One of the problems with early polarized sunglasses was delamination, when the polarizing film separated from the pieces of glass or plastic.
These two endoderm-rudiments embryonic membrane formed by delamination from the blastoderm, ultimately grow together and give rise to the epithelium of the midwhile in a few insects, including the wingless spring-tails, the emgut.
In the Coelentera the ectoderm and endoderm are set apart from one another at a very early period in the life-history; generally either by delamination or invagination, processes described in the article Embryology.
I, A) or by splitting off (delamination).
The hypoblast in some forms originates by invagination, in others by delamination.