. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FIG. i. Diagram of vegetative cell FIG. 2. Fragment of cell from which showing regions of the cut for remov- the anterior end was removed. B and C, ing the anterior or posterior end and the cells formed from it by division in the dividing the cell in half. original plane. i. Removal of the Anterior End.—In this experiment the anterior end of the cell was cut off at the level indicated in Fig. i, X, thus removing from one fourth to one third of the cytoplasm. The small non-nucleated piece (Fig. i, A) anterior to the cut usual
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FIG. i. Diagram of vegetative cell FIG. 2. Fragment of cell from which showing regions of the cut for remov- the anterior end was removed. B and C, ing the anterior or posterior end and the cells formed from it by division in the dividing the cell in half. original plane. i. Removal of the Anterior End.—In this experiment the anterior end of the cell was cut off at the level indicated in Fig. i, X, thus removing from one fourth to one third of the cytoplasm. The small non-nucleated piece (Fig. i, A) anterior to the cut usually disintegrates immediately after the operation, but in a few cases it closed in, forming a spherical mass which swam about rapidly for a day and then died. Such pieces never divide or show any sign of growth. The removal of the end often produces great disturbance in the larger nucleated piece. This is probably due to the fact that the macronucleus lies so near the level of the cut, and the oral groove prevents the closure of the wound. The following table gives the results from eighty-three individuals. TABLE I. Number of Paramecia. Regeneration Fol- lowed by Normal Fission. Division in Original Plane. No Division. Monsters. Killed. 83 28 42 8 4 2 Thirty-four per cent, of the pieces developed new cilia at the cut end and grew to the normal size before dividing, but nearly fifty per cent, divided in the original plane (represented in all figures by the dotted line) forming a small irregular anterior. 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-; Redfield, Alfred Clarence, 1890-1983. Woods Hole, Mass. : Marine Biol
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