The mechanisms by which the eggs of the Antarctic notothenioid fishes avoid freezing are not fully understood. Zona pellucida proteins (ZPs) are constituents of the chorion which forms a ...

In “Infinite Life: The Revolutionary Story of Eggs, Evolution, and Life on Earth,” Mr. Howard makes a case for eggs so over ...

Allantois expands very rapidly to fuse with chorion and develop blood vessels on surface which connect to umbilical cord function in gas exchange for the embryo. It’s also a respiratory organ for the ...

Obviously since eggs squeak before they hatch, ... These membranes are the chorion and the allantois. Membranes inside the egg move oxygen inside for the embryo, and pass carbon dioxide out.

At some point, there was a new sort of egg, this time with three more membranes within it: chorion, amnion, and allantois, which began to evolve.