Green gland is the excretory organ of
prawn
butterfly
snail
earthworm
A.
prawn
In many higher crustaceans the excretory glands are located in the head. They are called antennal glands or maxillary glands, depending on whether they open at the base of the antennae or at the maxillae. If the tubule adjacent to the excretory pore is green, the gland is called a green gland.
Malphigian tubules is the excretory organ of butterflies. It is mainly to keep a constant level of salts and water in the haemolymph or blood of the butterfly. It is also to get rid of toxic compounds that are produced during metabolism.
Nephridium is the excretory organ of snails and earthworm. In Snails, it basically removes the nitrogenous waste and maintains the internal water balance. In earthworm, carbon dioxide is excreted out from the body through its moist skin by the process of diffusion.
