boof (OP) replied with this 2 months ago, 9 hours later, 12 hours after the original post[^][v]#1,402,639
and yet, I find on this page there is a paragraph that claims that the human mouth structure appears earlier, from a pre-existing gut structure. to further complicate matters, the gastrulation process specific to humans is described elsewhere as happening to a disc of cells inside the sphere of cells rather than to the sphere itself. I still haven't found a source that properly sorts out that shit. https://en.wikipedia.org/wiki/Embryological_origins_of_the_mouth_and_anus
boof (OP) triple-posted this 2 months ago, 16 minutes later, 12 hours after the original post[^][v]#1,402,642
Britannica Editors
blastopore, the opening by which the cavity of the gastrula, an embryonic stage in animal development, communicates with the exterior. During maturation of some animals it evolves into the anus or the mouth; in others it is covered over and contributes to the canal joining the primitive gut with the cavity of the neural tube, the primitive nervous system.
