A section through somite 8.
Observe:
1. Part of the vitelline plexus in the wall of the yolk sac cavity.
2. The extraembryonic coelom lined with extraembryonic mesoblasts.
3. The coelomic cavity subdividing the lateral plate mesoderm.
4. The pronephros represented by a ridge in the intermediate mesoderm.
Keywords: cephalic edge of somite 8 (C-4), extra-embryonic coelom, extra-embryonic mesoblast, lateral plate mesoderm, left coelomic cavity, neural tube (spinal cord part), pronephric ridge (intermediate mesoderm), right umbilical vein, umbilical vesicle cavity, vitelline plexus
Source: Atlas of Human Embryos.