. Chimæroid fishes and their development. Fishes; Chimaeridae. Fig. 66.—Sagittal section of gastrula in which the embryo is appearing. fl^ Afchenleron. '1 Region of oulermost maTgin of ventral lip of blastopore. ptii, Posterior mass of cells (in rwsition of ventral lip of blastopore). ^'Pt Region of blastopore. '". Thickening in medullary plate of embryo. .*"'. Segmentation cavity. m-. :& pm r Fig. 66 A.—Section (lateral) parallel to the preceding. the later, a portion of its material, at least, being represented b}^ the spongy mass of cells which now forms the floor of the arche
. Chimæroid fishes and their development. Fishes; Chimaeridae. Fig. 66.—Sagittal section of gastrula in which the embryo is appearing. fl^ Afchenleron. '1 Region of oulermost maTgin of ventral lip of blastopore. ptii, Posterior mass of cells (in rwsition of ventral lip of blastopore). ^'Pt Region of blastopore. '". Thickening in medullary plate of embryo. .*"'. Segmentation cavity. m-. :& pm r Fig. 66 A.—Section (lateral) parallel to the preceding. the later, a portion of its material, at least, being represented b}^ the spongy mass of cells which now forms the floor of the archenteron, ti; that finally (/') there is evidence that the posterior rim of the blastoderm is rolling inward, the surface of the blastoderm growing more rapidly in this region than the lower layer with which it is connected. Detailed examination of the sections, however, leads us to the belief that the process of inrolling extends only as far as the point / (fig. 66); just above this the inrolled rim of the blastoderm merges with the cells arising from the germinal wall, and from this point inward openings occur between the cells and communicate with the archenteron. The .section (fig. 66 a) already' referred. 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 Dean, Bashford, 1867-1928. Washington, D. C. , Carnegie Institution of Washington
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectfishes, bookyear1906
