Euphractus sexcinctus. (A) Hematoxylin and eosin. Montage of the villous area (V) above the myometrium (Myo). Magnification 10*. (B) Hematoxylin and eosin. Fetomaternal interface with spiral artery derivative (arrow). (C) Transmission electron miscroscopy. A single-layered barrier with syncytial trophoblast (Syn T) was situated between the fetal capillaries (FC) and maternal blood spaces (MS).