Answer the following
(i) What is the function of nephridia?
(ii) How many types of nephridia are found in earthworm based on their location ?

Explanation

In Pheretima three types of nephridia are present.
1. Septal nephridia 2. Integumentary nephridia 3. Pharyngeal nephridia.
1. Septal nephridia : The septal nephridia are present on the intersegmental saptum.from 15 & 16 segments onwards to last and are opens into alimentary canal.
2. Integumentary nephridia : The integumentary nephridia attached to the inner body wall from the `3^(rd)` segment to the last. They open to the exterior on the body surface by nephridiopores.
3. Pharyngial nephridia : The pharyngial nephridia present three paired tufts in the segments `4^(th), 5^(th) and 6^(th).` They open into the buccal cavity and pharynx.