-Skeletal material of chitin or calcium carbonate, with usually only the calcareous form being preserved.
-Colonies are small, 5-150mm, in fan-shaped, stick-like or lobate forms.
-Soft parts are similar to those of Brachiopods.
-128 genera to 28 in the Late Permian.
-5 families with vastly reduced diversity survived through to Triassic, but became extinct quickly.
