The 12-day embryo with primary villi (late bilaminar blastocyst)
Stage 5
Age 12 days
Carnegie collection 7700
Hertig and Rock, 1941.
Keywords: amnion, amniotic cavity, cytotrophoblast, embryonic disc, embryonic endoderm, endometrial stroma, epiblast, extra-embryonic coelom, extra-embryonic endoblast, extra-embryonic mesoblast, fibrous coagulum, intercommunicating lacunae, maternal blood cells in trophoblast lacuna, primary villus, primary yolk sac cavity (exocoelom), syncytiotrophoblast, uterine cavity
Source: Atlas of Human Embryos.