Effect of osmolality and selected ions on retraction of the distome body into the cercaria tail chamber of Proterometra macrostoma (Trematoda: Azygiidae).

The furcocystocercous cercariae of the digenetic trematode, Proterometra macrostoma , possess a tail chamber into which their distome body withdraws prior to emergence from their snail intermediate host. The process of distome retraction and the conditions that trigger it in this species are not clear. The objectives of the present study were (1) to describe the retraction process in P.