File:Image from page 593 of "On the anatomy of vertebrates (electronic resource)" (1866) (14752454051).jpg

Identifier: b20416039_001 Title: On the anatomy of vertebrates [electronic resource] Year: 1866 (1860s) Authors: Owen, Richard, 1804-1892 Subjects: Anatomy, Comparative Vertebrates Fishes Reptiles Mammals Birds Publisher: London : Longmans, Green Contributing Library: Wellcome Library Digitizing Sponsor: Wellcome Library

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Text Appearing Before Image: Ctenoid scale, xxii. N N 2 548 ANATOMY OF VERTEBRATES. 364

Text Appearing After Image: Ganoid scales, Arriblypterus. termed < placoid, fig. 365, ganoid, fig. 364, < cycloid, fig. 362,4 ctenoid, fig. 363. In the first and second kinds bone-earth predo-minates, and the scales are as hard as teeth; in the two latter kinds the earth is in less quantity, so thatthe scale is flexible: it is rarely want-ing. The kinds of scale graduateinto each other. Most flexible scalespresent two structures: one next thederm is composed of gristly lamina?,usually firm and elastic, fig. 360, c;the superficial portion, ib. d, islaminated and hardened by interla-mellar calcareous granules.1 In the posterior or exposed partof the scale of a Carp there is a peripheral osseous layer, deve-loping the outer markings or projections of the scale, fig. 360, d; a middle laminated layer, with365 calcareous granules, ib. e; and the internal layer oflaminae of structureless car-tilage, ib. c. In the Tunny (Thynnusvulgaris) the scales are com-posed of fine, partially ossi-fied, lamina?, between which

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