The aboral (upper) surface is rough, being covered with longitudinally arranged, knob-shaped spines.

These are surrounded by small pedicellariae (claw-shaped structures) and interspersed by papulae (respiratory projections).

The oral (under) surface of the arms has four longitudinal rows of tube feet with suckers.

The colour of this starfish may be pale purple, pink, or green, with pale-coloured tips to the arms.

It occurs on the lower shore, where it hides under stones, and to depths of at least 200 m (656 ft).