. The chordates. Chordata. Fig. 14. (Left) Cycloid scale of Salmo fario. (a) Anterior portion covered by overlap of preceding scales; (b) free portion covered only by pigmented epidermis. (denier) Ctenoid scale. (Right) Two ganoid scales. (From "Cambridge Natural History," Vol. VII. By permission of The Macmillan Company, publishers.) except some fishes, plates of dermal bone occur, sometimes more or less extensively over the body, as in the alligator, turtle, or armadillo, or at least as part of the skeleton of the head. The cavity of the mouth in all vertebrates is lined by infolde
. The chordates. Chordata. Fig. 14. (Left) Cycloid scale of Salmo fario. (a) Anterior portion covered by overlap of preceding scales; (b) free portion covered only by pigmented epidermis. (denier) Ctenoid scale. (Right) Two ganoid scales. (From "Cambridge Natural History," Vol. VII. By permission of The Macmillan Company, publishers.) except some fishes, plates of dermal bone occur, sometimes more or less extensively over the body, as in the alligator, turtle, or armadillo, or at least as part of the skeleton of the head. The cavity of the mouth in all vertebrates is lined by infolded skin whose two layers produce the calcareous teeth. Glands of many sorts are produced by the skin. The essential secretory layer of the gland is always of epidermal origin (Figs. 11, 12). Integumentary glands secrete mucus, oily substances, watery perspira- tion, milk, and poisonous or odorous substances. Cavities The trunk of the vertebrate is hollow. Its wall, the body-wall (pa- rietes), encloses at least two major cavities known collectively as the Chromatophores Epidermis. Fig. 15. Bony scales and horny scales. Diagrammatic sections perpendicular to surface of skin. (A) Overlapping bony scales of a fish. (B) Flat horny scales and (C) overlapping horny scales; especially characteristic of 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 Rand, Herbert W. (Herbert Wilbur), 1872-1960. Philadelphia : Blakiston
Size: 2172px × 1150px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollect, bookpublisherphiladelphiablakiston
