On the life cycle of Hemiurus levinseni Odhner, 1905 (Digenea: Hemiuridae)

Daughter sporocysts and cystophorous cercariae were found in the gastropod Cylichna alba (Heterobranchia: Cephalaspidea) from the White Sea.By evidence from the rDNA sequences (partial 28S and 5.8S+ITS2) they match sexual adults identified as Hemiurus levinseni (Digenea: Hemiuroidea: Hemiuridae).We propose an outline of H. levinseni life cycle, describe morphology of its sporocysts and cercariae, and compare the latter with cercariae of other hemiuroideans.The position of the genus Hemiurus within the Hemiuridae is also discussed based on the molecular data.