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From Embryology
- Described in detail and illustrated by Heuser, Rock, and Hertig (1945).
- Hysterectomy Posterior wall of uterus. “The primitive villi are short and stubby; a few reach a length of about 0.25 mm.”
- Chorion, 2.6 x 1.9 x 1.4 mm. Chorionic cavity, 1.3 x 1.1 x 0.8 mm. Embryonic disc, 0.04 x 0.22 x 0.253 mm.
- Primitive streak, 0.04 mm. “Axial differentiation is just appearing.”
- “In this embryo the site of the future [cloacal] membrane seems indicated, but not the structure itself.”
- Probably no allantoic duct.
- Presumed age, 13-13.5 days. Median projection published (ibid., plate 3).
