Coxal nephridia are excretory organs of the Euchelicerata (spiders and sword tails), which have developed from the segmental metanephridia originally for the arthropods. Their outputs are located at the coxae (hips) of the legs, hence the name. Coxal glands occur in one or two segments of the anterior.
In the case of crustaceans, the coxal glands correspond to the antennae and maxillary glands, which open only at the corresponding points in the head region. For original antennas such as the Chilopoda and Symphyla, 2 pairs of maxillary glands are assumed, in the Dipolopoda they have been reduced to one pair. The original insects also have a pair of maxillary glands, which open at the second maxilla, called Labium. The salivary glands have probably developed from these insects. Edit source text
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