Brittlestars have a flat, circular body (called the disc), with five or more long thin arms. The arms are jointed and flexible but break off easily, hence the name 'brittlestars'. The segments of the arms are each covered by 1-3 tiny plates, and their shape and number help distinguish species. The sides of the arms often have spines. Brittlestars move by snake - like undulation of their legs. The mouth lies on the lower surface of the body and is surrounded by five-toothed jaws. Most brittlestars have minute planktonic larvae, but a few brood their young in their bodies and give birth to minute replicas of themselves. There are 120 species in southern Africa, but only about a dozen are common.

IDENTIFICATION: The disc appears smooth to the eye and often has a net-like pattern including irregular "Y" markings near the base of each arm. The arms are pale, often white, with a narrow stripe across them about every fifth joint.

SIZE: 70 mm.

BIOLOGY: Seldom abundant; conceals its body in rock crevices and waves its arms over the rock-face.