. The Biological bulletin. Biology; Zoology; Marine biology. Fig. 4. The arrows indicate the points on each side of the base of the chimney- where the electrodes were applied. Stimulation on the Flesh. On several sponges the electrodes were applied immediately behind the osculum at distances of from 4 mm. to 2 mm. from it, and the flesh stimulated for periods varying from fifteen to sixty seconds. No effects could be seen on the chimneys. There was, however, some indication of an excitation of the choanocytes. The currents were stronger and more rapid for from ten to fifteen minutes after the
. The Biological bulletin. Biology; Zoology; Marine biology. Fig. 4. The arrows indicate the points on each side of the base of the chimney- where the electrodes were applied. Stimulation on the Flesh. On several sponges the electrodes were applied immediately behind the osculum at distances of from 4 mm. to 2 mm. from it, and the flesh stimulated for periods varying from fifteen to sixty seconds. No effects could be seen on the chimneys. There was, however, some indication of an excitation of the choanocytes. The currents were stronger and more rapid for from ten to fifteen minutes after the stimulation. Although this was taken as an indication of greater activity on the part of the flagellate cells, it is possible that the stimulation caused the ostia to dilate or open wider and in this way allow a larger volume of water to pass into the sponge body. It does not seem, however, that this would account for the increased rapidity with which the currents poured out of the oscula. There was a noticeable difference in the responses of the oscula to Faradic stimulation depending on the strength of the electrical current used. From a weak stimulus,1 a very gradual contraction was followed by a more rapid relaxation, while, if 1 By a weak stimulus is meant one which could barely be detected when the electrodes were applied to the tongue, while by a mild stimulus is meant one that could be felt when the electrodes were applied to the 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 Lillie, Frank Rattray, 1870-1947; Moore, Carl Richard, 1892-; Redfield, Alfred Clarence, 1890-; Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory (Woods Hole, Mass. ). Annual report; HighWire Press. Lancaster, Pa. [etc. ] : Lancaster Press, inc. [etc. ]
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