Argentophilic structures of the miracidium of Echinochasmus perfoliatus (Trematoda: Echinostomatidae).

Argentophilic structures of the miracidium of Echinochasmus perfoliatus were described from material collected in the vicinity of Vladivostok, Far East of Russia. Impregnated with 0.5% solution of AgNO3 miracidium showed 21 epidermal plates arranged in four rows: 6 + 9 + 4 + 2. Up to 23 papilla-like structures on the terebratorium were arranged along three axes and in four groups. A single papilla was located at the base of each of ventral and dorsal epidermal plates of the first row. Two papillae were located at the base of each of lateral epidermal plates of the first row. The eyespots were located posterior to the first row of plates. Two excretory pores were located anterior to the last row of plates. The results obtained were compared with the argentophilic structures of closely related species of the genus Echinochasmus.