. Chordate anatomy. Chordata; Anatomy, Comparative. EriAriEL ORCAN COMPACT CONNECTIVE TISSUE LOOSE 'connective TISSUE. BASAL PLATE B. D. Fig. 109.—A vertical section of the skin of an elasmobranch, showing five stages in the development of a placoid scale. The development of a placoid scale is essentially like that of a tooth. This fact taken together with the similarity of their structure sug- gests that teeth may have evolved from placoid scales. (Redrawn after Schimkewitsch, modified.) bones, scales, hair, feathers, horns—which serve for defense, support of tissues, or attachment of muscles
. Chordate anatomy. Chordata; Anatomy, Comparative. EriAriEL ORCAN COMPACT CONNECTIVE TISSUE LOOSE 'connective TISSUE. BASAL PLATE B. D. Fig. 109.—A vertical section of the skin of an elasmobranch, showing five stages in the development of a placoid scale. The development of a placoid scale is essentially like that of a tooth. This fact taken together with the similarity of their structure sug- gests that teeth may have evolved from placoid scales. (Redrawn after Schimkewitsch, modified.) bones, scales, hair, feathers, horns—which serve for defense, support of tissues, or attachment of muscles. The limy shells of molluscs and the chitinous exoskeletons of arthropods serve all three purposes. Among vertebrates, the placoid scales, which first appear in certain sharks of the Upper Devonian, are especially important because of their. 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 Neal, Herbert V. (Herbert Vincent), 1869-1940; Rand, Herbert W. (Herbert Wilbur), 1872-1960. Philadelphia : P. Blakiston's Son & Co.
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Keywords: ., bookcentury1900, bookpublisherphi, booksubjectanatomycomparative
