REVERSIBLE INHIBITION OF SWIMMING IN STOMOTOCA ATRA BY MESOGLEAL EXTRACTS OF SOME OTHER MEDUSAE

¹ Laboratory for Quantitative Biology, University of Miami, Coral Gables 46, Florida, and Friday Harbor Laboratory, University of Washington, Friday Harbor, Washington

1. Specimens of Stomotoca atra ceased to swim when they were placed in the same container with Aequorea aequorea medusae.

2. This inhibition of swimming was also produced by pieces of the isolated mesoglea from A. aequorea, and by mesogleal extracts from the latter.

3. Methods for preparing large amounts of a "standard" mesogleal extract of Aequorea are described.

4. The inhibitory action of the fluids was not a result of change in pH.

5. The inhibitory agent from Aequorea mesogleal fluids was heat-stable and dialyzable.

6. Larger concentrations of the inhibitory substances were found in the non-mesogleal portions of Aequorea.

7. The inhibitions were completely reversible, even after 12 hours' constant exposure to a 1/20 mesogleal extract.

8. The mesogleal extracts affected individual parts of the dissected S. atra.

9. The swimming of no other medusae tested was affected by the mesogleal extracts of Aequorea.

10. Extracts from all medusae tested, except from Stomotoca atra itself inhibited the swimming of the S. atra.