. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FIGURE 3. Polytroch larva of Pneumoderma atlanticum, swimming normally (arrow) in A, contracted with arrested cilia following brief contact with a probe (B) and more strongly contacted (C). Electrical record in C shows ciliary arrest potentials recorded extracellularly from a ciliated band. Size scale equals 100/t; time scale, 1 sec. response: the curling aborally of the velar margin and preoral band. This brings the postoral band into view at the outer edge (left), the arrested cilia of the preoral band being seen now on th
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FIGURE 3. Polytroch larva of Pneumoderma atlanticum, swimming normally (arrow) in A, contracted with arrested cilia following brief contact with a probe (B) and more strongly contacted (C). Electrical record in C shows ciliary arrest potentials recorded extracellularly from a ciliated band. Size scale equals 100/t; time scale, 1 sec. response: the curling aborally of the velar margin and preoral band. This brings the postoral band into view at the outer edge (left), the arrested cilia of the preoral band being seen now on their right. We have observed no synchronized arrests in ciliated cells other than those of the preoral bands, which agrees with Thompson's (1959) findings in Archidoris. The cilia of the postoral bands and food groove continue normal metachronal beating when the preoral bands are arrested. Thus it is not necessary to assume, as does Richter (1973), that feeding is impossible during arrest of the locomotory cilia. Pneumoderma larvae crawl on the bottom of their dishes or swim freely in the water by means of their ciliated bands, the cilia showing laeoplectic metachronism, like those of the veligers. Figure 3A shows a young larva extended and swimming normally in the direction shown by the arrow. A touch with a glass probe (B) causes the cilia to stop beating at the end of the power stroke or to lose their metachronism, beating weakly and irregularly. Ciliary arrest may be accompanied by some degree of muscle contraction, typically a symmetrical shortening of the whole body, which causes the sides to bulge and the cilia to be partially retracted into circular furrows. In a stronger response, such as the one shown in C, the cilia would be totally arrested and retracted until only the tips showed. These. 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
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
