The life cycle of Echinoparyphium ralphaudyi sp. n. (Trematoda: Echinostomatidae).

The life cycel and morphology of Echinoparyphium ralphaudyi sp. n. is described. Natural infections were found in Bulinus truncatus from Egypt, Ethiopia, and the Yemen Arab Republic, and later in B. forskalii and B. sericinus from Ethiopia. Sporocysts develop near the places of miracidial entry into the snail (the head-foot region, mantle edge, pseudobranch, and antennae). Rediae occur mainly in the ovotestis and in tissues anterior to the liver. The first cercariae are released 24 days postexposure. Metacercariae encyst in various freshwater snails and are localized in the pericardial sac and the posterior part of the kidney. Adult worms live in the small intestine of a variety of experimental animals: hamsters, rats, mice, chicks, ducklings, pigeons, and finches.