The Ecology of Lough Ine. XV. The Ecological Significance of Shell and Body Forms in Nucella

The gastropod Nucella lapillus (L.) is abundant between tidemarks on many rocky shores, where it feeds mainly on mussels (Mytilus edulis L.) and on barnacles. The form of the shell varies (Moore 1936); on the open coast at Carrigathorna, near Lough Ine, the shells are wider and thinner than in the Lough Ine Rapids (Ebling, Kitching, Muntz & Taylor 1964). We do not know to what extent these differences are determined by