. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 314 H. BURR STEINBACH TABLE III Per cent specific activity of K42 in Dugesia after equilibration with K^ solutions of ionic com- position indicated for five hours. Concentrations in mM/Kg. Concentrations measured for solution # 1, calculated for the others. The worms in solutions 3 and 4 showed definite signs of deterioration. Medium, mM Planaria K42 Spec. Act. Na Cl K Na Cl K 1. 17 37 2. 20 39 3. 23 41 4. 31 51 ever, the increase
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 314 H. BURR STEINBACH TABLE III Per cent specific activity of K42 in Dugesia after equilibration with K^ solutions of ionic com- position indicated for five hours. Concentrations in mM/Kg. Concentrations measured for solution # 1, calculated for the others. The worms in solutions 3 and 4 showed definite signs of deterioration. Medium, mM Planaria K42 Spec. Act. Na Cl K Na Cl K 1. 17 37 2. 20 39 3. 23 41 4. 31 51 ever, the increase in influx was slight as compared to the external concentration change. Influx of Na24 into Bdclloura is complicated (Fig. 2). There appears to be an "unexchangeable" portion of Na in the worms but results are variable with respect to this phenomenon and further investigations are needed. K42 influx into Bdelloura, following the usual initial rapid phase, seems simple and uncomplicated, the tj value being about 3% of that for Dugesia. Since Bdelloura and Dugesia are similar in size and shape, 1/tj values for influx, divided by the respective external concentrations, could give a measure of relative perme- abilities. In view of the data in Table III, this procedure is questionable but emphasizes that the marine form is considerably more permeable to ions than is the fresh-water form. 100. 20 40 60 80 100 120 140 160 180 200 220 TIME-MINUTES FIGURE 2. Influx of Na24 (dots) and K42 (circles) into Bdelloura. Radioactive element added in trace amounts to normal sea water. Results plotted as in Figure 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, 1
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