trivolvis obtained from the kidneys of naturally infected Rana species tadpoles. Cysts were excysted in an alkaline trypsin-bile salts medium and the percentage of excystation was compared with that from previous studies done on cysts obtained from the kidneys of snails. The percentage of excystation of E. trivolvis metacercariae from tadpole kidneys was similar to that reported for previous studies on cysts obtained from experimentally infected gastropod hosts. The possible role of tadpoles as an agent for the transmission of Echinostoma and echinostomiasis to humans is discussed.
