Arenicola, also known as sandworms, is a genus of capitellid annelid worms comprising the lugworms and black lugs.

The U is made of an L-shaped gallery lined with mucus, from the toe of which a vertical unlined shaft runs up to the surface.

After that the sand is kept loose by a current of water driven through the burrow from the hind end by the waves of contraction passing along the worm's body.

The larvae hatching from the eggs feed on the jelly and eventually break out when they have grown to a dozen segments and are beginning to resemble their parents.

A singing lugworm figures in The Man Who Dreamed of Faeryland by William Butler Yeats:[3] But while he passed before a plashy place, A lug-worm with its grey and muddy mouth Sang that somewhere to north or west or south There dwelt a gay, exulting, gentle race Under the golden or the silver skies Cartoonist Piers Baker created a syndicated comic strip called Ollie and Quentin, with a buddy storyline about Ollie, a seagull and Quentin, a lugworm.