单词breathing bag
un.: 呼吸袋网络: 氧气囊；呼吸背囊；产包
呼吸袋
There is a breathing bag in each of the four legs and the hole of the breathing bag in hind legs is under the tail.
因为藏羚羊的四肢上部各有一个气囊，后肢气囊的窍口就在尾部。