Pelagic Organisms 



remarkable case of protective colouring. Un- 

 fortunately, nearly all the more highly developed 

 forms display conspicuous pigment (as in most 

 jelly-fish) in some part of the body. 



" An animal floating about in the sea," writes 

 Beddard, " perfectly transparent, but decked with 

 dense black patches, of the size of saucers, would 

 betray its whereabouts even to the least observant ; 

 if the observer were stimulated by hunger or fear, 

 the conspicuousness would not be lessened. . . . 

 Besides the internecine warfare which is con- 

 tinually going on amongst the smaller surface 

 organisms, they are devoured wholesale by the 

 larger pelagic fish, and by whales and other 

 Cetacea. A whale, rushing through the water 

 with open mouth and gulping down all before 

 him, is not the least inconvenienced by the 

 invisibility of the organisms devoured in such 

 enormous quantities ; nor do a solid phalanx of 

 herring or mackerel stop to look carefully for 

 their food : they take what comes in their way, 

 and get plenty in spite of * protective absence of 

 colouration.' 



" If the transparency of the pelagic organisms be 

 due entirely to natural selection, it is remarkable 

 that there is so little modification in this direction 

 among the species inhabiting the bottom at such 

 depths as are accessible to the sun's rays ; the 

 advantage gained by this transparency and con- 

 sequent invisibility would be equally great. And 

 N 193 



