Chorion
Videos
The chorion is the outermost fetal membrane around the embryo in mammals, birds and reptiles. It is also present around the embryo of other animals, like insects and molluscs.
Placenta with attached fetal membranes (ruptured at the margin at the left in the image), which consists of the chorion (outer layer) and amnion (inner layer).
Amniotic embryo. a=embryo, b=yolk, c=allantois, d=amnion, e=chorion
Fetal membranes
Videos
The fetal membranes are the four extraembryonic membranes associated with the developing embryo and fetus in humans and other mammals. They are the amnion, chorion, allantois, and yolk sac. The amnion
Fetal membranes at end of second month with chorion shown in its two subdivisions
Fetal membranes illustrated at week 3 following gastrulation