Cocoon Formation :
Cocoon in the earthworm is formed by the clitellum. The gland cells of the modified epidermis of the clitellum secrete a slimy substance after the copulation which on air contact form a girdle around the clitellum. Soon, the clitellum receives albumin protein which acts as nutrient for the developing embryo. Now, many ova are released into the girdle. It is believed that the girdle contracts to mount pressure on the oviducts which results in the release of ova.
