Question

The coxal glands in arachnids serves as
A) Digestive glands
B) Excretory glands
C) Reproductive glands
D) Poison glands

Answer 1

Hint: It is present in arthropods at the base of certain appendages. It helps in the removal of waste products from the body of these animals. Overall it regulates the chemical composition of their body.

Complete step by step answer:
Arachnids have a pair of excretory organs consisting of maxillary, antennal, and coxal glands. They all are open at the base of particular appendages.

- Coxal gland consists of an end sac, Labyrinth ( a long duct ) , and a terminal bladder, a reservoir.
- Coxal glands are present at the base of coxae and open on the coxae of one of the legs.
- Coxal gland consists of an end sac. The end sac is present just opposite the coxal segment of the first pair of legs, where urine is collected. An end sac is actually a tubule where secretions and reabsorption take place.
- At the first and third coxal leg segments, a short exit tube is present that opens the exterior through orifices.
- The nitrogenous waste product which is excreted by the arachnoid is actually the organic compound guanine.

Additional information:
- Arachnids are carnivorous which feed on smaller arthropods.
- The digestive system of Arachnids is a tube- like structure starting with the mouth, present below the chelicerae, and goes into the pharynx.
- From the pharynx to the esophagus and then into the sucking stomach.
- Stomach consists of heavy muscles which helps in pumping the half- digested food into the midgut.
- In the midgut, a special enzyme is present to help in digesting the food. The midgut has an absorptive surface which is increased by a series of gastric caeca.
- Waste material collects in the hindgut and passes out through the anus.
So, the correct answer is, "Excretory glands".

Note:
- Arachnids belong to the class of joint legged invertebrates including insects and crustaceans.
- All arachnids have eight legs and they do not have antennae like other insects. Their body is divided into two portions, one is Cephalothorax and the other is the abdomen.