Expansion and Contraction of the Oral Disc in the Sea Anemone Tealia Felina

Electrical stimulation of the SS 1 of Tealia felina causes inhibition of spontaneous activity and increase in length of oral disc radial muscle preparations. This response is elicited over a wide stimulus frequency range (1 every 2 sec to 1 every 30 sec). The response shows a slow onset and a long recovery period. Stimulation of the nerve net at frequencies between 1 shock every 5 sec and 1 shock every 20 sec produces slow contraction. The radials also show fast contractions to shocks less than 2 sec apart. Dissolved food substances excite the SS 1 in the column. The sensory response to application of food extract to a small area of the column shows evidence of sensory adaptation. These observations are related to the pre-feeding response of Tealia and a model for oral disc expansion is described.