EXCYSTATION OF APOSTOME CILIATES IN RELATION TO MOLTING OF THEIR CRUSTACEAN HOSTS. II. EFFECT OF GLYCOGEN

¹ Rockefeller University, New York, N. Y. 10021
² The Marine Biological Laboratory, Woods Hole, Mass. 02543

To test the hypothesis that a substance or substances normally present in the blood and tissues of pre-molt crabs initiates metamorphosis and subsequent excystation of apostome phoronts, we put excised hermit crab gills bearing Hyalophysa and Gymnodinioides phoronts in sea-water-antibiotic solutions containing blood from other species of crabs or low concentrations of glycogen. As a control gills from the same crab were put into the sea-water-antibiotic mixture alone. The glycogen solutions were more effective in inducing both metamorphosis and excystation of the phoronts than the heterologous crab blood. In repeated trials, in which the controls showed no changes, metamorphosis and excystation occurred with glycogen concentrations of 0.12 to 0.5%. This was true even if the phoronts were on gills taken from a hermit crab only recently molted and hence far from its next molt.