St16-7.4hpf

late neurula (7.4 hours), the neural tube closure starts to form in the posterior territories. The notochord precursor is converging and intercalating, and the embryo elongates.

Dorsal view of three-dimensional image (upper), 50% section image (middle), and longitudinal section image (lower). Dashed lines in middle indicate the position of the section. Black arrowheads indicate the anterior edge of neural tube closure. Scale bar = 50 micro m. b.p., blastopore; n.p., neural plate; epi, epidermis; en, endoderm; mu, muscle; noto, notochord, n.t., neural tube.