\Ryt"i*na\, n. [NL., fr. Gr. "ryti`s a wrinkle.]
(Zo["o]l.)
A genus of large edentulous sirenians, allied to the dugong
and manatee, including but one species ({R. Stelleri}); --
called also {Steller's sea cow}. [Written also {Rhytina}.]
Note: It is now extinct, but was formerly abundant at
      Behring's Island, near Behring's Straits. It was
      twenty-five feet or more in length, with a thick,
      blackish, naked skin. The last were killed in 1768 for
      their oil and flesh.