Anatomy of the Human Body, before 1858

Series of transverse sections through the embryonic disk of tarsius. (after hubrecht. ) section i passes through the disk, in front of hensen’s knot and shows only the ectoderm and entoderm. Sections ii, iii, and iv pass through hensen’s knot, which is seen in v tapering away into the primitive streak. In iii, iv, and v the mesoderm is seen springing from the keel-like thickening of the ectoderm, which in iii and iv is observed to be continuous into the entoderm. Object Type: "version. Date: before 1858.