Characters: Polyps are flat, circular or irregular in outline. There is little or no central dome. The central fossa is deep. Septa are thick, tightly packed and even, giving the oral disc a smooth appearance. Long and short septa clearly alternate. Costae are fine and only developed towards the polyp perimeter. Polyps may form more than one mouth and reproduce by autotomy, but this is rare.
Colour: Pale brown.
Similar species: Large Cycloseris hexagonalis are similar if the hexagonal pattern is not discernible. Septa are similar to those of Diaseris distorta.
