Subcellular organisation of Dactylosoma cf. ranarum SK secondary merozoites. A) Tangential section through a merozoite following erythrocyte invasion. Note the micropore (encircled) in its anterior region. B–C) Apical end of a secondary merozoite in mid-longitudinal (B) and superficial (C) sections. D–E) Tangentially sectioned anterior end of secondary merozoite showing the apical complex (D) and subpellicular microtubules with circular structures (encircled in E). Transmission electron microscopy. a – amylopectin granule, black arrowhead – parasite plasma membrane, black asterisk – microneme(s), c – conoid, cr – preconoidal rings, double black arrowhead – inner membrane complex, e – erythrocyte, n – nucleus, pr – polar ring(s), r – rhoptry, small black arrow – intraconoidal microtubule, small white arrow – subpellicular microtubule, white asterisk – rhoptry duct.