GASTROTROCHA
Gas*trot"ro*cha, n. Etym: [NL., fr. Gr. (Zoöl.)
Defn: A form of annelid larva having cilia on the ventral side.
GASTROVASCULAR
Gas`tro*vas"cu*lar, a. Etym: [Gastro- + -vascular.] (Zoöl.)
Defn: Having the structure, or performing the functions, both of digestive and circulatory organs; as, the gastrovascular cavity of coelenterates.
GASTRULA
Gas"tru*la, n.; pl. Gastrulæ Etym: [NL., dim. fr. Gr. (Biol.)
Defn: An embryonic form having its origin in the invagination or pushing in of the wall of the planula or blastula (the blastosphere) on one side, thus giving rise to a double-walled sac, with one opening or mouth (the blastopore) which leads into the cavity (the archenteron) lined by the inner wall (the hypoblast). See Illust. under Invagination. In a more general sense, an ideal stage in embryonic development. See Gastræa. — a.
Defn: Of or pertaining to a gastrula.
GASTRULATION
Gas`tru*la"tion, n. (Biol.)
Defn: The process of invagination, in embryonic development, by which a gastrula is formed.
GASTRURA
Gas*tru"ra, n. pl. Etym: [NL., fr. Gr. (Zoöl.)