| By the 20th day of gestation, the neural tube is formed and begins to close in the early stages of neurulation. |
| After neurulation, paired cavities called Hatschek's diverticula form in the head endoderm. |
| It should be regarded as a late neurulation defect taking place during fourth gestational week. |
| The gastrulation, neurulation and formation of germ layers in Branchiostoma, frog and human beings are then illustrated. |
| Alcohol exposure alters DNA methylation profiles in mouse embryos at early neurulation. |
| This sheet thickens and expands and then, in a process called neurulation, folds in on itself to form a hollow tube that pinches off from the surface of the embryo and descends below it. |
