title: Some observations on the redia, cercaria and metacercaria of Opisthodiscus nigrivasis (v. Mehlij, 1929) Odening, 1959 (Trematoda: Paramphistomidae).
mesh_terms: D000818:Animals; D005618:Fresh Water; D008124:Locomotion; D011898:Ranidae / Q000469:parasitology; D012007:Rectum / Q000469:parasitology; D012621:Seasons; D012908:Snails / Q000469:parasitology; D014200:Trematoda / Q000033:anatomy & histology / Q000254:growth & development* / Q000502:physiology