anal membrane

https://doi.org/10.1351/goldbook.10375

In the embryo, dorsal part of the cloacal membrane after its division of the urorectal septum.

Source:
PAC, 2016, 88, 713. (Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)) on page 721 [Terms] [Paper]