Mechanical Stimulation in the Sea-Anemone Calliactis parasitica

摘要: 1. A method of administering measured local mechanical stimuli is described. Experiments were done upon the anemone Calliactis parasitica. 2. Mechanical show rapid apparent adaptation--partly due to simple causes such as contracture and passive deformation tissues. 3. When conditions are standardized a stimulus sufficient intensity on column gives nervous impulse. These can be used in same way electric shocks give facilitated responses. 4. Increasing shows threshold below which no impulse generated; with further increase strength, trains increasing numbers impulses. There exists system capable graded excitation. Gradation also observed since there summation subliminal stimuli. 5. The excitable appears oriented tangentially responds stretch rather than pressure. 6. purely endodermal. ectoderm mesogloea act only an integument. 7. On histological grounds grave difficulties supposing that impulses set arise simply directly numerous sense organs. possibility noted excitation mechanically sensitive nerve-net fire off 8. sensitivity different parts animal varies greatly. In oral disk least 4000 times column. 9. combination gross morphological features bodily organization permits purposive varied Thus strong stimulation leads closure reflex, whilst weak by contact or water movements appropriate responses connected feeding rejection.