[Variations in the number of metacercariae in the daughter sporocysts of Microphallus pygmaeus (Trematoda: Microphallidae)].

The daughter sporocystes of Microphallus pygmaeus from the snails of Littorina saxatilis and L. obtusata were investigated. The average quantity of metacercariae in sporocysts is influenced by host species, its syze and by the season. There are differences in the average number of larvae from parthenites of L. saxatilis, collected in the Barents and White seas.