Primitive mollusks, including many species of chitons, have a hard, multi-plated shell on the back and a soft underside. Abundant in inter-tidal zones and easy to harvest, chitons are an important food source for many coastal cultures.
Primitive mollusks include around 1,000 species of chitons that occur worldwide and that have remained substantially unchanged for the last 500 million years. Like other mollusks, they have a soft body with no paired or jointed limb and no developed head.