Conduction system in a sponge

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Science  13 Mar 1981:
Vol. 211, Issue 4487, pp. 1169-1171
DOI: 10.1126/science.7466387


The hexactinellid sponge Rhabdocalyptus dawsoni is capable of arresting its exhalant water current in response to mechanical and electrical stimuli. The arrest is coordinated by a conduction system with a precise threshold of excitability and a chronaxie of 38 milliseconds. The response is propagated throughout the sponge at a mean velocity of 0.22 centimeter per second, and conduction is unpolarized.