
• (n.) A genus of large edentulous sirenians, allied to the dugong and manatee, including but one species (R. Stelleri); -- called also Steller`s sea cow.
Found on 
http://thinkexist.com/dictionary/meaning/rytina/

<zoology> A genus of large edentulous sirenians, allied to the dugong and manatee, including but one species (R. Stelleri). ... Synonym: Steller's sea cow. ... Alternative forms: Rhytina. ... 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, black...
Found on 
http://www.encyclo.co.uk/local/20973
 Ryt'i·na  noun
Ryt'i·na  noun [ New Latin , from Greek 
 'ryti`s a wrinkle.] 
 (Zoology) 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 .] » It...
Found on 
http://www.encyclo.co.uk/webster/R/108
  No exact match found.