| In Deuterostomia (= second mouth) the mouth develops from the second opening into the embryonic gut. The first opening (the blastopore) develops into the anus. The body cavity (coelom) develops from buds off the gut. The group of anaimals belonging to the Deuterostomia are the vertebrates, the starfishes and sea urchins (Echinodermata), the arrowworms (Chaetognatha) and the lamp shells (Brachiopoda). |
