extraembryonic membrane

https://doi.org/10.1351/goldbook.10700

One of the membranes that surrounds the embryo, which include the yolk sac, allantois, amnion, and chorion.

Source:
PAC, 2016, 88, 713. (Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)) on page 753 [Terms] [Paper]