THE SWIMMING RESPONSE OF THE SEA ANEMONE STOMPHIA COCCINEA TO ELECTRICAL STIMULATION.

1. The swimming response of Stomphia coccinea evoked by electrical stimuli has been re-examined. 2. Contrary to earlier accounts, definite relationships have been discovered between the occurrence of swimming and the number, frequency and intensity of electrical stimuli applied. At higher frequencies (1 stimulus/0.4 sec), 4-6 stimuli cause swimming; at lower frequencies (1 stimulus/3.0 sec), 24-40 stimuli are needed to produce the same effect. 3. Stronger stimuli are required to evoke the swimming response than to cause the retraction response. At constant durations, the threshold for swimming is at least 50% above the voltage required for retraction; at constant voltage, the threshold duration of pulses that give swimming is at least three times the duration of pulses that cause retraction. 4. It is concluded that retraction and swimming are controlled by different excitation systems. The system controlling swimming has a higher threshold and it is not an all-or-nothing process. 5. The results are discussed in relation to facilitation of the swimming response and some behaviour patterns in another sea anemone, Calliactis parasitica .

[1]  J. Ward.  AN INVESTIGATION ON THE SWIMMING REACTION OF THE ANEMONE STOMPHIA COCCINEA. I. PARTIAL ISOLATION OF A REACTING SUBSTANCE FROM THE ASTEROID DERMASTERIAS IMBRICATA. , 1965, The Journal of experimental zoology.

[2]  E. A. Robson.  The Nerve-Net of a Swimming Anemone, Stotnphia Coccinea , 1963 .

[3]  D. Ross,et al.  The association between the hermit crab Dardanus arrosor (Herbst) and the sea anemone Calliactis parasitica (Couch) , 1961, Proceedings of the Royal Society of London. Series B. Biological Sciences.

[4]  D. Ross,et al.  The response of the sea anemone Calliactis parasitica to shells of the hermit crab Pagurus bernhardus , 1961, Proceedings of the Royal Society of London. Series B. Biological Sciences.

[5]  E. A. Robson.  The Swimming Response and Its Pacemaker System in the Anemone Stomphia Coccinea , 1961 .

[6]  E. Robson.  Some Observation on the Swimming Behaviour of the Anemone Stomphia Coccinea , 1961 .

[7]  D. Ross.  The Effects of Ions and Drugs on Neuromuscular Preparations of Sea Anemones I. On Preparations of the Column of Calliactis and Metridium , 1960 .

[8]  D. W. Ewer.  Inhibition and Rhythmic Activity of the Circular Muscles of Calliactis Parasitica (Couch) , 1960 .

[9]  G. Hoyle.  Neuromuscular Activity in the Swimming Sea Anemone, Stomphia Coccinea (Müller) , 1960 .

[10]  Donald M. Wilson.  Long-Term Facilitation in a Swimming Sea Anemone , 1959 .

[11]  P. Sund.  A Study of the Muscular Anatomy and Swimming Behaviour of the Sea Anemone, Stomphia coccinea , 1958 .

[12]  D. Ross.  Quick and Slow Contractions in the Isolated Sphincter of the Sea Anemone, Calliactis Parasitica , 1957 .

[13]  C. S. Yentsch,et al.  "Swimming" Anemone from Puget Sound. , 1955, Science.

[14]  C. Pantin,et al.  Slow Contraction and its Relation to Spontaneous Activity in the Sea-Anemone Metridium Senile (L.) , 1954 .

[15]  A. Totton.  The British Sea Anemones , 1935, Nature.

[16]  C. Pantin.  The Nerve Net of the Actinozoa , 1935 .

[17]  C. Pantin,et al.  The Nerve Net of the Actinozoa: V. Temperature and Facilitation in Metridium senile , 1937 .