[Muscular system of the Microphallus pygmaeus metacercaria (Trematoda: microphallidae)].

The musculature of body wall, attachment organs (oral and ventral suckers), and internal organs (alimentary tract, excretory bladder, and ducts of reproductive system) of the Microphallus pygmaeus metacercaria are described. An unusual arrangement of longitude and diagonal muscles was found in the hind part of the metacercaria body. Longitude fibers of dorsal and lateral body surfaces are bow-shaped and bend round the excretory pore along its ventral margin. An additional group of diagonal fibers is situated in the hind part of ventral body surface.