Cercaria diplostomi phoxini (Faust), a furcocercaria which develops into Diplostomulum phoxini in the brain of the minnow

Abstract

1. A fork-tailed cercaria Cercaria diplostomi phoxini (Faust) has been found to develop in sporocysts in 3·9 % of Lymnaea pereger var. ovata (Drapanaud) in Fron Goch Pool near Aberystwyth.2. The cercaria is described in detail. The arrangement of spines on the body is characteristic and there is a double row of seventy-two spines on the ventral sucker. The flame cell formula is given.3. The cercaria is compared with seven closely related types.4. Infestation experiments show that Cercaria diplostomi phoxini develops into Diplostomulum phoxini in the brain of the minnow.5. The early stage of infestation of the brain of the minnow is described and compared with an infestation of long standing.