96 THE STORY OF FISH tlFE. 



stomach of one of these fish were taken several 

 octopods, Crustacea and sea-squirts, a young bream, 

 twelve young boar-fishes, a horse-mackerel, and 

 one young of its own species ! 



The " skip-jack " {Tenmodern saltator), like some 

 carnivorous mammalia, seems to have developed 

 a thirst for killing for killing's sake. A voracious 

 feeder, destroying an immense number of other 

 shore fishes, yet it kills many more than it can 

 possibly eat. 



The common stickle-back is likewise a voracious 

 feeder. Dr Giinther relates that a "small stickle- 

 back, kept in an aquarium, devoured in five 

 hours' time seventy-four young dace, which were 

 about a quarter of an inch long and of the thick- 

 ness of a horse-hair. Two days afterwards it 

 swallowed sixty-two, and would probably have 

 eaten as many every day could they have been 

 procured." 



In some fishes, it is interesting to note, the 

 nature of the food actually influences the colour 

 of the flesh. The truth of this is particularly 

 well seen in the case of the salmon. These 

 fishes feed, at any rate at times, exclusively on 

 Crustacea, and the peculiar colouring substances 

 which pervade the system of these animals, 

 and to which they owe their characteristic red 

 colour when boiled, e.g. : lobster seems to under- 

 go similar chemical changes in the stomach, 

 and to pass from thence into the flesh of the 

 fish, imparting thereto its wonderful "salmon" 

 colour. 



The evidence of these various modifications of, 

 and departures from, the typical fish, leads very 



