. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 338 RALPH I. SMITH using N. diversicolor at Turku. Groups of worms were adapted to dilutions of sea water of chlorosities 1, 5, 10, 15 and g. Cl/L. prior to the standard one- hour exposure in distilled water. In Figure 2 are plotted the percentages of swelling as a function of the adaptational chlorosities. As expected, worms with the higher salt gradient swelled more. Note that worms adapted to 1 and 5 g. Cl/L. behaved in this respect rather similarly; these chlorosities lie in the "regu- latory range," so th
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 338 RALPH I. SMITH using N. diversicolor at Turku. Groups of worms were adapted to dilutions of sea water of chlorosities 1, 5, 10, 15 and g. Cl/L. prior to the standard one- hour exposure in distilled water. In Figure 2 are plotted the percentages of swelling as a function of the adaptational chlorosities. As expected, worms with the higher salt gradient swelled more. Note that worms adapted to 1 and 5 g. Cl/L. behaved in this respect rather similarly; these chlorosities lie in the "regu- latory range," so that the internal concentrations are much the same. The worms adapted at 1 g. Cl/L. even showed a decrease in volume when placed in distilled water. This effect has often been noted, and probably reflects an increase in urinary output caused by increased activity and muscular tension, as postulated by 160 Adoptational chlorosily in g/L 10 15 .006. 100 200 300 400 Millimolanty, as equivalent NoCI (by conductivity) 500 FIGURE 2. Relationship between the percentage of swelling (left-hand ordinate), the amount of salt loss per 100 mg., from curves in Figure 3 (right-hand ordinate), and the chlorosity and approximate millimolarity (equivalent NaCl) of the media to which N. divcrsi- color were adapted prior to one-hour exposure to de-ionized water. Beadle (1937) in relation to volume control. Likewise, in Figures 2 and 3 it may be noted that salt loss in the worms adapted to 1 and 5 g. Cl/L. is almost identical, suggesting that the amount of salt lost in these experiments is a function of the gradient existing between interior and the medium. However, the "b" values of the set of curves in Figure 3 lend no support to the idea that the high "b" values for N. succinea could have been a result of excessive swelling. Rather, they suggest that volume increase merely depresses the surface/volume ratio. The low "b" values of and seen in the worms f
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