The primitive enteron or undifferentiated digestive sac of a gastrula or other embryo See Illust under Invagination
- central cavity associated with the gastrula; becomes the intestinal or digestive cavity
- The ancient enteron or undifferentiated digestion sac of a gastrula or other embryo. See Illust. under Invagination.
An important fact to note is that the blastopore is included in this overgrowth of epiblast, so that the neural tube remains for some time in open communication with the archenteron by means of a posterior neurenteric canal.