. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 264 ALLAN SCOTT. FIGURES 13-16. Egg outlines and corresponding surface granule patterns during four stages of cleavage from the sphere stage to early indenture. Patterns shrink two-dimensionally in Figures 13-14 but only in directions around the furrow in Figures 15 and 16. Furrow surface During the earliest phase of cytokinesis the presumptive furrow region flattens around the equator. This is the first phase of surface shrinkage in the potential furrow region. Equatorial shrinkage starts even before cell elongation is appa
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 264 ALLAN SCOTT. FIGURES 13-16. Egg outlines and corresponding surface granule patterns during four stages of cleavage from the sphere stage to early indenture. Patterns shrink two-dimensionally in Figures 13-14 but only in directions around the furrow in Figures 15 and 16. Furrow surface During the earliest phase of cytokinesis the presumptive furrow region flattens around the equator. This is the first phase of surface shrinkage in the potential furrow region. Equatorial shrinkage starts even before cell elongation is apparent. Figure 13 represents an egg just before cleavage is to start. It shows a wide granule pattern on one region of the future furrow surface, while Figure 14 shows the same region a little later when the egg is still nearly spherical. Comparison of Figures 13 and 14 shows that equatorial shrinkage is two-dimensional at this stage in the plane of the surface. The furrow area shrinks along lines of longitude as well as around latitudes. At least one-tenth of the egg surface is surely involved in this shrinkage which represents a band about 15 micra wide around the equator. A longitudinal expansion of the furrow begins at the cylinder stage (Figs. 15 and 22) but its extent can only be appreciated when granule positions are projected to the furrow margin. Views of the exact center of the furrow show the plastic deformation of the sur-. 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 Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory (Woods Hole, Mass. ). Annual report 1907/08-1952; Lillie, Frank Rattray, 1870-1947; Moore, Carl Richard, 1892-; Redfield, Alfred Clarence, 1890-1983. Woods Hole, Mass. : Marine Biological Laboratory
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