(i) Nephridia are segmentally arranged excretory organs present in earthworms.
(ii) On the basis of their location, three types of nephridia are found in earthworms. They are:
- Septal nephridia: These are present on both sides of the inter-segmental septa behind the 15th segment. They open into the intestines.
- Integumentary nephridia: These lie attached to the body wall from the third segment to the last segment, which opens on the body surface.
- Pharyngeal nephridia: These are present as three paired tufts in fourth, fifth, and sixth segments.