HISTORY OF FEATHERS, WITH REFERENCE TO MALLARD 45 



THE HISTORY OF FEATHERS, WITH SPECIAL 

 REFERENCE TO THE MALLARD.^ 



Feathers are found on birds and on birds only, and 

 because of this rigidly limited distribution much discussion 

 has arisen as to how they must first have developed, and 



FiG. I. — Part of barb from first down 

 feather of sixteen-days'-old Mallard, 

 showing barbules specially twisted at 

 their origin. Magnified 25 diameters. 



Fig. 2. — End of a barbule from first 

 down feather of twenty- three 

 days' Mallard, showing cilia. 

 Magnified, 250 diameters. 



as to the structures in other groups of animals, with which 

 they are comparable. An understanding of evolution and 

 its significance has made so clear the origin of the first 

 birds, in the far past, from some advanced member of the 



1 Abstracted from an important paper on " The Nestling Feathers of 

 the Mallard, with Observations on the Composition, Origin, and History 

 of Feathers" {Proc. Zool. Soc. Londojt, 1921), by Prof. J. Cossar Ewart, 

 M.D., F.R.S., to whom and to the Council of the Zoological Society of 

 London we are indebted for the loan of the blocks of the accompanying 

 figures. 



