Published online by Cambridge University Press: 11 May 2009
Typically, adult digenetic trematodes are found as parasites of vertebrates, but Freeman & Llewellyn (1958) described sexually mature, unencysted digeneans from the kidney region of the mud-dwelling lamellibranch Scrobicularia plana (da Costa) collected from Chalkwell, near Southend-on-Sea, in the Thames estuary. The trematodes were identified as belonging to the genus Proctoeces (Odhner, 1911) and of the family Fellodistomatidae, subfamily Haplocladinae (Odhner, 1911). Freeman and Llewellyn considered that the features exhibited by the specimens were consistent with the description for Proctoeces subtenuis (Linton, 1907) Hanson, 1950, a species which had been recorded up until that date only as a parasite of the hind gut of marine teleosts belonging to the families Labridae and Sparidae from the Red Sea, New Zealand and the eastern seaboard of America.