Day 45 Conceptus.

Day 45 Conceptus.
The embryo proper is surrounded by the amniotic vesicle (4.5 cm) which in turn is enclosed in the allantois. Cotyledons are developing on the external surface of the allantoic membranes. They tend to be largest near the amnion where the blood supply is the most developed. [5 cm squares]

Chenoweth PJ (2012)