Egg has several special extra-embryonic membranes ... Other extra-embryonic folds expand up over the embryo to form the amniotic folds. The amnion and chorion develop together as upwardly projecting ...

Eggs have an evolutionary depth to them that ... beyond the better-known amnion—allantois, yolk sac and chorion—all crucial evolutionary developments that not only encompass the developing ...

serpentina (Wiedemann) eggs are described by scanning electron microscopy. A. sororcula eggs present a conspicuous sculpturing of the chorion at the micropylar end while the eggs of A. serpentina are ...

In its early life, the placenta is called a chorion because it is formed from the chorionic villi - finger-like growths which develop on the fertilised egg to help it implant in the wall of the ...

And sometimes, nature resists. The egg cells of cephalopods, for instance, have a tough, protective coating called a chorion, ...