SCIENCE OF FLAT-FISH, OR SOLES AND TURBOT. 113 



Imagine for a moment the chances of life possessed by a bright scarlet 

 animal among the snow-fields of Greenland, and one can see at once 

 the absolute necessity for this unvarying protective coloration. Even 

 a royal duke would scarcely venture to approve of flaring red uniforms 

 under such conditions. All the conspicuous creatures get immediately 

 weeded out by their carnivorous enemies, owing to their too great 

 obtrusiveness and loudness of dress ; while those alone survive which 

 exactly conform to the fashionable whiteness of external nature. So, 

 too, in the desert every bird, lizard, grasshopper, butterfly, and cricket 

 is uniformly dressed in light sand-color. The intrusive red or blue 

 butterfly from neighboring flowery fields gets promptly eaten up by 

 the local bird, whose plumage he can not distinguish from the sand 

 around it. The intrusive scarlet or green bird from neighboring 

 forests finds the bread taken out of his mouth by the too severe com- 

 petition of his desert brethren, who can steal upon the native grass- 

 hoppers unperceived, while he himself acts upon them like a red dan- 

 ger-signal, and is as sedulously avoided by the invisible insects as if 

 he meant intentionally to advertise in flaming posters his own hostile 

 and destructive purpose. 



In short, sand-haunting creatures are and always must be neces- 

 sarily sand-colored. 



A few tropical flat-fish, however, living as they do among the brill- 

 iant corals, pink sea-anemones, gorgeous holothurians, and banded 

 shells of the Southern seas, are beautifully and vividly spotted and 

 colored with the liveliest patterns. In this case the necessity for pro- 

 tection compels the fish to adopt the exactly opposite tactics. All 

 those young beginners which happen to show any tendency to plain 

 brown coloring are sure to be recognized as fish, and get promptly 

 eaten up among their bright surroundings ; only those which look 

 most like the neighboring inedible and stinging nondescripts stand 

 any chance of escaping with their precious lives. A Quaker garb 

 which would easily pass unobserved in the murky English Channel 

 would become at once conspicuous by contrast among the brilliant 

 organisms of Amboyna or Tahiti. This beautifully proves the rela- 

 tivity of all things, as philosophers put it. Ordinary people express 

 the same idea in simpler language by saying that circumstances alter 

 cases. 



Most of our English flat-fish lie consistently on one side, and that 

 the left ; they keep their right eye always uppermost. But the tur- 

 bot and the brill reverse this arrangement, having the left side on top 

 and colored, while the right side is below and white. Two other fish, 

 known as the fluke and the megrim, but not received in polite society, 

 follow the example of their fashionable friends in this respect. But in 

 no case are these habits perfectly ingrained ; now and then one meets 

 with a left-sided sole or a right-sided turbot, which looks as though a 

 great deal were left to the mere taste and fancy of the individual flat- 

 vol. xxix. 8 



