The canals of Lambert are accessory connections in the lungs between some bronchioles and their adjacent alveoli. Their diameter is up to 200 µm.Along with the Pores of Kohn they facilitate collateral movement of gases within the smallest parts of the lungs. However, while the Pores of Kohn connect alveoli to adjacent alveoli, the Canals of Lambert connect terminal bronchioles to alveoli.
The canals of Lambert are cladded by bronchiolar epithelium.
References
Canals of Lambert Wikipedia(Text) CC BY-SA