n. plTetrapneumona(Zoöl) A division of Arachnida including those spiders which have four lungs, or pulmonary sacs. It includes the bird spiders (Mygale) and the trapdoor spiders. See Mygale.
Century Dictionary and Cyclopedia
tetrapneumonaA division of Araneina, or true spiders, having four lungs, four spinnerets, and eight approximated ocelli: distinguished from Dipneumones. It consists of the mygalids or theraphoses, the bird-spiders of South America, the tarantulas of North America, and the trap-door spiders. Also Tetrapneumones.
tetrapneumonaA group of holothurians, represented by the genus Rhopalodina, having four water-lungs (whence the name). Schmarda. Also called Decacrenidia, Diplostomidea, and Rhopalodinæ.