. Cytology, with special reference to the metazoan nucleus. Cells; Cytology. 58 CYTOLOGY reaction, appearing indeed to consist now entirely of achromatin or oxychromatin. At the same time the number of nucleoU increases. At the end of the growth period the chromosomes undergo a reverse process of concentration, the filamentar outgrowths being apparently. Fig. 22. stages in the oogenesis of the dog-fish, Pristiurus. (.â \fter Mar^chal, , 1907.) A, pachytene stage, nucleolar mass already conspicuous ; B, C, passage of the diplotene stage into the germinal vesicle. In C the number of nucleoli
. Cytology, with special reference to the metazoan nucleus. Cells; Cytology. 58 CYTOLOGY reaction, appearing indeed to consist now entirely of achromatin or oxychromatin. At the same time the number of nucleoU increases. At the end of the growth period the chromosomes undergo a reverse process of concentration, the filamentar outgrowths being apparently. Fig. 22. stages in the oogenesis of the dog-fish, Pristiurus. (.â \fter Mar^chal, , 1907.) A, pachytene stage, nucleolar mass already conspicuous ; B, C, passage of the diplotene stage into the germinal vesicle. In C the number of nucleoli has increased. E), early stage in the reconstruction of the chromosomes; E, F, later stages in the condensation of the chromosomes into the definitive bivalents. These two figures are drawn at the same magnification. c, chromosome ; n, nucleolar filament. retracted on to the central axis. At the same time the staining capacity of the chromosomes increases again, and they diminish enormously in size. The nucleoU break up, and their substance shows evidence of degenerative changes, forming small granules or droplets. Sometimes these get arranged one behind the other into filaments superficially not unlike chromosomes (Fig. 22, D) but having in reality no relation to 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 Agar, Wilfred Eade, 1882-. London Macmillan
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectcells, bookyear1920
