. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 596 ROBERT K. JOSEPHSON MATERIALS AND METHODS Tubularia were collected from the Woods Hole area. Animals were obtained from different places at different times of the year and, judging by the information provided by Miller (1969), included three species; T. crocca from the jetty at New Bedford, T. spectabilis from Woods Hole and the Cape Cod Canal, and T. larynx from the Cape Cod Canal. For the physiological parameters considered in this study, animals thought to be T. larynx and T. spectabilis were indistinguishable. T. cro
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 596 ROBERT K. JOSEPHSON MATERIALS AND METHODS Tubularia were collected from the Woods Hole area. Animals were obtained from different places at different times of the year and, judging by the information provided by Miller (1969), included three species; T. crocca from the jetty at New Bedford, T. spectabilis from Woods Hole and the Cape Cod Canal, and T. larynx from the Cape Cod Canal. For the physiological parameters considered in this study, animals thought to be T. larynx and T. spectabilis were indistinguishable. T. crocea differs from the other two in having a longer, more active proboscis, in producing generally larger DOSP's and in other particulars described below. The stimulating and recording methods are described in detail elsewhere (Josephson and Uhrich, 1969; Josephson and Rushforth, 1973). Briefly, animals were stapled to the bottom of a dish of sea water cooled to 16-18° C. A suction electrode on a gonophore or gonophore stalk was used to activate the DOS. The stimuli were 1 msec voltage pulses. Another suction electrode on the base of a distal tentacle recorded DOSP's and HP's. Recorded activity was displayed on a pen-writer or oscilloscope. RESULTS Defacilitation during repetitive DOS activation The most obvious factor affecting DOSP amplitude is preceding DOS activity; the slow component of DOSP's shows marked defacilitation (Fig. 1A; Josephson, 1965). The time course of defacilitation was examined by stimulating the DOS at a set of interstimulus intervals ranging from 2 to 300 seconds. In each trial the intervals of the set were presented in random order. Results from four ani- mals, each subjected to 20 sets of interstimulus intervals, are shown in Figure 2. In one of these animals the DOSP's reached maximum size with interstimulus B. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and app
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
