Nautilus

nautilus or pearly nautilus Nautilus pompilius, unique among cephalopods in retaining an external shell, is sometimes called the chambered nautilus because this shell is built up, as it grows, by the addition of one chamber after another until there may be as many as three dozen. The animal’s body is always accommodated in the last, outer, and largest chamber, and is equipped with several score of small arms. The shell contains a gas which makes it semi-buoyant, permitting the nautilus to change depth and to swim. It is not easy to catch, but Burma is one country where it is taken in quantity, perhaps because the shell, polished down to the ‘pearl’, can conveniently be carved into the shape of a peacock, the national emblem, and will then fetch a good price.