On the phylogeny of hair. American Museum novitates ; no. 1820
Supplemental Materials
Date
1957
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New York, N.Y. : American Museum of Natural History
DOI
DOI
Abstract
"Thickenings of the epidermis that project downward and upward, the outward projections of which are surrounded by circular ditches, and that perform a mechanico-sensory function are considered forerunners of hairs (prototriches). Findings of previous observers on such structures in fishes, tailed amphibians, and reptiles are combined with new observations on skin projections of some Salienta to devise a theory of hair and scale evolution. The most primitive prototriches are simple downward thickenings of the epidermis (fishes). In the next stage, a small corium papilla pushes into the epidermal downward thickening and a slight external elevation is added (tailed amphibians). Further phases involve keratinized, sharp, conical projections with circular ditches (coni circumfossati) in spadefoot toads. In some reptiles sensory bristles of similar structure present another phase. The prototriches in tailless amphibians are arranged in characteristic patterns on the warts. Transitional phases between protothrix-studded warts and scale-hair combinations can be shown. The theory is advanced that while the hairs derive from the prototriches, the scales of Amniota derive from warts of amphibians"--P. 14.
Description
15 p. : ill. ; 24 cm.
Includes bibliographical references (p. 14-15).
Includes bibliographical references (p. 14-15).
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