Editing Book lung (section)

{{Short description|Type of lung commonly found in arachnids}}
[[Image:Spin vent diag.jpg|thumb|right|In this spider diagram, the position of the book lungs is labelled 1.]]
[[File:Comstock-book-lungs.png|thumb|right|Spider book lungs (cross section)]]
[[File:Spider internal anatomy-en.svg|thumb|Internal anatomy of a female spider, book lungs shown in pink]]

A '''book lung''' is a type of [[respiration organ]] used for atmospheric gas-exchange that is present in many [[arachnid]]s, such as [[scorpion]]s and [[spider]]s. Each of these organs is located inside an open, ventral-abdominal, air-filled cavity (atrium) and connects with its surroundings through a small opening for the purpose of [[respiration (physiology)|respiration]].