an Entity references as follows:
"Cytotrophoblast" is the name given to both the inner layer of the trophoblast (also called layer of Langhans) or the cells that live there. It is interior to the syncytiotrophoblast and external to the wall of the blastocyst in a developing embryo. Cytotrophoblastic cells play an important role in the implantation of an embryo in the uterus.