Two Slow Conduction Systems in the Sea Anemone Calliactis Parasitica

Abstract

Suction electrodes record electrical activity associated with three conduction systems in the sea anemone Calliactis parasitica. The two slow systems (SS1 and SS2) are previously undescribed. The third system is the through-conduction system. Evidence is given that the SS1 and SS2 are located in the ectoderm and endoderm respectively. The conductile elements have not been identified. The conduction velocity of the SS1 is 4·4–14·6 cm./sec. at n° C. and is highest in the oral disk. The SS2 velocity is 3·0–5·3 cm./sec. Both slow systems show a marked increase in response delay on repetitive stimulation and fail at stimulation frequencies higher than one shock/3 sec.