A section through the roof of the rhombencephalon.
Observe:
1. The continuity between ectoderm and neural ectoderm where the rostral neuropore closed.
2. The thin-walled roof of the rhombocoele (hindbrain ventricle), which will be invaginated by blood vessels to form a choroid plexus.
Keywords: ectoderm, junction of ectoderm and neural ectoderm, mesoderm, neural ectoderm, rhombocoele (hindbrain ventricle), roof of rhombencoel (fourth ventricle)
Source: Atlas of Human Embryos.