The nautilus is a deep-water cephalopod that lives inside a coiled, pearly, gas-filled shell, the last living member of an ancient lineage that once filled the seas. Where it is eaten — chiefly in parts of the tropical Indo-Pacific such as the Philippines and Melanesia — it yields a firm, mild, faintly sweet white meat from the animal's muscular body and many small tentacles, closer in chew to squid or whelk than to fish.