The marine fauna and flora of the Isles of Scilly: some marine digeneans from invertebrate hosts

Six species of larval digeneans were identified from collections of Littorina saxatilis obtained from the intertidal zone in the Isles of Scilly. Species identified include Parapronocephalum symmetricum, Cercaria parvicaudata, Microphallus pygmaeus, Microphallus similis, Maritrema linguilla, and a new form Cercaria littorinae saxatilis VII. The morphology of C. littorinae saxatilis VII and the cercaria of M. linguilla are described. All specimens of Ligia oceanica obtained from the supralittoral fringe were infected with metacercarial cysts of M. linguilla. M. linguilla is found on exposed rocky shores throughout the distribution of L. saxatilis and L. oceanica in Europe.