Conical shaped shell sculptured with rounded nodules arranged in spiral rows.Greenish grey or dull purple colour.

Subtidally to 20 m on semi-exposed to exposed coastlines. Most abundant in areas grazed by sea urchins.

It feeds on the microalagal films which cover the surfaces of rocks and on seaweed.

Coastal Marine inverts Vol 1. Photo Credit: Rod Morris. Photos available from www.rodmorris.co.nz