11. It is the fibrous remnant of the notochord . 12. The chorda-mesoderm develops into the notochord . 13. When the development of the notochord is complete, the neurenteric canal normally closes. 14. As the ectoderm proliferates, the notochord is dragged into the middle of the developing embryo. 15. Sonic hedgehog is the secreted protein which mediates signaling activities of the notochord and floor plate. 16. A postembryonic vestige of the notochord is found in the nucleus pulposus of the intervertebral discs. 17. Stomochords were initially considered a variant of a primitive notochord , a defining feature of chordates. 18. He demonstrated that the notochord provides necessary signals to ensure the neural tube s ventral differentiation. 19. In the middle of the dorsal surface of the embryo is a linear structure called the notochord . 20. It had a primitive notochord , a structure that could have developed into a vertebral column later.
