Question

Which one of the following organisms is correctly matched with its excretory organs ?

• A. Humans - Kidneys, sebaceous glands and tear glands
• B. Earthworm - Pharyngeal, integumentary and septal nephridia
• C. Cockroach - Malpighian tubules and enteric caeca
• D. Frog - Kidneys , skin and buccal epithelium

Answer 1

The correct option is B Earthworm - Pharyngeal, integumentary and septal nephridia

There are three types of nephridia according to their location in the body.

1. Pharyngeal nephridia: These nephridia lie in three paired tufts, one on either side of the anterior region of the alimentary canal in the segments 4th, 5th, and 6th. Each pharyngeal nephridium is about the size of a septal nephridium but it is of the closed type having no funnel or nephrostome.

2. Integumentary nephridia: In each segment of the body from 7th to the last segment, numerous nephridia are found attached inside the lining of the body wall, called Integumentary nephridia. These nephridia are small-sized, without nephrostome and without any opening into the coelom. Hence, they are called closed type of nephridia.

3. Septal nephridia: These are found situated on the inter-seg­mental septum between 15th and 16th segments to the posterior side of the body. The septal nephridia may be considered typical of all the nephridia of Pheretima. Each septal nephridium consists of nephrostome, neck, the body of nephridium and the terminal duct.

So, the correct option is 'Earthworm - Pharyngeal, integumentary and septal nephridia'.