Arachnid and that there may be up to 600,000 in total. Arachnid Arachnids () are a class (Arachnida) of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. Almost all adult arachnids have eight legs, although the front pair of legs in some species has converted to a sensory function, while in other species, different appendages can grow large enough to take on the appearance of extra pairs of legs. The term is derived from the Greek word ("aráchnē"), from the myth of the hubristic human weaver Arachne who was turned into a spider. Spiders are the largest order in the class,
Stinger receiving the venom. Spiders only bite, although some tarantulas have urticating hairs. Certain caterpillars also have urticating hairs. Organs that perform similar functions in non-arthropods are often referred to as "stings". These organs include the modified dermal denticle of the stingray, the venomous spurs on the hind legs of the male platypus, and the cnidocyte tentacles of the jellyfish. The term "sting" was historically often used for the fang of a snake, although this usage is uncommon today. Snakes are said, correctly, to bite, not sting. Stinger A stinger, or sting, is a sharp organ found in various animals (typically