What does "rytina" mean?

Rytina: 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.