Morphology and chaetotaxy of

Gymnocephalous zygocercous cercariae were shed by naturally infected snail prosobranch Hydrobiidae: Bithynia tentaculata, collected in Lithuania. Their morphology is described; they are closely related to that of several species of Echinochasmus, mainly displaying two subegal spiny suckers, excretory ducts with 15-20 large granulations, a double excretory vesicle, 16 flame cells and allow the generic determination as Echinochasmus sp. The chaetotaxy is completely carried out and shows a peculiar disposition in CII, CIV, S and U levels; in CII, CIV5 and S levels the sensillae reveal a relationship with Psilostomidae, in U level, the sensillae are different. Echinochasmus genus seems to belong to a valid family Echinochasmidae, as proposed by Sudarikov and Karmanova (1977). This family appears more closely related to Psilostomidae than to Echinostomatidae

Cathaemasia Hians (Digenea, Cathaemasiidae) from Planorbis Planorbis (Mollusca, Gastropoda) in Reservoirs of Central Polissya

The paper presents the description of Cathaemasia hians Rudolphi, 1809 trematode found on the territory of Ukraine in an intermediate host, fresh-water molluscs Planorbis planorbis. We present also a comparison of metrical characters of the studied C. hians cercariae and those described by other researchers.В статье приведены описания редий и церкарий трематоды Cathaemasia hians (Rudolphi, 1809), обнаруженных в Центральном Полесье у пресноводных моллюсков Planorbis planorbis (Linnaeus, 1758). Представлено сравнение размерных признаков обнаруженных нами личинок C. hians с церкариями этого же вида, описанными другими исследователями