02 February 1996
Vol 271, Issue 5249

About The Cover

Living in caves and under coral overhangs on coral reefs, the polyps of the ahermatypic coral Tubastrea sp. expand at night (up to 20 to 30 millimeters in diameter) to capture planktonic prey with tentacles armed with batteries of stinging cells. Unlike their hermatypic or reef-building relatives, they do not contain symbiotic algae. See 637 and the related Report (640) and News story (597a). [Photo: A. T. Marshall, at Heron Island Reef, Australia]