Infestation of the slugs Milax sowerbii Férussac and Agriolimax reticulatus Müller by trematode metacercariae (Brachylaemidae)

Abstract

1. The parasitization of the slugs Milax sowerbii and Agriolimax reticulatus by a brachylaemid trematode in an area in Durham, during the period 1949–53, is described. Evidence is given that M. sowerbii is a natural intermediate host of the parasite.2. Seasonal fluctuations in the incidence of infestation are described, including the fluctuations in the incidence of the four developmental stages of the metacercariae. Primary (spring) and secondary (autumnal) infestations of the molluscs are described.3. The implications of an unexplained decline in parasite density during 1953 are noted.4. A life history for the parasite, involving a small mammal as the vertebrate host, is postulated.