3,26 ;Mr. P. R. Lowe 07i Coloration as a Factor in 



ancestral living representative of this group, we may sup- 

 pose that this species stands at the point of divergence of the 

 two branches into which this family seems to have split. 

 In the germ-cells of this species or its ancestors there are 

 or were presumably resident three potential colour-factors 

 — red, yellow, and black (this last independently distributed) ; 

 and out of these, the colour-scheme characteristic of any or 

 all the genera of the family could be constructed by various 

 combinations (in the direction of either addition or loss) of 

 these primary colour-factors. Incidentally, it is somewhat 

 tempting to suggest that there were also two factors for the 

 form and shape of the bill — a Pseudonest07'-hi\l factor and a 

 Drepanis-hiW factor. 



In connection with this subject of particular groups of 

 birds having particular colour-schemes, or having particular 

 colour-factors proper to them, Mr. Witmer Stone "^ has 

 recently called attention to the absence of red among the 

 Jays or of green among the Thrushes. He has also called 

 attention to certain conspicuous colour-patterns which it is 

 difficult to reconcile with any plan for concealment or 

 indeed with any scheme of a breaking-up or ruptive nature. 

 For instance, he quotes the metallic blue or green speculum 

 in the Ducks or the blue and black wing-patch in the Jays. 



In making these remarks on this aspect of coloration, I 

 am not, of course, trying to belittle the patent and manifest 

 facts of concealing coloration, which seems obvious enough 

 in certain groups of birds. I am not quarrelling with 

 the theory of countershading as set forth by Thayer f ; 



* "The Phylogenetic Value of Colour-characters in Birds," by Witmer 

 Stone, A.M., Journ. Acad. Nat. Sci. Philad. 2nd series, vol. xv. 

 1912, p. 314. 



t If Thayer had done nothing else than accentuate the difference 

 between how we see things with the brain and how we see them with the 

 eye, he would not have written his very instructive book in vain. We 

 have grown so accustomed to habitually see things with the brain that 

 it is only the trained artist who, as a rule, and then only by a certain 

 effort, can switch off his brain and see things as they really look, instead 

 of in the way we are accustomed to translate them by means of our 

 brain. Therefore, in thinking of questions like that of concealing- 



