Question

Answer the following:

(i) What is the function of nephridia?

(ii) How many types of nephridia are found in earthworm based on their location?

Answer 1

(i): Nephridia : They are segmentally arranged excretory organs present in Earthworms.

(ii) On the basis of their location: There are three types of nephridia found in Earthworms.

1. Septal nephridia : They are located in four rows on the intersegmental septa in each segment behind the fifteenth segment and they are the largest nephridia.

2. Integumentary nephridia : These lie attached to the body wall from the third segment to the last segment, which opens on the body surface. They vary to 200 to 250 in each segment.

3. Pharyngeal nephridia : These are present as three paired tufts in fourth, fifth, and sixth segments, around the oesophagus. Each nephridial tuft is composed of numerous nephridia, which open into a common excretory duct.