Histological study of implantation in the Natal clinging bat (Miniopterus schreibersii natalensis).

In the Natal clinging bat, Miniopterus schreibersii natalensis, implantation is centric and superficial in the right uterine horn. The blastocyst implants during the bilaminar stage with the inner cell mass orientated antimesometrially. During the preimplantation period the blastocyst becomes completely enclosed by uterine mucosae with the trophoblast in close contact with the surrounding uterine epithelium. Just before implantation the trophoblast becomes bilaminar over the greater part of the embryonic hemisphere of the blastocyst. The uterine epithelium is very persistent and parts were still present mesometrially although penetration of the uterine endometrium had already occurred on the antimesometrial side.