Question

In an earthworm, pharyngeal nephridia of 6th segment open into_______

• A. Pharynx
• B. oesophagus
• C. buccal cavity
• D. exterior

Answer 1

The correct option is C buccal cavity

The excretory system of earthworm consists of coiled tubules called nephridia. There are three types of nephridia present:

1. septal nephridia: present on both the sides of the intersegmental septum of 15 to the last segment and they open into the intestine.
2. Integumentary nephridia attached to the body wall from 3rd to the last segment and they open on the body surface.
3. Pharyngeal nephridia present as three paired tufts present in 4th, 5th and 6th segments. The nephridia of 4th and 5th segments open by ducts into the pharynx in 4th segment. Pharyngeal nephridia of 6th segment open into the buccal cavity in 2nd segment.

Nephridial system in Earthworm