COLOUBING OF STEBCOBAEIVS CBEPIDATUS. 371 



feathers of the tail, absent in the young bird, and by every other 

 indication — all the individuals here described were old birds in 

 mature plumage. They were all established in one locality, and 

 I was able to compare most of them with each other. I think, 

 therefore, that, though some of my colour-terms may not be quite 

 accurate — in describing colours there is generally some difference 

 of nomenclature — yet that the variation between the different 

 forms is properly brought out. Without my seeking it, the list 

 includes the two extreme forms, as I believe them to be, of dark 

 and light — the former represented by a uniformly dark brown 

 bird, the latter by one having the whole under surface of the 

 body, as well as the sides and nape of the neck, of a beautiful 

 cream colour, by virtue of which, and of the salient contrast 

 exhibited between this and the dusky upper surface, it is 

 extremely handsome, not to say beautiful — one of the hand- 

 somest of all our British birds, in my opinion. Both the extreme 

 forms are uncommon, whilst of the many forms between them 

 hardly any two seem to me to be quite alike. The extreme 

 forms are, or much more so; and this would make them more 

 numerous than any one of the others, though less so than all of 

 these collectively. Also the extreme light, or handsome, form 

 seems to me to be commoner than the extreme plain one. 

 Should not a bird like this be described as multimorphous 

 rather than as dimorphous ? I believe that there exists as per- 

 fect a series between the two extreme forms as between the least 

 eye-like and the most perfect eye-feather in the tail of the 

 Peacock, as pointed out by Darwin, and exhibited in the Natural 

 History Museum at South Kensington. The eye, however, in- 

 sensibly masses the less saliently distinguished individuals 

 together, so that those in whose plumage the light colouring is 

 more en evidence than the dark go down as the light form, and 

 vice versa. Moreover, the more prononce a bird is in one or 

 another direction the more it is remarked ; so that perhaps the 

 intermediate shadings are forgotten, on the same principle as 

 that by which extreme characters in any direction are more 

 appreciated than less extreme ones by the breeders of fancy 

 birds — pigeons, poultry, &c. The uniform brown form, how- 

 ever, as being less striking (though extreme at one end), is not, 

 I believe, so much noticed as those various dunnish shades 



