Report, Scot. Fishery 

 Board, 1898), observes (p. 162) : "The herring feeds habitually on small 

 Crustacea, so that it might be said that the pigments of the salmon are 

 obtained indirectly from the herring, which forms its food; but of these 

 pigments there is no reason to believe that the red exists in the herring 

 ., I was unable to find any trace of it, either in the muscle or, in 

 the viscera." 



