Tripneustes gratilla – Lamington urchin #mari…

Tripneustes gratilla - Lamington urchin #marineexplorer

Tripneustes gratilla – Lamington urchin #marineexplorer by John Turnbull

Via Flickr:

Common names include the collector urchin (although there are many of those) and the sea lamington. They can be white, orange, purple and brown, and various combinations, although the spines are often white on a dark background