aerial respirationa process of gas exchange occurring in terrestrial and some aquatic organisms, by which oxygen is absorbed from the air and carbon dioxide released. Respiratory surfaces are usually internal (e.g. the MESOPHYLL of leaves, the TRACHEAE of insects, the LUNG BOOKS of spiders and scorpions, and the LUNGS of land vertebrates), although some respiratory organs are external, e.g. the SKIN of amphibia. All surfaces rely on a water layer for gas exchange and may also depend on a blood system for transport of gases to and from distant parts of the body.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005