The young are born one by one after hatching and expelling the embryonic membrane, if any, and the brood is carried about on its mother's back until the young have undergone at least one molt.
From the en.wikipedia.org
On the inner edge lies a prominent structure, the collarette, marking the junction of the embryonic pupillary membrane covering the embryonic pupil.
From the en.wikipedia.org
Arrowheads depict the embryonic-extraembryonic junction and asterisks signify Richert's membrane that was not removed.
From the nature.com
She believes the vitelline membrane also has a role in embryonic patterning, which is essentially how the embryo learns which way is up.