Clitellum

noun

1. A glandular swelling of the epidermis of certain annelid worms, such as earthworms, that secretes a viscous fluid to form a cocoon in which the eggs are deposited.
2. In zoology, the saddle of an annelid, as the earthworm; a peculiar glandular ring around the body, resulting from the swelling and other modification of certain segments.
3. A glandular swelling in the epidermis of some annelid worms; it secretes a viscous fluid in which the eggs are deposited.