Abstract
To contribute to the phylogenetic evaluation of the river dolphin, the morphology of the tracheobronchial tree of the Ganges river dolphin was analyzed according to Nakakuki's fundamental bronchial tree model of mammals. In the right lung, the bronchial tree consists of the tracheal bronchus, five lateral series bronchi, three dorsal series bronchi and one ventral series bronchus. In the left lung, it consists of five lateral series bronchi, four dorsal series bronchi and one ventral series bronchus. In the Ganges river dolphin, the tracheal bronchus corresponds to type III of Nakakuki's nomenclature. This characteristic is of especial interest in light of the fact that the Ganges river dolphin has a forestomach as do Artiodactyla.
