. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. HARLEQUIN LOBE OF DISCOCEPHALINI 281 lobes. In the former the sex chromosomes at both metaphases become detached from the autosomal aggregate, which then is displaced toward the side of the cell just as in Mccistorhinus triptcrus (Figs. 55 and 57). In Mccistorhinus sepulcralis how- ever, the first anaphase shows a definitely greater tendency for other chromosomes to follow the first large autosome out of the aggregate. Although the second large atitosome is included as rarely in the smaller second spermatocyte as in the prec
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. HARLEQUIN LOBE OF DISCOCEPHALINI 281 lobes. In the former the sex chromosomes at both metaphases become detached from the autosomal aggregate, which then is displaced toward the side of the cell just as in Mccistorhinus triptcrus (Figs. 55 and 57). In Mccistorhinus sepulcralis how- ever, the first anaphase shows a definitely greater tendency for other chromosomes to follow the first large autosome out of the aggregate. Although the second large atitosome is included as rarely in the smaller second spermatocyte as in the preceding species, a smaller autosome sometimes succeeds in following the first autosome into this cell (in four out of forty cells) (Fig. 56). Apparently both these autosomes. Mccistorhinus sepulcralis—Harlequin Lobe FIGURE 52. Confused stage (Feulgen). FIGURE 53. Diakinesis stage (Feulgen). FIGURE 54. Equatorial ring; X and Y associated with large autosomes (Feulgen). FIGURE 55. Metaphase I (Hematoxylin). FIGURE 56. Late anaphase I (Hematoxylin). FIGURE 57. Metaphase II—large cell (Hematoxylin). FIGURE 58. Anaphase II—small cell (Hematoxylin). retain the "sticky" condition of the earlier aggregate, for when they reach the pole the smaller joins the larger one and adheres to it in almost any position in random fashion. In the second division, both follow the X to the pole in the majority of cases (Fig. 58). But here too, as in the second division of Mecistorhinus tripterus the X and Y often show only a small size difference In perfect side views they can nearly always be distinguished, but if the cell is viewed at a slight angle it at once becomes difficult to do so. Hence, though Mecistorhinus sepulcralis also shows a definite preferential association between the X and the large autosome (as well as the smaller, if present). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and a
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
