. Elements of the comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates -- Anatomy. IIS IS c1 I Fin. 12.—Six STAGES IN THE DEVELOPMENT OF THE FEATHER. (Mainly after Th. Stucler.) On, derma ; SM, stratum Malpighii ; Se, stratum corneum ; S'M1, Scl, extensions of these tissues into the feather-papilla, Pap ; FK, feather-germ ; F, Fi, feather- follicle ; P, pulp ; Fal (SM1), folds of the Malpighian layer extending into the feather-germ, and enclosed externally by the horny layer, HS (Sc^) : both layers are seen in the transverse section (0) ; FSp, quill of feather, which breaks up
. Elements of the comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates -- Anatomy. IIS IS c1 I Fin. 12.—Six STAGES IN THE DEVELOPMENT OF THE FEATHER. (Mainly after Th. Stucler.) On, derma ; SM, stratum Malpighii ; Se, stratum corneum ; S'M1, Scl, extensions of these tissues into the feather-papilla, Pap ; FK, feather-germ ; F, Fi, feather- follicle ; P, pulp ; Fal (SM1), folds of the Malpighian layer extending into the feather-germ, and enclosed externally by the horny layer, HS (Sc^) : both layers are seen in the transverse section (0) ; FSp, quill of feather, which breaks up above into a tuft of rays or barbs (HSt) ; sec, sec, secondary rays (barbules) arising from the latter ; R, rachis ; V, vexillurn. For further details as to the different stages A-F, compare text. If one supposes that in Fig. A the papilla grows and becomes flattened and bent downwards posteriorly, and that ossification occurs in the dermal portion, the essential mode of development of a scale would be arrived at. begin to proliferate rapidly, giving rise to a series of radial folds arranged along a central axis, which extend inwards towards the pulp, and are immediately bounded by the horny layev (Fig. 12, C, Fed (SM1) and HS (Scl). These folds then become comified and separated from the surrounding cells, and, by a gradual drying of the. 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 Wiedersheim, Robert, 1848-1923; Parker, W. N. (William Newton), d. 1923. London, New York, Macmillan
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Keywords: ., bookcentury1800, bookdecade1880, bookpublisherlondonnewyorkmacmi
