Cercariae of digenean family Notocotylidae are characterized by a set of morphological traits which make them easily distinguishable from any other. One of the key features is absence of ventral sucker. This affects basic ways of locomotion and attachment. To understand how these functions are fulfilledwe studied musculature arrangement in cercariae of two species by means of fluorescent-phalloidin staining and confocal microscopy.We used Cercaria Notocotylidae sp. No. 11 and 12 Deblock, 1980 from mud snails Ecrobia (=Hydrobia) ventrosa. Information on gross morphology (especially body-tail junction) and basic behavioural patterns of these cercariae is also updated. Major special features of musculature are associated with the ventral concavity: extreme development of dorsoventral muscle fibres and formation of annular arrangement of longitudinalmuscle fibres on the ventral side. Additional body-wall and internal muscle bundles in the anterior region are also specific for notocotylid cercariae and seem to pla