Fig. 32

Gymnophallus sp. metacercariae, internal musculature. a: scheme illustrating the arrangement of dorsoventral muscle fibers; b: scheme illustrating the arrangement of additonal internal muscle bundles (dorsal view), bilaterally symmetrical groups are shown only on one side; c: frontal optical slice of the trunk closer to the dorsal surface; d: frontal optical slice of the trunk closer to the ventral surface. Roman numerals mark the additional internal muscle bundles. c – caecum; dvm – dorsoventral muscle fibers; eb – excretory bladder; os – oral sucker; ph – pharynx; vs – ventral sucker