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Marine Animal Encyclopedia

Acorn Worm Glossobalanus sarniensis

The soft, slimy body of this wormlike animal is divided into three regions. At the acorn worm's front end is a pointed proboscis, separated from the long, thin trunk by a tubelike collar. It lives in a U-shaped burrow and feeds by trapping small organisms in sticky mucus and eating sediment. The acorn worm's sexes are separate, and reproduction can be either asexual, by fragmentation or budding, or sexual. Some biologists group acorn worms with pterobranch worms in one phylum, the Hemichordata. Unusually for invertebrates, they have some vertebrate characteristics, which include a nerve cord that runs along the back.

  • Phylum Enteropneusta
  • Size Not recorded
  • Depth Shallow water
  • Habitat Soft sediments
  • Distribution Coastal temperate waters of northeastern Atlantic