1. Protopterus is commonly known as Nile lung-fish.
2. Body is elongated,cylindrical and more or less eel-like and grows to length of 2 meters. Body is divisible into head,trunk and tail.
3. Head bears mouth,nostrils and small eyes.
4. Body covered with small cycloid scales completely enclosed in the skin.
5. The paired fins are long, thin filamentous and without fin rays.
6. dorsal , caudal and fins are united.
7. Tail is principal organ of locomotion.
8. Six branchial arches and five gill-slits are covered by operculum.
9. Air bladder is double running throughout the length of the body. It is said to breath by its lungs as well as by its gills.
10. Larval gills are usually retained as vestiges throughout life is some species. Lateral line is well-developed. They found in middle portion of great african.
Source:
1. Practical Zoology Vertebrates by S.S.Lal. 2. A Manual of Practical Zoology Chordates by Dr. P.S. Verma.
