NATURAL SELECTION 



there is but one which is not green, and this 

 kind conceals itself during the daytime in holes. 

 Flat fish, like the skate and flounder, are col- 

 oured like the gravel beneath them. Fishes 

 which live among gorgeous coral reefs are mag- 

 nificently tinted. The brilliant red hippocampi 

 of Australia dwell among seaweed of the same 

 colour. And numerous other examples from 

 the vertebrate sub-kingdom are given by Mr. 

 Wallace, from whose remarkable essay the ex- 

 amples here given are culled. 



Before going farther, let us note how com- 

 pletely these interesting phenomena are in har- 

 mony with the theory of natural selection. The 

 variability of the hues of domestic animals de- 

 scended from a monotonously coloured wild 

 species shows that there is no direct physiolo- 

 gical necessity for the production of animals of 

 a single given style of colouring. But it is tol- 

 erably obvious that in the struggle for existence 

 the most conspicuous among those animals 

 which serve as food for others will be the soon- 

 est detected, killed, and eaten ; while in general 

 the most conspicuous carnivorous animals will 

 be the most easily avoided, and hence will be 

 the most likely to perish for lack of sustenance. 

 And while it is not universally true of the 

 higher animals, as it is of the lower animals and 

 plants, that a much greater number perish than 

 survive, the destruction of life is nevertheless 



VOL. in 23 



