. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Oh (induction) h h h. h h h 100 urn h Figure 2. Time course of metamorphosis in Hydrcudes eleguns. Frames represent a competent larva at the moment of induction to meta- morphosis (0 h) and selected stages for the first h after induction, p: prototroch, c: collar, b: branchial lobes, it: initiation point of calcare- ous tube, ba: branchial radioles, t: calcareous tube covering the worm. Effects of Cs^. Larvae of H. elegans metamorphosed when exposed to Cs^ in seawater. This response was depe
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Oh (induction) h h h. h h h 100 urn h Figure 2. Time course of metamorphosis in Hydrcudes eleguns. Frames represent a competent larva at the moment of induction to meta- morphosis (0 h) and selected stages for the first h after induction, p: prototroch, c: collar, b: branchial lobes, it: initiation point of calcare- ous tube, ba: branchial radioles, t: calcareous tube covering the worm. Effects of Cs^. Larvae of H. elegans metamorphosed when exposed to Cs^ in seawater. This response was dependent on concentration and duration of exposure. When the larvae were continuously exposed for 24 h to different concentrations of CsCl. the maximum response occurred with 5 niM Cs* 48 h after induction (24% meta- morphosis) (Fig. 3B). Larvae exposed for 24 h to concen- trations of CsCl higher than 5 mM showed increasing signs of toxicity. In lOmM CsCl. the branchial crown began to form, but never developed further. In the 20-mjW treatment, the larvae became immobile on the bottoms of the dishes, and at concentrations of 30 mM and higher, they died. CsCl applied in pulses of 3— h produced maximal responses (49%) (Fig. 4A); increases in neither concentration nor length of exposure produced a higher percentage of metamorphosis. At 50 mM Cs*, elongated larvae were observed on the bottoms of the dishes; at higher concentrations, the larvae died (Fig. 4B). Interactions aiuoiii; inducers Metamorphosis in response to a biofilm was greater than '-)0% in both the presence and absence of excess K^, and these values were significantly higher at 48 h (P < ) than those obtained when the larvae were exposed to excess A. 1(10 o J= c o s 411 B. 100 i o j: c u o E 8S 1 1 24 h r^m r^t^ rSe A M L 10 21) 30 40 .so (,o BIO FSW Treatment (mM excess K). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration a
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