Phylum Mollusca, Class Cephalopoda.
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   Squids,  octopuses,  cuttlefish,  chambered  nautiluses  are  the only
   molluscs that exhibit cephalization: development of a head.
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   They  have  a  closed  circulatory  system  that  enables them to move
   quickly by jet propulsion using siphons.
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   Tentacles are used to capture prey.