Studies on Larval Trematodes Infecting Freshwater Snails in London (U.K.) and Some Adjoining Areas:Part I.—Echinostome Gercariae

Abstract

Seven species of Echinostome cercariae are recorded from London ponds and rivers. Two of these, C. Z. Rees and C. echinoparyphii recurvati Mathias have already been described from other parts of Britain. The rest are new species. C. londonensis n.sp., C. deficipinnatum n.sp. are thirty-seven spined and C. essexensis n.sp. has forty-nine spines. C. hamptonensis n. sp., and C. thamesensis n. sp. are both large-tailed Echinostome cercariae, with twenty collar spines. The possibility of using snails as second intermediate hosts by C. hamptonensis , a large-tailed Echinostome cercaria is shown to be highly improbable. The classification of Echinostome cercariae is discussed.