Clam worms (Alitta succinea) are a species in the phylum Annelid and class of Nereididae. Though most Annelida species live in beaches or deserts, clam worms live on the bottom of the ocean floor. To protect themselves from predators, they use their mucus to form a shield around them. Unlike the Platyhelminthes and Nematoda, clam worms are not hermaphroditic and they only have one sex organ. Clam worms have two types of muscles, valve muscles and a foot muscle. The valve muscles allow the clam worms to live on land for short periods of time without suffocating. The foot muscle is controlled by an anterior and posterior muscle that allows the clam worm to bury itself in the sand to escape predators, find warmer waters in the winter, and find a new food source if needed.