Image of Mesostephanus appendiculatus; a. Drawing of cercaria structure b. Cercaria stained with 0.5% neutral red c. Sporocyst stained with 0.5% neutral red d.–g. Images of Scanning Electronmicroscope Abbreviations: os – oral sucker, p – pharynx, in – intestine, vs – ventral sucker, eb – excretory bladder, ta – tail, fu – furca, ff – furcal finfold b – body, sp – spine, ex – excretory pore, spo – sporocyst, c – cercaria (scale a, b = 100 µm, c = 20 µm).