Wilhelm Piela
Wilhelm Piela voted up PJ Stein's answer

There are at least five different respiratory systems in spiders, depending on taxonomic group and whom you’re talking to. 1) A single pair of booklungs, as with the cellar or daddylongleg spiders, Pholcidae. 2) Two pair of booklungs, suborder Mesothelae, and all or most of infraorder Mygalomorphae (including tarantulas). 3) A pair of booklungs and … Read more