30- and 40-Day Old Amniotic Vesicles.
Amniotic vesicles can be seen inside the chorioallantois. The small cotyledons are arranged in four rows. The normal total number of cotyledons is 90 to 100. The gestational age of the top conceptus is 30 days and that of the bottom conceptus 40 days.
Mogheiseh A (2013)