So it produces some of the blood that the fetus actually contains. Now, the final extra embryonic membrane is the lantoise. So in non humans, this is a very important structure and it grows relatively large because what it does is it serves in waste disposal. So in nonhumans, in reptiles and in birds, the lantoid stores nitrogen containing byproducts within that structure and eventually following birth, that alantoise is actually discarded. Now, in humans, the lamp toys is a small outgrowth of developing the gestep tract. And what it does is it basically helps create the blood vessels that line along that umbilical cord.