gastraea
n. இரண்டு உயிரணுத்திரன் வரிசைத்தளங்களையுடைய பை போன்ற வடிவுள்ள முற்காலக் கற்பித உயிரினம்.
Gas*træ"a, n. Etym: [NL., from Gr. (Biol.) Defn: A primeval larval form; a double-walled sac from which, according to the hypothesis of Haeckel, man and all other animals, that in the first stages of their individual evolution pass through a two-layered structural stage, or gastrula form, must have descended. This idea constitutes the Gastræa theory of Haeckel. See Gastrula.