such patterns make their wearer conspicuous. So immeasurably great, in the 

 case of most animals, must be the value of inconspicuousness, that such de- 

 vices as achieve this to the utmost imaginable degree, upon almost every liv- 

 ing creature, demand no further reason for being (although doubtless serving 

 countless other minor purposes). 



The theory of Natural Selection is based on the belief that organisms are 

 susceptible of modification limited only by the duration of the circumstances 

 causing it, or by the attainment of ultimate perfect fitness to environment. 

 Now, since the same circumstances would always be best met by the same 

 characters in an organism, we are not surprised to find aU animals, of how- 

 ever widely different orders, resembling each other in shape and color in evi- 

 dent proportion to their degree of having the same habitat and habits. The 

 whole class of mammals, dwelling mainly on the ground, have mainly ground 

 color, and a form varying no more than their situations and habits. The 

 same thing is equally true of thousands of species of birds, of fishes, reptiles 

 and insects; even mammals, if they lead a fish's life, like the cetaceans, have 

 the general shape and color of fishes. (A parallel case is that of humming- 

 birds and hawk moths.) No fish of the open ocean is permitted by Nature 

 to wear any essential color-distinction from his hundreds of neighbor species. 

 He has, for aU we know, the same need of "warning colors," "banner marks," 

 etc., as any land animal; but Nature vouchsafes him no pin-point of color be- 

 yond that of the sky-lit deep-sea water. The same is true of the inhabitants 

 of the aerial ocean spaces. Save for a good many small, bright-colored dec- 

 orations, mainly of the beaks, worn by such species as breed where such col- 

 ors abound. Nature allows them no colors which are not those of sea surfaces, 

 clouds and sky, or of somber cliffs; or, for the diving ones, dim water-colors, 

 more like those of the fishes themselves. In short, the so-called "nuptial 

 colors," etc., are confined to situations where the same colors are to be found 

 in the wearer's background, either at certain periods of his life, or all the time. 

 Apparently, not one "mimicry" mark, nor one "warning color" or "banner 

 mark," nor one of Gadow's light-and-shadow-begotten marks, nor any "sex- 



5 



