SOME EFFECTS OF COVERING THE PERISARC UPON TUBULARIAN REGENERATION

¹ Marine Biological Laboratory, Woods Hole, Mt. Desert Island Biological Laboratory and University of Michigan, Ann Arbor

1. Pieces of Tubularia stems were placed in glass tubes with outside and inside diameters of 2.5 mm. and 1 mm. respectively in order to determine the rôle in regeneration played by metabolic exchange through the perisarc.

2. Using tubes of the same length it was found that when the distal ends of the stems projected less than 5 mm. from the tubes regeneration was decreased at the distal surface. When the proximal ends projected less than 5 mm. from the tubes there was an increase in distal regeneration.

3. Using tubes of different lengths (with at least 5 mm. of stem projecting from either end) slight decreases in length of the regenerate were observed with increasing length of the tubes.

4. It was concluded that the powerful effects observed when the distal ends of the stems projected less than 5 mm. from the tubes represent the limitation of diffusion of inhibitors out of as well as of oxygen into the stems. On the other hand, in the light of other experiments, it was suggested that the effects obtained by covering the middle of the stems represent the extent to which inhibitors of regeneration are eliminated through the unbroken perisarc rather than any induced alteration of the oxygen content of the coelenteron.