24 The Bird 
socket. This growth continuing, the down is lifted clear 
of the skin, being supported on the new structure, and 
Fic. 12.—Early stages in the development of a down feather, showing close 
resemblance to scale of fish or reptile. 
MOSS ALTER tS ne SL SIL 
Fic, 12a.—Later stages of Fig. 12, showing the first splitting up of the 
feather pulp. 
soon brushed off and lost. Thus, little by little, in 
shreds and tatters, the baby plumage is shed and replaced 
