Biology/Natural History: Although this is an "errant" (motile) polychaete, it builds a parchmentlike tube which has adhering pebbles, usually under boulders. This species is omnivorous, and ventures outside its tube to eat algae as well as other animals.

Reproduction in the Washington area takes place during spring and summer. During reproduction, the rear portion of the body of a number of species of Eunice breaks off as an independent, gamete-bearing individual called an epitoke which swims through the water releasing the gametes, while the anterior portion of the worm remains on the bottom. However, in this species the adults do not become anatomically specialized during reproduction. Females release yellow eggs about 1/3 mm in diameter.

Eunicids are the only polychaetes eaten regularly by humans (the Palolo worm Eunice viridis in Samoa and Fiji). The palolo worm has an epitoke which swarms during the last quarter of the moon and the lowest tides during October and November. Islanders gather the swarming epitokes for food.

This family builds only fragile parchment tubes if any.