Sea Serpent
the name given to gigantic animals, presumedly of serpentine form, which have been frequently described by sailors and others.
Gigantic cuttlefishes, now proved to have a veritable existence, might in many cases imitate an elongated marine form, swimming near the surface of the sea.
It is by far the most plausible theory of sea serpent existence to suppose that most. of the animals described are really giant cuttlefishes of the Loligo or squid type.
The marine snakes or hydrophidæ of the Indian ocean would also serve to personate the "great unknown" if unusually large.