Trophoblastic epithelial cells of the girdle proliferate to form ridges, and later glands, that abut against and are flattened by the surface of the endometrium. A mucoid material secreted into the glands adheres to the endometrium and tends to hold the girdle in place. In the image to the right, the chorionic girdle (CG) can be seen encircling the upper portion of the embryo