United States or Kiribati ? Vote for the TOP Country of the Week !
Protopterus has external as well as internal gills. The paleozoic Dipneusts that are in the direct line of our ancestry, and form the connecting-bridge between the Ganoids and the Amphibia, differ in many respects from their living descendants, but agree with them in the above essential features.
The Ceratodus of certain Queensland rivers has one lung; though, I was told by the experts in Queensland, it is not a "mud-fish," and never lives in dry mud. However, the Protopterus of Africa and the Lepidosiren of South America have two lungs, as well as gills, and can live either in water or, in the dry season, on land.
Proselachii. : 16. Natidanides. Chlamydoselachius. Heptanchus. Silurian. 17. Ganoides. Plated-fishes. Proganoides. : 17. Accipenserides. Devonian. : 18. Dipneusta. Paladipneusta. : 18. Neodipneusta. Ceratodus. Protopterus. Carboniferous. : 19. Amphibia. Stegocephala. : 19. Phanerobranchia. Salamandrina. Permian. : 20. Reptilia. Proreptilia. : 20. Rhynchocephalia. Primitive lizards. Hatteria.
Executing several journeys very rapidly, it soon clears out its dwelling. The dipnoid Protopterus, which inhabits the marshes of Senegal and Gambia, is curious in more than one respect. Firstly, it can breathe oxygen, whether, like other fish, it finds it dissolved in water or in the atmospheric air.
At the period corresponding to the dry period of its own country, the Protopterus buried itself in the mud which had been placed at the bottom of the aquarium. In order to realise the conditions found in nature, the water which covered it was gradually withdrawn.
Word Of The Day