A genus of large edentulous sirenians, allied to the dugong and manatee, including but one species (Rytina Stelleri
); -- called also Steller's sea cow
. [1913 Webster
"\'b5 It is now extinct, but was formerly abundant at Bering's Island, near Bering'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."