. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CONDUCTING SYSTEMS OF CORYMORPHA FIGURE 13. Magnesium chloride bridge experiment. Stimulus artifacts are marked by upward-pointing arrows beneath the records. The numbers beneath the arrows indicate the time (minutes) since the start of that particular portion of the experiment. See text for further details. A distal opening response is present in Corymorpha, though judging from the literature this response should have been obtained much more readily and consist- ently than it actually was. From the electrical records
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CONDUCTING SYSTEMS OF CORYMORPHA FIGURE 13. Magnesium chloride bridge experiment. Stimulus artifacts are marked by upward-pointing arrows beneath the records. The numbers beneath the arrows indicate the time (minutes) since the start of that particular portion of the experiment. See text for further details. A distal opening response is present in Corymorpha, though judging from the literature this response should have been obtained much more readily and consist- ently than it actually was. From the electrical records obtained in the present study it is impossible to say that there is a distal opening system which is clearly separable from the TPS. Much time was spent on many animals unsuccessfully trying- various methods of eliciting consistent distal opening. Fresh animals were no more responsive or consistent than those which had been in the laboratory for some time. Nothing comparable to the slow system described by Josephson (1965) in Tubularia has been observed. Neither of the experiments which might have yielded evidence for longitudinal conduction tracts in the stalk (the experiment with three electrodes arranged trans- versely across the stalk and Parker's experiment shown in Fig. 9) gave such evidence. However, these experiments certainly do not disprove the existence of such tracts since the suction electrodes used were non-focal and the tissue bridges in the repeat of Parker's experiment might have been too wide to reveal preferential conduction. Kass-Simon (1972) has found that in Hydra bridge width is critical in deter- mining whether or not there is differential conduction in the two directions; bridges less than 100 /x or 150 /x and wider showing no significant differences in conducting ability. In view of Parker's evidence for preferential conduction in Corymorpha and the fact that the bridges used in our experiments were greater than 150 // preferential longitudinal conduct
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
