Classification:

• Phylum: Annelida
• Class: Polychaeta
• Order: Errantia
• Genus: Nereis

Comments:

1. 1. Nereis is commonly known as ragworm or clam worm.
2. 2. Nereis is found in Burrows in sand or mud of the seashore.
3. 3. The head consists of 2 paths a roughly triangular anterior lobe, the prostomium and posterior ring like portion, the peristomium.
4. 4. Prostomium bears a pair of terminal tentacles, dorsally 2 pairs of eyes and eventually a pair of short 2 jointed palps.
5. 5. Peristomium bears four slender cylindrical tentacles on each side and a transfers aperture, the mouth on the ventral surface.
6. 6. Each segment of the body behind the peristomium bears a pair of lateral parapodia which are locomotory organs.
7. 7. Each segment of the body behind the peritoneum bears a pair of parapodia which are locomotory organs.
8. 8. The last or annual segment is without parapodia but bears a pair of appendages known as anal cirri and a terminal anus.
9. 9. At the basis of parapodia on the ventral side in each segment are the paired openings of nephridia, the nephridiopores.
10. 10. Sexes separate, gonads develop temporarily during reproductive season.

Source:

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