The clitellum is part of the reproductive system of some annelids, such as earthworms and leeches, and is not excretory in function:
Clitellum
Function
Secretes a viscous fluid to form a cocoon for eggs
Location
Thickened glandular and non-segmented section of the body wall near the head
Other features
Light-colored pigment, saddle-like ring in the epidermis of the worm