( blas-toh-por) [Gk. blastos, sprout + poros, a way, means, path] The opening of the archenteron in the gastrula that develops into the mouth in protostomes and the anus in deuterostomes.
Gr. blastos - germ, bud, shoot; L. porus - a pore or passage]. The opening between the archenteron and outside of the embryo, formed by invagination during gastrulation. In some organisms, it becomes the anus.