Lugworms (Arenicola marina) are a species of worms in the phylum Annelida in the order of Polychaetes. They are found buried in sand dunes on almost any beach. They are abundant and convenient because if fishermen run out of bait, they can just dig into the sand and use some lugworms. They are often confused with the ragworm because their physical features are very similar. They have a segmented body. A lugworm's most common niche is burrowing its offspring into sand dunes to ensure the continuation of the species. They have cilia along their epidermis that allow them to move around and two layers of rigid muscle for protection. They are not hermaphroditic and have only one reproductive organ. The head is hooked and does not have tentacles unlike the middle of the body.