蛇颈龙
Plesiosaurus \Ple`si*o*sau"rus\, n.; pl. {Plesiosauri}. [NL., fr. Gr ? near + ? a lizard.] (Paleon.) A genus of large extinct marine reptiles, having a very long neck, a small head, and paddles for swimming. It lived in the Mesozoic age.
plesiosaurus n : extinct marine reptile with a small head on a long neck a short tail and four paddle-shaped limbs; of the Jurassic and Cretaceous [syn: {plesiosaur}]