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Webster 1913 Edition
Gastraea
‖
Gas-træ′a
,Noun.
[NL., from Gr. [GREEK], [GREEK], the stomach.]
(Biol.)
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
.