eutherian, eutherian mammal, placental, placental mammal - mammals having a placenta; all mammals except monotremes and marsupials

cetacean, cetacean mammal, blower - large aquatic carnivorous mammal with fin-like forelimbs no hind limbs, including: whales; dolphins; porpoises; narwhals

sea cow, sirenian, sirenian mammal - any of two families of large herbivorous aquatic mammals with paddle-shaped tails and flipper-like forelimbs and no hind limbs

pinnatiped, pinniped, pinniped mammal - aquatic carnivorous mammal having a streamlined body specialized for swimming with limbs modified as flippers

flipper - the flat broad limb of aquatic animals specialized for swimming