Question

How many types of nephridia are there?

Answer 1

Nephridia:

1. Nephridia are the excretory organs of earthworms which are segmentally arranged.
2. They perform excretion and osmoregulation in the earthworm.
3. There are three types of nephridia present in earthworms:
   1. Septal nephridia - They are present on both sides of the intersegmental septa of segment 15 to the last segment. They open into the intestine.
   2. Integumentary nephridia - They are attached to the lining of the body wall of segment 3 to the last segment and open into the pharynx.
   3. Pharyngeal nephridia - Three pairs of pharyngeal nephridia are present as extremely minute structures in the 4^th, 5^th and 6^th segments.