The burrowing hermaphroditic anemone,Ceriantheopsis americanus, lives in a mucus-lined tube in sandy bottomed grass-flat areas of Tampa Bay. In this hermaphroditic species ova and sperm cysts are interspersed throughout the coupled mesenteries. The gonads occur in every other coupled mesentery beginning with the third couple. A mesentery consists of two layers of flagellated gastrodermis separated by a layer of mesoglea.