Classification:

• Phylum: Chordata
• Class: Amphibia
• Order: Urodela
• Genus: Siren

Comments:

1. 1. Siren is commonly known as mud-eel.
2. 2. Body is elongated eel-like, measuring about 75 cm in length and covered with small papillae.
3. 3. Head is provided with mouth, nostrils and small lidless eyes.
4. 4. Forelimbs are small with four digits (fingers) and hindlimbs are entirely absent.
5. 5. Tail has a small caudal fin.
6. 6. Three pairs of external gills and one pair of gill-slits are present.
7. 7. Teeth are absent in both the jaws. Jaws are provided with horny sheaths.
8. 8. Fertilisation is external.
9. 9. It is a permanent larval form but exhibits few adult characters also

Source:

1. Practical Zoology Vertebrates by S.S.Lal. 2. A Manual of Practical Zoology Chordates by Dr. P.S. Verma.