sirenian /saɪˈriːnɪən/

• 1. 

  ADJ of, relating to, or belonging to the Sirenia, an order of aquatic herbivorous placental mammals having forelimbs modified as paddles, no hind limbs, and a horizontally flattened tail: contains only the dugong and manatees 海牛类的

• 2. 

  N any animal belonging to the order Sirenia; a sea cow 海牛类动物