242 FEATHERS 
feathers consist of a series of flattened and comparatively thick 
compartments (see CoLouR). The distal part of the rami is often 
broadened and modified into a blue-producing structure, bearing 
no cilia. The rhachis of some of the median rectrices of certain 
BIRDS-OF-PARADISE, the LYRE-BIRD, and others, has no web, and 
consists of the shaft alone, while the same applies to the rictal 
bristles of most birds and the eyelashes of those that possess them, 
and to the peculiar strong and black quills of the Cassowaries’ wings. 
The expanded tip of the shaft of some feathers which gives the 
WAXWING its well-known name, and the similar structure of the 
neck-hackles of -some Galling, are special modifications. Nitzsch 
having stated (Pterylogruphie, p. 17; Engl. ed. p. 13) that the 
Contour-feathers of Struthio and Rhea have no cilia or hamuli, and 
that radii! are wanting on some of the rami in Cusuarius and 
Dromxus, the assertion has been often repeated as shewing an 
important differential character between Carinatz and Matitx, and 
assigning a more primitive stage to the plumage of the latter. But 
Fiirbringer has pointed out (Beitriige, p. 1482) that the statement 
needs considerable qualification. In fact, the remiges of [thea have 
numerous though small cilia, some of them even ending in hooklike 
nodules, while the nestling-feathers are abundantly furnished with 
well-developed cilia. The double shafts of Dromwus and Casuarius 
carry rami only on their distal portion, but the more basal rami 
of both webs bear numerous radii. The same applies to the 
plumage of the Penguins. We have therefore to conclude that 
the feathers of the fatitw and Sphenscide have undergone a 
degenerating process through the loss of hamuli, cilia, and occa- 
sionally of radii—a reduction that is most apparent on the remiges, 
but finding a parallel in numerous instances of reduced Contour- 
feathers. . 
The “Downs” are almost always concealed by the Contour- 
feathers, and are smaller, more fluffy, and more numerous. They 
may be characterized by the absence of hamuli, though generally 
possessing all the other parts of a typical feather, except that they 
frequently have no rhachis, in which case all their long rami start 
at the same level from a short calamus. ‘They thus approach the 
condition of the so-called nestling-feathers of many birds, and it 
can hardly be doubted that Downs represent a lower or more primi- 
tive stage than Contour-feathers, although of course many Downs 
are elaborate, and highly specialized. A peculiarly modified kind 
are the POWDER-DOWNS. 
The “Filoplumes” consist of a short calamus and a very thin 
hairlike rhachis with few or no rami. Such feathers are always 
associated with Contour-feathers, close to the base of which one or 
1 There is an accidental misprint in the English version of the passage (loc. 
eit.) of *‘barbicels” for barbules, 
