part of part of immediately preceded by immediately preceded by occurrent stage 17 early organogenesis stage mid-organogenesis stage The embryo is elongated along the animal-vegetal axis and has thus a characteristic oblong shape. The archenteron is overall deflected orally and its tip is enlarged, rounded, and smooth. The tip of the archenteron is further starting to display filopodia that interact with the ectoderm site where the mouth will form. At the tip of the archenteron, unpaired evaginations of the coelom are also now apparent, even though the stomodeal invagination, gut constrictions, and ciliary band(s) are still not discernable. Mesenchyme cells have dispersed through the blastocoel. ecao_developmental_stage