Aspect: Generally a hard (not "spongy") dark grey or black ball with irregular outer surface and openings at its top (excurrents), an overall shaped that is somewhat reminiscent of a large wasp's nest. Population: Common. Notable feature: Outer surface can be as rough as a pinaple, and colour, as testified by specimens photograhed below, may also be dark red or brown. Environment: Shallow waters, attaches to a variety of structures. Behaviour: -
