. The structure and life of birds. Birds; Evolution. VI FORM AND FUNCTION 147 When the quill is dry and hollow, the feather is in most ways a dead thing, but the fact that in some birds there is a change of colour without a moult, and without the loss of any part of the feather, shows that it has not entirely lost life. The stiff rod above the quill is the rachis or shaft (S). It is grooved. Fig 38^—Contour Feathers of Heron. (a) plume-like feather with little or no interlocking. (l>) pennaceous or perfect flight feather. , B, Barb; D, Downy ends of the lower barbs ; p, dried remains of Pul
. The structure and life of birds. Birds; Evolution. VI FORM AND FUNCTION 147 When the quill is dry and hollow, the feather is in most ways a dead thing, but the fact that in some birds there is a change of colour without a moult, and without the loss of any part of the feather, shows that it has not entirely lost life. The stiff rod above the quill is the rachis or shaft (S). It is grooved. Fig 38^—Contour Feathers of Heron. (a) plume-like feather with little or no interlocking. (l>) pennaceous or perfect flight feather. , B, Barb; D, Downy ends of the lower barbs ; p, dried remains of Pulp; q. Quill; s, Shaft or rachis ; s 7, After-shaft; v, Vane formed of the two webs on either .side ; u 1, Inferior umbilicus ; u z, Superior umbilicus. down the under-surface. The branches on either side are called barbs (B), and the barbs to right and left together form the vane of the feather. The barbs give rise to barbules—, little barbs on either side. The barbules end in barbicels—, still more diminu- tive barbs. The barbicels belonging to the barbules on the side of the barb that is nearer to the quill L 2. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Headley, F. W. (Frederick Webb), 1856-1919. London, New York, Macmillan
Size: 1964px × 1273px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectbirds, bookyear1895
