. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates -- Anatomy. 44 COMPARATIVE MORPHOLOGY OF VERTEBRATES. specialized portion of a continuous axis, but it is not possible to carry the comparison into details. The idea of Oken that the skull is a com- plex of three or four vertebrae has long been overthrown. The skull differs markedly from the vertebral column in the presence of numerous membrane bones. VERTEBRAL COLUMN. The notochord (p. 12) is the foundation around which the verte- bras and the posterior part of the skull are developed. It is a cylin- dm. FIG. 37.—Section
. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates -- Anatomy. 44 COMPARATIVE MORPHOLOGY OF VERTEBRATES. specialized portion of a continuous axis, but it is not possible to carry the comparison into details. The idea of Oken that the skull is a com- plex of three or four vertebrae has long been overthrown. The skull differs markedly from the vertebral column in the presence of numerous membrane bones. VERTEBRAL COLUMN. The notochord (p. 12) is the foundation around which the verte- bras and the posterior part of the skull are developed. It is a cylin- dm. FIG. 37.—Section of developing vertebra of 45 mm. Amblystoma. c, cartilage of inter centrum; csl, outer chorda sheath; cs2, inner chorda sheath; dm, dura mater; e, epithelioid layer of notochord (elastica interna); end, endorhachis, torn from wall of vertebral canal; np, neurapophysis (ossified); ns, neural spine of preceding vertebra; nt, notochord; sc, spinal cord sd, subdural space. drical rod of entodermal origin, without segmentation,1 extending from the infundibulum (see brain) to the posterior end of the body. Its cells become vacuolated and at length most of the protoplasm, together' with the nuclei, migrate to the surface of the cord, where they appear like an epithelium, which, together with its basal membrane, is called the internal elastic membrane (elastica interna, fig. 37, e}. 1 Segmental undulations occur in the notochords of some mammals, but their significance is not 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 Kingsley, J. S. (John Sterling), 1854-1929. Philadelphia, P. Blakiston's son & co.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1912
