Contributions to the study of the comparative morphology of teeth and other relevant ichthyodorulites in living supraspecific taxa of chondrichthyan fishes. Part B: Batomorphii. No. 4: Order Torpediniformes - Family Narcinidae - Subfamily Narcininae - Genera: Benthobatis, Diplobatis, Discopyge and Narcine, Subfamily Narkinae - Genera: Bengalichthys, Crassinarke, Heteronarce, Narke, Temera, and Typhlonarke, Family Torpedinidae - Subfamily Torpedininae - Genus: Torpedo - Subfamily T. (Tetronarke) and T. (Torpedo) and Subfamily Hypninae - Genus: Hypnos. Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, Biologie, 72, 5–45