This worm is found round the coasts of north west Europe, the Mediterranean Sea, the Gulf of Maine and Cobscook Bay.

There is a proboscis which can be extended forward from an opening above the mouth and which can be as long as the body and it is armed with a needle-like stylet.

[3] This worm is locally abundant on fairly clean sandy or gravelly sediments from just below the zone where Pelvetia canaliculata grows down to depths of 250 metres.

It is also found amongst shell debris, on Laminaria, Fucus and Ascophyllum and, less commonly, in silty or muddy areas.

Several waves may occur simultaneously and the worm glides forward slowly and smoothly, the swellings running evenly along the body.