The fetal layer of the placenta on the other hand is called the chorion, which is a tissue that has fingerlike projections called chorionic villi which contain tiny fetal arterioles and venules.
But the placenta -- the organ that provides material to the embryo from the mother -- is actually formed from the chorion and allantois membranes of the egg.
Because, the main membranes of an amniotic egg -- known as the sac, the chorion, and the allantois -- are all present in animals that give birth to live young.
Her belly is pretty big, so it's harder sometimes to know those things, unless you are able to see what we call the chorion, which is the separation between the two sacs.