What deuterostomes from first the mouth or the anus?

Deuterostomes are a group of animals characterized by their embryonic development, where the anus forms before the mouth. This is in contrast to protostomes, where the mouth develops first. Deuterostomes include phyla such as Chordata (which encompasses vertebrates) and Echinodermata (like starfish and sea urchins). The distinction in developmental patterns is a key feature in the classification of these organisms.