The coxal gland is a gland found in some arthropods, for collecting and excreting urine. They are found in all arachnids (with the exception of some Acari), and in other chelicerates, such as horseshoe crabs.[1] The coxal gland is thought to be homologous with the antennal gland of crustaceans.[2] The gland comprises an end sac (saccule), a long duct (labyrinth) and a terminal bladder (reservoir).[2] There is generally only one pair (two in some spiders), and they open on the coxae of the walking legs.[1]