Page:The Zoologist, 4th series, vol 6 (1902).djvu/437

Rh 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 handsomest 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 perfect 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, insensibly masses the less saliently distinguished individuals together, so that those in whose plumage the light colouring is more en évidence than the dark go down as the light form, and vice versâ. Moreover, the more prononcé 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, however, as being less striking (though extreme at one end), is not, I believe, so much noticed as those various dunnish shades