Priapulans: Priapulida

Physical characteristics: Priapulus caudatus is large, as long as 8 inches (200 millimeters). The body is strongly tubular and ringed. The introvert can be quite long when extended, as much as one-third the length of the trunk.

Geographic range: Priapulus caudatus (abbreviated as P. caudatus) lives in the Northern Hemisphere, from the Arctic Ocean to the Mediterranean Sea in the eastern Atlantic Ocean and to California in the eastern Pacific Ocean.

Habitat: P. caudatus lives in the sea on soft, muddy bottoms.

Diet: P. caudatus eats waste when young and is a predator of worms as an adult.

Behavior and reproduction: P. caudatus uses its fluid skeleton for movement. The introvert and forward part of the trunk act as an anchor in the mud. Once anchored, the animal pulls itself through the Priapulus caudatus eats waste when young and is a predator of worms as an adult. (Illustration by John Megahan. Reproduced by permission.) mud by contracting body wall muscles. P. caudatus has separate sexes. Eggs and sperm are released into the water, where they unite. The larvae live in the bottom mud. As the larvae grow, they shed their outer covering and gradually grow into young animals.

Priapulus caudatus and people: P. caudatus has no known importance to people.

Conservation status: P. caudatus is not considered threatened or endangered. ∎