This worm is quite cylindrical in shape with a long narrow introvert (an extension of the animal), This can be extended when feeding and retracted when threatened or when not feeding. When the introvert is pulled in the worm is rather peanut shaped and brown, it can be quite rough to the touch.

Generally found under rocks on mud or sand at low tide.

This is a deposit feeding meaning that it ingests the sand or mud and digests an organic material it finds.

Sipunculans reproduce asexually and sexually, although asexual reproduction is uncommon. When they reproduce sexually they are broadcast spawners, releasing eggs and sperm into the water. In some species the fertilised eggs hatch into miniature adults, in others there is a planktonic larval stage which can last any time from a day to a month depending upon species.