Family and Generic Differentiation. 327 



nor am I saying that the pectoral bands on tlie breast 

 of the Ringed Plover, or the peculiar pattern on its 

 head, do not serve a useful ruptive purpose in helping to 

 break up the continuity of its form. But what I am trying 

 to maintain is that the idea of protective-coloration is a con- 

 ception or even a hobby which is in danger of being ridden 

 to death — that it is only one phase of the whole question of 

 coloration, and that, taking the class of Birds as a whole, it 

 has probably always l)een a more or less lucky chance, so to 

 speak, if colour-pattern, born of genetic influences, happened 

 to. coincide with such a useful purpose as invisibility or 

 concealment. 



The idea in the past was that coloration or colour-patterns 

 were invariably impressed on the bird^s plumage from witli- 

 out, and hence systematists fought shy of using such 

 characters in classification. But there is always the other 

 side of the picture, namely, that birds, originally possessed of 

 a certain type of colour-pattern, unconsciously suited them- 

 selves to certain types of environment ; and if they did not — 

 Well ! there was always our old friend Natural Selection in 

 the background and — they disappeared. 



The Trogons occur to me as a good example of this other 

 side of the picture, because I happen to have made the 

 acquaintance of several species in their native haunts. The 

 Trogon peculiar to Cuba, for instance, is in reality a very 

 conspicuously coloured bird ; yet I have found it at times 

 very difficult to find in the forests, although I happened to 

 know that I was within a few yards of one from having 

 heard its peculiar pheasant-like cry. The reason for this 



coloration, we ought not to forget that our " brain-power " is of a very 

 different order to the " brain-power " of a bird or a mammal. It is, for 

 instance, more than possible that birds habitually see things as they 

 realbj look. It is in the highest degree unlikely that the brain of a bird 

 acts in the same way as ours in the direction of transforming the vision 

 of what the eye really sees into a picture of what the brain chooses to 

 think it sees, likes to think it sees, or has grown accustomed to think 

 it sees. 



