\Sea" ser`pent\
1. (Zo["o]l.) Any marine snake. See {Sea snake}.
2. (Zo["o]l.) A large marine animal of unknown nature, often
   reported to have been seen at sea, but never yet captured.
Note: Many accounts of sea serpents are imaginary or
      fictitious; others are greatly exaggerated and
      distorted by incompetent observers; but a number have
      been given by competent and trustworthy persons, which
      indicate that several diverse animals have been called
      sea serpents. Among these are, apparently, several
      large snakelike fishes, as the oar fish, or ribbon fish
      ({Regalecus}), and huge conger eels. Other accounts
      probably refer to the giant squids ({Architeuthis}).
      Some of the best accounts seem to describe a marine
      saurian, like the fossil Mosasauri, which were large
      serpentlike creatures with paddles.