What is "gastrulae"

Gastrula \Gas"tru*la\, n.; pl. Gastrul[ae][NL., dim. fr. Gr. ? the stomach.] (Biol.) 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 Gastr[ae]a. -- a. Of or pertaining to a gastrula.

n. (plural of gastrula English)

1. n. double-walled stage of the embryo resulting from invagination of the blastula; the outer layer of cells is the ectoderm and the inner layer differentiates into the mesoderm and endoderm

2. [also: gastrulae (pl)]

See gastrula