n. the site of the embryonic anus, marked by a depression lined with ectoderm. The membrane separating it from the hindgut breaks down in the third month of gestation. Compare stomodeum.
n. the site of the embryonic mouth, marked by a depression lined with ectoderm from which the teeth develop. The membrane separating it from the foregut breaks down by the end of the first month of pregnancy. Compare proctodeum.... stomodeum
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