‖n. pl. [ NL., fr. Gr. 'a priv. + &unr_;, &unr_;, a lung. ] (Zool.) An order of holothurians in which the internal respiratory organs are wanting; -- called also Apoda or Apodes. [ 1913 Webster ]

‖n. pl. [ NL. See Tetra-, and Pneumo-. ] (Zool.) 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. [ 1913 Webster ]