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Sipunculida (Sipuncula; peanut worms) A phylum of coelomate worms which lack body segmentation. Like Echiurida, they are cylindrical in shape, and the mouth is surrounded by small tentacles which form part of a protrusible introvert. They have a long, U-shaped gut with the anus lying on the anterior dorsal surface. The nervous system includes a brain, and sense organs are present. Males and females occur. They are exclusively marine, all are benthic, and most feed on detritus, although some are carnivores. They are first recorded in the middle Devonian.

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