46 



THE SCOTTISH NATURALIST 



group of reptiles, that it was natural to assume that in 

 taking over many reptilian structures birds took over also 

 reptilian scales, and that in process of time the flat plates 

 became converted, in whole or in part, into feathers. 



Fig. 3. — Succession of first down and quill feathers in tail of Mallard, showing the 

 relationship and continuity of the two. C, " cones " in shaft of down feather. 



DESCRIPTION OF FIGURES ON PAGE OPPOSITE. 



Fig. Upper Left. — Succession of first down, second down, and tip of quill feather 

 from wing of Chinese Gosling. 



Fig. Upper Right. — End of second down feather of Chinese Gosling near its 

 junction with tip of true flight feather. 



Fig. Lower Left. — Nestling tail of seven days' Mallard Duckling showing first 

 down feathers being pushed out by growth of true quill feathers. 



Fig. Lower Right. — Nestling tail of Mallard at middle of fifth week, showing 

 development of true tail-quills, to the tips of which the first down feathers are 

 still adhering. 



