(class Osteichthyes, subclass Dipneusti)
An order of lungfish with a cylindrical body, paired lungs, and nearly filamentous pectoral and pelvic fins. The larvae have tadpole-like external gills. The order includes the African (Protopteridae) and American (Lepidosirenidae) lungfish, which live only in freshwater basins.
Subjects: Zoology and Animal Sciences.