THE OCCURRENCE AND IDENTIFICATION OF ECHINOSTOMA-REVOLUTUM FROM NORTH-AMERICAN LYMNAEA-ELODES SNAILS

Lymnaea elodes snails collected in northern Indiana, U.S.A., were infe cted with larval stages of an echinostome bearing 37 collar spines and resembling members of the Echinostoma group. The taxonomic status of this digenean was determined through experimental infections of variou s definitive and first-intermediate hosts. In addition, characteristic s of the penetration and paraesophageal glands in cercariae from this echinostomatid were compared with those from E. revolutum and E. trivo lvis. Results indicate that this recently discovered 37-collar-spined echinostome parasitizing lymnaeid snails is E. revolutum, making this the first clear report of this trematode in North America.