Earthworms don't have a specific gland dedicated to producing mucus. Instead, they have mucus-secreting cells spread throughout their epidermis, which is the outer layer of their skin.

These cells release mucus that serves various functions for the earthworm, including:

* Keeping the skin moist: Mucus helps to prevent the earthworm from drying out.

* Facilitating movement: The mucus makes the worm's skin slippery, allowing it to move through the soil more easily.

* Protecting the skin: Mucus acts as a barrier against bacteria and other harmful organisms.

* Adhering to food: The mucus helps the earthworm to hold onto food particles.

So, while there isn't a single "mucus gland", the mucus production is distributed throughout the worm's skin.