The purple sea urchin is an aptly named species, easily identified by the strikingly vivid, purple spines that project from its rounded body. These conspicuous spines are attached to a hard outer body wall, known as the ‘test’ (3). Also attached to the test are suckered, tentacle-like appendages, known as ‘tube feet’, which are used in locomotion, feeding and respiration (2) (3) (4). The purple sea urchin exhibits a phenomenon called ‘radial symmetry’, where the body of the sea urchin is arranged around the central axis of the mouth (2) (3) (5). As with other sea urchin species, the mouth is located underneath the body, close to the substrate. In the purple sea urchin, the mouth is part of an unusual feeding structure, commonly called ‘Aristotle’s lantern’, in which five toothed, calcareousplates are arranged to make up a powerful jaw that is well adapted to scraping at the substrate.