A Brittle Star caught in a crab trap at the Channel Islands off the coast of Santa barbara, California. .A brittle star has five unbranched or branched arms, set off from a.central disc. The arms appear to be jointed because of four.longitudinal rows of shields. There are two rows of lateral shields.with 2 to 15 spines arranged in rows. Spines vary in shape and.size depending on the species. A variety of colors is seen among.brittle stars and they are often mottled or banded.Brittle stars are the most mobile echinoderms. Flexible arms are.used for crawling or clinging. The lateral arm spines provide.traction. Brittle stars live on spiny sponges and other sessile animals in great massive fields on the muddy seafloor, as well as by themselves or in abundance directly on the seafloor. Different species of brittle stars eat in different wayssome are suspension feeders and eat food particles suspended in the water; some are deposit feeders and feed on organic particles that settle on the seafloor; and some are active predators, detecting food by its odor. There are around 2,000 species of brittle starmore than any other group of sea stars.