Echinarachnius parma (Lamarck, 1816)
Sand dollars

Distinguishing characteristics Round, disc-like with five radial furrows branch from the mouth on the animal's underside. Size About 7-8 cm in diameter. Color Purplish brown. Habitat Sandy and muddy bottoms down to 1500 m. Feeding Deposit feeder. Grazer. Filter feeder. Life cycle The sexes are separate, with little distinction between male and female. Free-swimming larvae. Distribution Native to northern Hemisphere. Circumpolar.