_ 10.—Filoplumes or Hair- 
Feathers.—On the skin around 
the wingquills and tail-quills are 
found a few small, insignificant 
down-like or hair-like feathers 
known as filoplumes. Feathers of 
this hair-like character cover the 
body of almost all birds, and are 
best seen in a duck or fowl after 
it has been plucked of its contour 
and down feathers. In the ostrich 
they occur only around the larger 
feathers of the wing and tail, and 
are not found in all individuals. 
In most birds, down feathers 
occur underneath the contour 
feathers, but these are not repres- 
ented in the ostrich unless those 
here termed filoplumes are degen- 
erate down. 
B.—Tue Parts or a FEATHER. 
1.—Stem or Scapus.—This is 
the strong, middle supporting 
axis of the feather, and extends 
the whole length from one end to 
the other. The upper part or 
shaft bears the flue on each side, 
but the lower, or quill, is rounded 
and naked. 
2. Shaft or Rachis.—This is 
the long upper part of the stem 
which bears the flue. It is grooved 
on the inner face, and rounded 
on the outer. The depth of the 
inner groove varies much. In 
some birds it is scarcely noticeable, 
and the shaft as a whole is 
rounded ; in others it is very deep. 
3. Quill or Calamus.—The quill 
is the lower, rounded, hollow, 
naked part of the stem which does 
not bear any flue. When on the 
bird, part of it isembedded in the 
feather-socket. Sometimes the 
term quill is wrongly used for the 
entire stem or scapus. 
4. Flue.—The flue includes all 
the loose, soft, fluffy portion of 
the feather attached to each side 
of the shaft, and is made up’ of 
Barbs and Barhules. The flue in 
the ostrich corresponds with the 
web in ordinary compact feathers 
such as those of the fowl or duck. 
In these birds the parts of the 
flue are bound together by minute 
hocklets or barbicels on the 
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Fig. 1.—Diagram to illustrate the parts of a 
feather, the flue being represented on only one 
side. The pith sheath with the feather cones 
inside is shown extending a short distance up the 
shaft, having been preened away above. a, lower 
umbilicus ; /, feather cone; ¢, quill; ¢, upper 
umbilicus; e@, sheath of pith with feather 
cones ; f, barbule; g, shaft or rachis ;/, barb. 
