. Cytology, with special reference to the metazoan nucleus. Cells. 14 CYTOLOGY CHAP. resting nucleus at telophase, and reappear in the following prophase in Ascaris, Salamandra and Allium respectively, as observed by different workers. The following are the principal views held regarding these three objects : (i) The telophase chromosomes undergo a process of vacuolation, by which each becomes converted into a spongy cylinder ; this becomes further decomposed into a loose spongework. The spongeworks formed. Fig. 6. Blastomere nuclei of Ascaris megalocephala, showing the evolution of a single s
. Cytology, with special reference to the metazoan nucleus. Cells. 14 CYTOLOGY CHAP. resting nucleus at telophase, and reappear in the following prophase in Ascaris, Salamandra and Allium respectively, as observed by different workers. The following are the principal views held regarding these three objects : (i) The telophase chromosomes undergo a process of vacuolation, by which each becomes converted into a spongy cylinder ; this becomes further decomposed into a loose spongework. The spongeworks formed. Fig. 6. Blastomere nuclei of Ascaris megalocephala, showing the evolution of a single spiral thread from each telophase chromosome, and its reappearance as the prophase chromosome of the following mitosis. (After Bonnevie, ,1 1908.) A, B, telophase ; C, resting nucleus ; D, prophase. by all the chromosomes become indistinguishably merged into one another, forming a " network of networks," which is the constitution of the resting nucleus. In the prophase a reverse process takes place, each chromosomal spongework becoming concentrated first into a spongy band, and then into a homogeneous thread. Division of the chromo- somes into daughter chromosomes takes place in prophase. [Van Beneden and Neyt (1887), Ascaris ; Boveri (1909), Ascaris ; Kowalski (1904), Salamandra (Fig. 7) ; Gregoire (1906), Allium (Fig. 8).] (2) The telophase metamorphosis consists essentially in the formation of long threads from the chromosomes ; the reticulum of the resting 1 For the abbreviations used in references to certain journals, see p. 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, W. E. (Wilfred Eade), 1882-1951. London, Macmillan and Co. , limited
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