. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 104 \V. M. SMALLWOOD. instances ova containing two nucleoli (Fig. 4) were found. The nncleolus is large and when mitosis begins has undergone a transformation similar to the changes described for Haininca (Smallwood, '05). This would indicate that the nucleolus breaks up and does not take an active part in division. Furthermore, in some cells the two centrosomes in the prophase were observed while the nucleolus was still present, the difference in size is alone sufficient to prevent confusion ; Voigt has apparently confused
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 104 \V. M. SMALLWOOD. instances ova containing two nucleoli (Fig. 4) were found. The nncleolus is large and when mitosis begins has undergone a transformation similar to the changes described for Haininca (Smallwood, '05). This would indicate that the nucleolus breaks up and does not take an active part in division. Furthermore, in some cells the two centrosomes in the prophase were observed while the nucleolus was still present, the difference in size is alone sufficient to prevent confusion ; Voigt has apparently confused them in describing the process of direct division. As the eggs mature, they are found on the surface of the ovary and can be readily distinguished by their large size as compared with the surrounding young ova. Associated with the ovary on one side only in most instances, there is found a large mass which is apparently nutritive in character (Fig. 3). An attempt was made to detect the beginning of this modification. The membrane which surrounds the ovary is continuous and passes around the nutritive mass. This structure extends from the ex- treme dorsal part of the ccelome of the seventh somite to the. FIG. i. A photograph of Branchiobdella instululin contracted. ventral body wall (Fig. 3). Several sections show this mass even passing beneath the intestine. Frequently the neural sheath of peritoneum can be shown to be continuous with the sac enclosing this mass and the eggs. All of the masses studied had a faint nucleus and in one instance a nucleolus was found which would. 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. ); Marine Biological Laboratory (Woods Hole, Mass. ). Annual report 1907/08-1952; Lillie, Frank Rattray, 1870-1947; Moore, Carl Richard, 1892-
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
