Clitellum is a girdle-like thick band of glandular tissue, which completely and permanently surrounds the segments 14 to 16 . Clitellum secretes mucus, albumen and an egg case or cocoon for eggs. Respiration in Pheretima takes place by diffusion of gases through general body surface. Intake of O2 and giving out of CO2 takes place between blood capillaries of outer epidermis and surface film of mucus. The haemoglobin (dissolved in plasma) acts as respiratory pigment.