Mollusca

http://upload.wikimedia.org/wikipedia/commons/1/1b/Nautilus_profile.jpg

          The phylum mollusca is formed of three classes, bivalvia, cephalapoda, and gastropoda. Mollusca contains over 85,000 species of invertebrates.
          One unique type of mollusk is the nautilus. Nautilus Pompillius is a mollusc of the class cephalapoda. Nautilus can be found in the Indo-Pacific area near the bottom, sometimes diving to 500 meters beneath the surface. Nautilus have nearly no control over which direction they move. Nautilus move backwards using a jet of water being forced out of the funnel. The only way for a nautilus to turn is to catch a rock with their numerous tentacles or to bump into a rock or wall.

http://biology.unm.edu/ccouncil/Biology_203/Images/Protostomes/Nautilus.jpg

          Nautilus reproduce sexually, reaching maturity at 15-20 years of age. They lay eggs that hatch into fully formed miniatures of the adults. They breathe using gills that extract oxygen from the water around them.  They eat fish and crabs, relying on scent to detect and hunt their prey.