The Ecology of Lough Ine

Abstract

At Lough Ine (Republic of Ireland), as elsewhere, P. vulgata occupies the drier upper levels of the shore and P. aspera the wetter lower levels. P. vulgata extends over the whole intertidal range within Lough Ine but on an adjoining headland of the open coast it is found only above mid-tide level. P. aspera is confined to the sublittoral fringe within Lough Ine but extends over the whole intertidal range on the exposed headland. Diagnostic differences in the internal appearance of the shell, the marginal tentacles of the mantle, and especially of the pluricuspid teeth of the radula are confirmed. In both species the shell is more depressed and the radula length is less at lower levels. P. aspera from the sublittoral fringe within Lough Ine has an extremely depressed shell with a crenulated margin. The presence and quantity of orange pigment in the feet may depend on environmental conditions.