| These pouches eventually fill the blastocoel forming two new pouches, the coelom. |
| The outer layer of cells is called the blastoderm, and the fluid-filled cavity the blastocoel. |
| Involution occurs here, as cells divide and push other cells into the blastocoel from the top of the dorsal lip. |
| The primitive endoderm then develops at the blastocoelic surface of the ICM, and migrates out across the inner surface of the blastocoel. |
| At gastrulation, the germ plasm is located in cells in the floor of the blastocoel cavity, among the cells that give rise to the endoderm. |
| The blastocoel appears bright grey, the animal cap darker-gray and the vegetal pole black. |
