dipneumones

from The Century Dictionary.

• In Haeckel's classification, a division of the Dipneusta, or Dipnoi, containing those dipnoans which are double-lunged, namely, Protopterus and Lepidosiren: distinguished from Monopneumones.
• In entomology, a division of Araneida or true spiders, having but two lungs, six spinnerets, and scattered ocelli: distinguished from Tetrapneumones. Most spiders belong to this division. Also Dipneumoneœ.