Nassarius incrassatus

Stuart Pearce Photo is a repost with the ID added, but here is some info on the species.... Clibanarius erythropus is a species of hermit crab that lives in rockpools and sublittoral waters. It is found in the Mediterranean Sea, Black Sea and eastern Atlantic Ocean from the Azores to Brittany, and as far north as the Channel Islands. Individuals may grow up to a carapace length of 15 millimetres (0.6 in). A variety of different gastropod shells are used by C. erythropus, the most frequent being Littorina striata, Mitra, Nassarius incrassatus and Stramonita haemastoma, which collectively account for 85% of all individuals studies in the Azores; in the Mediterranean, shells of Cerithium, Alvania montagui and Pisania maculosa are most used by C. erythropus. (Wikipedia)

Ernst Andres Great Stuart...thank you ! :-)