This group includes the Winkles (Littorinids) and Chink shell (Lacunids). These two groups are distinguished by the presence of a 'slit' in the column of the chink shells (hence their name). The Littorinids in particular are a very variable group which has led to a degree of controversy in their taxonomy. Have evolved to live in some of the most extreme areas of the rocky shore and are ubiquitus on almost all rocky shores around the UK. They feed by scraping up seaweed or microscopic algae using a ribbon of teeth known as a radula.