324 Mr. P. R. Lowe 07i Coloration us a Factor in 



so ill the case of these colour-pictures, if one may so term 

 them, it is our business or the business of those who believe 

 in the importance of coloration as a factor in generic differ- 

 entiation, to distinguish between those which are simply 

 cryptic or concerned in the business of concealment and 

 those which are not so concerned. 



One may, of course, have both types of coloration in any 

 particular species. For instance, taking the Ringed Plover 

 group again, no one would deny that the Kentish Plover is 

 protectively coloured in an obliterative direction and in 

 harmony with its usual sandy or arid environments. But 

 this obliterative factor is merely an affair of shades and tones 

 of coloration which are superimposed upon the fundamental 

 colour-pattern cliaracteristic of the genus. The mere depth 

 of tones in desert situations is the direct outcome of the 

 greater intensity of light and the increased aridity, while 

 tlie tendency or the species in such environments to be 

 invisible is the result of a nicely adjusted process of counter- 

 shading, and both are the result of the reaction of the 

 organism to its immediate surroundings. The fundamental 

 colour-pattern is still tliei'e, although modified. 



Any organism, in fact, not only reacts to outward stimuli 

 but it has also an inherent power to act on, so to speak, its 

 own initiative; and this is a fact that in the matter of this 

 question of coloration we must not lose sight of. The fact 

 that coloration or colour-pattern as a serious aid to classifi- 

 cation in birds has been regarded with a certain amount of 

 contempt and suspicion has, I take it, arisen fi'om the 

 supposition that ail coloration or all colour-patterns are the 

 direct outcome of the action of external factors — or, to put it 

 shortly, that the coloration of birds is invariably cryptic and 

 a mere superficial response to environment in the direction 

 of enhanced invisibility. 



(2) The question of concealing coloration. 



Before, however, passing on to the consideration of colour- 

 pattern as a phylogenetic or generic clue, which is the chief 

 point of this discussion, I should like very briefly to notice 



