The nautilus breathes by means of two pairs of gills; it feeds on crabs and other animals, which it catches with its long, slender tentacles (numbering more than 90) that encircle the mouth. There is a thickened area over the head, called the hood, that acts as a protective lid when the animal withdraws into the shell. The nautilus lives in deep water in the S Pacific and Indian oceans. It is active at night; during the day it stays hidden in coral crevices. It is hunted for its shell, which is used in jewelry and ornaments.
The paper nautilus, which is not a true nautilus, is a close relative of the octopus, belonging to the order Octopoda. The true nautilus is classified in the phylum Mollusca, class Cephalopoda, order Nautilida, family Nautilidae.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.
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