XI.—On the Development of the Feathers of the Duck during the Incubation Period

Abstract

Much study has already been devoted to the plumage of birds and its development, and the extensive literature to which this study has given rise might at first sight make it appear that no room is left for any new contributions to a subject which has already attracted so many investigators. The special branches of the subject, however, which have attracted most attention, have been:—(1) The histology of developing feathers, to which Studer, Davies, Wohlauer, and Bornstein have contributed; (2) pigmentation, investigated by STRONG; and (3) more recently what may be called the continuity between early “down” and adult feathers, a condition which does not appear to have been clearly realised before Jones and Gadow published the results of their researches. Recently also Waterston and Geddes, working on the embryology and anatomy of the Penguin, have touched incidentally on the appearance of down-papillæ and down at successive embryonic stages in the Penguin and the Duck; but, covering a wider field of research, they have not devoted to feather development in particular that careful observation and detailed study which the interest of the subject and the deficiencies of our knowledge appear to warrant.