. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FIGURE 2. The levels at which worms were cut for the experiments with chick embryo extract. ultrafiltrate in 1/10 Niu-Twitty saline (Niu and Twitty, 1953) were the only levels showing bipolar head regeneration, , heads forming at each end of the cut segments of the worms. Segments of worms from regions 1 to 4 and 7 to 8 regenerated heads at the anterior end and tails at the posterior ends. No bipolar heads arose in pieces cultured in saline alone and these pieces formed heads at the anterior end surface and tails at the
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FIGURE 2. The levels at which worms were cut for the experiments with chick embryo extract. ultrafiltrate in 1/10 Niu-Twitty saline (Niu and Twitty, 1953) were the only levels showing bipolar head regeneration, , heads forming at each end of the cut segments of the worms. Segments of worms from regions 1 to 4 and 7 to 8 regenerated heads at the anterior end and tails at the posterior ends. No bipolar heads arose in pieces cultured in saline alone and these pieces formed heads at the anterior end surface and tails at the posterior end. In further experiments, twenty sections each of posterior body levels 5 and 6 from worms starved for 5, 10, 20 and 30 days were cultured in saline and nutrient media. The sections were exposed to test solutions for 4 days, after which regeneration was completed in 1/10 saline (Table I). No bipolar head regenera- tion occurred in the short posterior pieces from worms starved 5-10 days. However, 6 bipolar heads out of 26 cut pieces regenerated from cut posterior level 5 pieces and 8 bipolar heads out of 21 cut pieces were formed in posterior level 6 cut pieces in nutrient media from worms starved for 20 days. After 30 days of starvation, 9 of 34 level 5 pieces formed bipolar heads in nutrient media, while 7 of 25 level 6 pieces in nutrient media regenerated bipolar heads. None of the posterior level pieces produced bipolar heads when the medium was 1/10 Niu Twitty saline (Table I). A typical regenerate with a bipolar head is shown 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, 1870-1947; Moore, Carl Richard, 1892-; Redfield, Alfre
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
