The adhering to points highlight the thirteen main excretory organs uncovered in arthropods. The excretory organs are: 1. Nephridia 2. Coxal Glands 3. Environment-friendly Gland 4. Covering Glands 5. Malpighian Tubules 6. Hepatopancreas 7. Fat Body 8. Exoskeleton 9. Intestinal Caeca 10. Midgut Epithelium 11. Pericardial Cells 12. Nephrocytes 13. Oenocytes.

Excretory Organ # 1. Nephridia:

These are current in the Peripatus and are positioned on the lateral side of the segmented body cavity. Numbers of these paired organs correspond to the variety of the segments of the trunk.

Each nephridium consists of a terminal vesicle which opens up to the exterior through one end and remains connected to a coiled loop with the various other. This loop is recognized as nephridial canal and also it opens up inside the body cavity. Its inner lining is ciliated.

Excretory Organ # 2. Coxal Glands:

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These glands are existing only in Arachnida and their frameworks and also positions differ (see Table 18.18—Arthropoda). Each coxal gland is composed of convoluted tu­bules, referred to as labyrinth and a sac dubbed laby­rinth sac. It opens externally by a short tube.



Excretory Organ # 3. Eco-friendly Gland:

It is likewise known as the antennal gland also or maxillary gland also. In some species, the organs are also dubbed green gland also or antennal gland because of their colour and also place (e.g., Astacus). In some freshwater crustacean species, the organs are positioned near the maxillary segments and are referred to as maxillary glands.


It is found in Malacostraca (excepting Isopods) and also larval creates of all Crustaceans, specially in Entomostradeserve to larvae. It is current in the proximal segment of the second antenna or adjoining regions of the head. Each gland has three parts—finish sac, labyrinth and also bladder. The labyrinth is the correct excretory gland.

Excretory Organ # 4. Covering Glands:

These glands are likewise well-known as maxillary glands and also are present in the coxopodites of second maxillae in Branchiopoda, Ostracoda, Copepoda, Cirripedia and also larval forms of all Crusta­ceans.

Excretory Organ # 5. Malpighian Tubules:


These are long filamentous bodies with or without luguys and are comprised of ciliated or cubical epithe­lium. These tubules generally originate from the region of the gut which denotes the beginning of hindgut. Amongst the Crusta­ceans, the Amphipods possess one pair of tubules which originate as diverticula of the alimentary canal.

In Insecta these develop from the undistinguished region in between the midgut and also hindgut and the number varies from 2 to 150. Malpighian tubules take place in all insects other than in Collembola, some of the Thysanura and the Aphids. The tubules frequently occur in two’s or multiples of two.

The Malpighian tubules might be di­vided into 4 main types:

(a) In the most basic form the tubules join at the junction of mid­gut and hindgut. The distal ends of the tubules remain free and terminate thoughtlessly. The contents of the tubules are typically fluid and periodically uncovered the crystals once the insects are uncovered in arid problem, e.g., Orthoptera, Dermoptera and Coleoptera.

(b) In the second type the distal ends of the tubules are attached to the hindgut. The condition of these is recognized as cryptonephridial or cryptonephridic or Cryptosolenic. This condition is seen among many kind of Coleoptera and a lot of Lepidoptera. Cryptonephridial problem is seen in the insects as soon as they live in the drier environ­ments and that helps the insects to conserve water by taking in it from the faeces.

(c) The Malpighian tubules of the 3rd form remain cost-free at the distal ends and affix proximally through the gut through ampullae, and also are discovered in Hemiptera.


(d) The fourth type of Malpighian tubules are found in the Lepi­doptera and this kind is a combination of second and 3rd types. Two to 4 pairs of tubules are uncovered in Myriapods and Arach­nids and in the later the tubules are endodermal in beginning.

Excretory Organ # 6. Hepatopancreas:

In Limulus, absorp­tive cells are existing in the hepatopancreas. These cells shed large amount of calcium phosphate as excretory product right into the in­testine with which it is eliminated in addition to faeces.

Excretory Organ # 7. Fat Body:

In Insecta, Myriapoda and Onychophora, the fat bodies are comprised of polygonal cells. The cells, as they thrive old, end up being filled up with minute urate crystals.

Excretory Organ # 8. Exoskeleton:

In Crustaceans and Insects, the cells of the hypodermis secrete nitrogenous substances which remain de­posited within the exoskeleton. These are got rid of at the time of ecdysis.

Excretory Organ # 9. Intestinal Caeca:


In Squilla, the rec­tum bears a pair of intestinal caeca having actually a comb-like internal wall. These are believed to be excretory in attribute.

Excretory Organ # 10. Midgut Epithelium:

In Nauplius lar­vae of Crustacea, the cells bordering the midgut carry out excretory attribute.

Excretory Organ # 11. Pericardial Cells:

In Insects some cells approximately the heart and the pericardial mem­brane are excretory in attribute.

Excretory Organ # 12. Nephrocytes:

These are migratory cells, current in groups within the haemocoel of insects. These are pertained to as modified fat body cells and also are said to absorb undesirable colloidal pshort articles from the blood.

Excretory Organ # 13. Oenocytes:

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In Insects and also Myriapods, specific cells are found in teams approximately the abdominal spiracles. These cells originate from surface epithelium and are believed to be both excretory and circulatory in functions. The excretory system is well-arisen in land-living arthropods, which are concerned via the problem of water loss. In them the excretory organs work in such a means that very bit water is lost from the body.