In which one of the following organism, its excretory organs are correctly stated?
In which one of the following organism, its excretory organs are correctly stated?
Humans - Kidneys, sebaceous glands and tear glands
Earthworm - Pharyngeal, integumentary and septal nephridia
Cockroach - Malpighian tubules and enteric caeca
Frog - Kidneys, skin and buccal epithelium
Solution
In earthworm, excretory system is made up of many segmentally arranged microscopic coiled tubes called nephridia. These are ectodermal in origin and analogous to vertebrate kidney.
In Pheretima, following three types of nephridia are seen.
(i) Pharyngeal nephridia-Situated in either side of pharynx and oesophagus in $4^{\text {th }}, 5^{\text {th }}$ and $6^{\text {th }}$ segment.
(ii) Integumentary nephridia-Scattered in the body wall, seen from $7^{\text {th }}$ segment onwards.
(iii) Septal nephridia-Largest nephridia attached to both faces of each intersegment septum behind $15^{\text {th }}$ segment.