. The Biological bulletin. Biology; Zoology; Marine biology. EFFECTS OF SALINITY CHANGES ON NEREIS 237 Another new point brought out by this experiment is that, although in Experiment 1 the apparent maximum increase was at 11 hours, most of the worms had probably begun to lose weight at that time. In the present experiment the worms were weighed at 2\ hours and again at 5 hours. Here the apparent maximum was reached at the first weighing in the cases of B and C and at 5 hours by D. A com- parison of all the graphs shows that not only was there a more rapid rise but there was a longer period of
. The Biological bulletin. Biology; Zoology; Marine biology. EFFECTS OF SALINITY CHANGES ON NEREIS 237 Another new point brought out by this experiment is that, although in Experiment 1 the apparent maximum increase was at 11 hours, most of the worms had probably begun to lose weight at that time. In the present experiment the worms were weighed at 2\ hours and again at 5 hours. Here the apparent maximum was reached at the first weighing in the cases of B and C and at 5 hours by D. A com- parison of all the graphs shows that not only was there a more rapid rise but there was a longer period of rise the greater the dilution. At the end of 93 hours all were returned to sea water. All the experimental animals showed a drop in weight, a very marked one in the case of D. The noteworthy point seems to be that D dropped very soon to almost the same level as the others. Although there were some individual variations from this point to the end of the experiment, about 4 days later, the weights of all remained fairly close during this 60 60 TIME- IN HOURS 100 120 140 Fig. 4. Effect of gradual dilution of the external medium. Period in each dilution is indicated by the fractions, 7/8, indicating time in 7/8 sea water. Experiment 3. Effect of Return to Dilutions after a Period in Sea Water In this case worms were placed in various dilutions as above. The results are shown in Fig. 3. The responses of these worms to the transfers to dilutions and back to sea water were similar to those in the other two experiments described above. Ninety-six hours after the return to salt water B was transferred back to 4/5 sea water and C back to 3/5 sea water. Both increased in weight. B, however, just about paralleled the control except for one weighing. C, on the other hand, increased rather rapidly to about 25 per cent (using as a basis its original weight) after 24 Please note that these images are extracted from scanned page images that may have been digitally enhanced
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