You might be thinking of calciferous glands in insects. These are glands located in the midgut of some insects, such as the silkworm moth. They play a role in:

* Calcium regulation: They help regulate calcium levels in the insect's body by absorbing excess calcium from the food and excreting it as calcium carbonate.

* Neutralizing acidic food: The secretions of calciferous glands can help neutralize acidic food, protecting the insect's digestive system.

Earthworms, on the other hand, have a simpler digestive system. They have a specialized structure called the calciferous gizzard, which helps grind up food. This gizzard is located right after the esophagus and before the intestine.

Let me know if you have any other questions about earthworm anatomy or physiology!