PhaFIG 3A-D: Embryonic development of the digestive tract.

(Based on Sulston et al., 1983 and Leung et al., 1999.)
A. 200 minutes after first cell cleavage (99-cell stage), ventral aspect. (Dark green) Cells from MS lineage; (light green) cells from AB lineage.
B. 260 min after first cell cleavage (late gastrulation), ventral aspect. (Green arrow) Blastopore in which cells migrate inside the embryo.
C. End of gastrulation, dorsal aspect, midplane. Pharynx (Ph) and intestine (Int) after tubular extension.
D. 430 min after first cell cleavage, lateral aspect. Pharynx and intestine are separated from the surrounding tissues by a basement membrane. Epithelization of the buccal cavity is complete.

See also PhaFIG 3E-G.

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