What is a Nautiloid?

Nautiloid is category of marine mollusk.
Nautiloids are cephalopods which includes modern creatures such as the octopus, squid and cuttlefish.
Nautiloids are characterized by a chambered shell which houses the soft parts of the animal.

Nautiloids first appeared in the fossil record in the early paleozoic era, over 500 million years ago,
however most all of the species which ever lived are now extinct.
Most early nautiloids had straight conical shells. Later species developed coiled shells.

One of the few living species of nautiloids is the chambered nautilus.
This specimen of the chambered nautilus lives at the Monterey Bay Aqarium in Monterey, California.

This specimen lives at the Shedd Aquarium in Chicago.
Click on him to see him move.