-Food is passed through central mouth to internal cavity in which digestion takes place.
-Range of forms from simple solitary to complex colonial types.
-Have number of features not seen in the simpler Tabulata, such as dissepiments and various columella structures in the centre of each corallite.
-All became extinct during Permo-Triassic extinction event.
-Any fossils found in Triassic strata are derived from Permian sediments.
