Next we'll discuss animals from the phylum Mollusca. These animals are characterized by soft bodied, shelled animals such as clams, oysters, nudibraches, and octopi. The chiton (ky-ton) pictured above is a mollusk. Simliar to the limpet, the chiton has a broad, flat foot that it uses to hold onto the substrate. The chiton is protected by 8 overlapping calcareous plates on its back. It has a radula like a snail's that it uses to graze algae. Most feed at night and shelter under rocks and ledges by day. If they are dislodged they will curl into a tight ball to protect their vulnerable foot.