. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 32 \V. S. SUTTON. dimension of no value whatever. Naturally these figures can make no pretensions to complete accuracy but as approximations they serve to show a uniformity in the different nuclei that cannot justly be ascribed to chance. It is worthy of note that the only case in which a chromosome does not bear approximately the same ratio as its mates to the homologous members of the other two series is chromosome h of Fig. 5 ; which being hidden for the most part behind the accessory, is at best a doubtful quantity. ^Whe
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 32 \V. S. SUTTON. dimension of no value whatever. Naturally these figures can make no pretensions to complete accuracy but as approximations they serve to show a uniformity in the different nuclei that cannot justly be ascribed to chance. It is worthy of note that the only case in which a chromosome does not bear approximately the same ratio as its mates to the homologous members of the other two series is chromosome h of Fig. 5 ; which being hidden for the most part behind the accessory, is at best a doubtful quantity. ^When the ordinary chromosomes divide in the first mitosis of the spermatocytes, the separation takes place along the line of the longitudinal split and therefore, except that the chromo- somes are joined together by pairs, differs in no respect from an ordinary spermatogonial division. The accessory chromosome, however, though showing a clearly-defined longitudinal split, does not divide but passes entire to one pole, as Sinety ! has inde- pendently observed in the Phasmidae ; and after completion of the division may be clearly seen in one only of the two daughter cells, where it is sharply contrasted with the partially disintegrated ordinary chromosomes. FIG. Fig. 9. Four ordinary chromosomes and accessory from a very late prophase of the secondary spermatocyte division. Each ordinary chromosome is made up of two limbs connected at one end. There is no longitudinal split. In the prophases of the second division the chromosomes re- appear in the same number and show the same size relation as in '• Sinety, R. de(l9Oi), '• Recherches sur la biologic et 1'Anatomic des Phasmes," La Cellule, T. 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. ); Marin
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
