Ceratodus \Ce*rat"o*dus\, n. [NL., fr. Gr. ke`ras, ke`ratos horn + ? tooth.] (Zo["o]l.) A genus of ganoid fishes, of the order Dipnoi, first known as Mesozoic fossil fishes; but recently two living species have been discovered in Australian rivers. They have lungs so well developed that they can leave the water and breathe in air. In Australia they are called {salmon} and {baramunda}. See {Dipnoi}, and {Archipterygium}.