Source : Webster's Revised Unabridged Dictionary (1913)

Cephalopoda \Ceph`a*lop"o*da\, n. pl. [NL., gr. Gr. ? head +
   -poda: cf. F. c['e]phalopode.] (Zo["o]l.)
   The highest class of Mollusca.

   Note: They have, around the front of the head, a group of
         elongated muscular arms, which are usually furnished
         with prehensile suckers or hooks. The head is highly
         developed, with large, well organized eyes and ears,
         and usually with a cartilaginous brain case. The higher
         forms, as the cuttlefishes, squids, and octopi, swim
         rapidly by ejecting a jet of water from the tubular
         siphon beneath the head. They have a pair of powerful
         horny jaws shaped like a parrot's beak, and a bag of
         inklike fluid which they can eject from the siphon,
         thus clouding the water in order to escape from their
         enemies. They are divided into two orders, the
         Dibranchiata, having two gills and eight or ten
         sucker-bearing arms, and the Tetrabranchiata, with four
         gills and numerous arms without suckers. The latter are
         all extinct except the {Nautilus}. See {Octopus},
         {Squid}, {Nautilus}.

Source : WordNet®

Cephalopoda
     n : octopuses; squids; cuttlefish; pearly nautilus [syn: {class
         Cephalopoda}]