Archive image from page 35 of Cytology, with special reference to. Cytology, with special reference to the metazoan nucleus cytologywithspec00agar_0 Year: 1920 20 CYTOLOGY CHAP. coarser structure may contain larger chromatin masses which would not receive that title. No general rule can be given as to the relation of the karyosomes of the resting nucleus to the telophase or prophase chromosomes. In some cases they are portions of the chromosomes which have failed to undergo the telophase dissolution and remain as compact chromatin blocks. This is well seen in Fig. 9 (Lepidosiren). Here the a
Archive image from page 35 of Cytology, with special reference to. Cytology, with special reference to the metazoan nucleus cytologywithspec00agar_0 Year: 1920 20 CYTOLOGY CHAP. coarser structure may contain larger chromatin masses which would not receive that title. No general rule can be given as to the relation of the karyosomes of the resting nucleus to the telophase or prophase chromosomes. In some cases they are portions of the chromosomes which have failed to undergo the telophase dissolution and remain as compact chromatin blocks. This is well seen in Fig. 9 (Lepidosiren). Here the anaphase chromosomes found to be constant, and to be the same as the number of chromo- somes in the species in question, as shown by Rosenberg (1904). More- over, these karyosomes may act as centres of formation for the chromosomes in prophase, for which reason they have received the name of prochromosomes (Overton, 1906). They have been specially studied in plant cells (Fig. 10). The presence of ' prochromosomes ' in the resting nucleus has been taken, with some justice, as additional evidence of the continuity of the chromosomes from one mitosis to another. It must be remembered, form a dense ring (daughter plate), the apices of the V-shaped chromosomes being on the inner circumference of the ring, while the limbs radiate outwards. At the end of telophase, when the daughter nucleus has been re- constructed, a ring of karyosomes occupies the place previously occupied by the apices of the Vs. These bodies gradually get dispersed through the nucleus and disappear, so that in the middle of the resting period they are absent.
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