In this type of breathing, employed by modern amphibians and air-breathing fish, the mouth cavity expands and contracts like bellows to gulp air and force it into the lungs.

• 这种形态的呼吸为现生的两生类及呼吸空气的鱼类所采用，口腔先扩大后再收缩，就像咆哮般吞嚥空气、迫空气进入肺部。