File talk:Stage8 bf6.jpg
From Embryology
Carnegie No. 5960
- Specimen described by Heuser (1932b).
- Hysterectomy. Presumed age, 18 days.
- Chorion, 15 x 14 x 9 mm.
- Embryonic disc (narrow type), 1.25 x 0.68 mm (in straight line); 1.53 x 0.75 mm (by flexible scale).
- Primitive streak, 0.5 (0.44?) mm.
- Primitive node, 0.2 (0.06?) mm, slightly caudal to midpoint of embryonic disc.
- Notochordal process, 0.42 mm (George, 1942). Notochordal canal (about 0.4 mm) opens ventrally.
- Prechordal plate, 0.15 mm. Florian (1934b), however, believed that the prechordal plate was situated further rostrally than shown by Heuser.
- Angiogenesis in umbilical vesicle, body stalk, and chorion. Angiogenesis in chorion described by Hertig (1935).
- Neural groove.
- Dorsal and median projections published (Heuser, 1932b, figs. 33 and 47; Mazanec, 1959, fig. 63).
