Many heterogeneously partitioned compartments. Trachea and bronchi long and supported by cartilaginous rings. Each bronchus enters lung near anterior end. Lungs even more finely divided. Lobes absent or present.
Trachea divides into right and left primary bronchi that enter lung anterior and dorsal to center.
Avian lungs and air sacs . Most of air flow not tidal, moves in one direction. Each primary bronchus enters a lung ventrally somewhat anterior to center of the organ. 7 to 10 dorsobronchi next join the primary bronchus and branch over the dorsolateral surface of lung. Ventrobronchi and dorsobronchi connected by thousands of parabronchi.