. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 286 SALLY HUGHES-SCHRADER metaphase are shown in Figure 38. At the first meiotic division the 2 Xs pass to one pole, the Y to the other; the second metaphase accordingly shows either 15 or 16 elements (Figs. 32 and 33). /. Second polarization Leptotene, zygotene, and early pachytene stages correspond closely to those of the other species studied. In late pachytene however, the chromosomes become diffuse in outline, are almost unstainable in gentian violet and haema- toxylin, and give but a faint Feulgen reaction. When later
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 286 SALLY HUGHES-SCHRADER metaphase are shown in Figure 38. At the first meiotic division the 2 Xs pass to one pole, the Y to the other; the second metaphase accordingly shows either 15 or 16 elements (Figs. 32 and 33). /. Second polarization Leptotene, zygotene, and early pachytene stages correspond closely to those of the other species studied. In late pachytene however, the chromosomes become diffuse in outline, are almost unstainable in gentian violet and haema- toxylin, and give but a faint Feulgen reaction. When later they again become stainable, the bivalents, already greatly shortened compared to the long threads of early pachytene, are found peripherally distributed close to the nuclear mem-. FIGURE 35. Choeradodisrhombicollis. Second polarization; chromosomes loosely aggregated near division centers. Haematoxylin. brane (Fig. 34). Asters form about the centers, and these separate quickly to opposite sides of the nucleus, which may elongate slightly along the inter-center axis (Fig. 35); but the polarization is always slight and many do not reach the polar regions. So late is the polarization relative to the stage of contraction of the chromosomes that the latter appear to move as wholes. In a few nuclei, however, polarization occurs while the chromosomes are still relatively long, and then, as in Paratenodera, the ends alone orient to the center. //. Kinetochore movements On the breakdown of the nuclear membrane the spindle forms in the nuclear area and quickly elongates. Due to the large size of the nucleus and the conse-. 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 Rattr
Size: 1862px × 1342px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
