Spider Spider Spiders (order Araneae) are air-breathing arthropods that have eight legs and chelicerae with fangs able to inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other orders of organisms. Spiders are found worldwide on every continent except for Antarctica, and have become established in nearly every habitat with the exceptions of air and sea colonization. , at least 45,700 spider species, and 113 families have been recorded by taxonomists. However, there has been dissension within the scientific community as to how all these families should be classified, as evidenced by
Pauropoda Pauropoda Pauropods are small, pale, millipede-like arthropods. Around 830 species in twelve families are found worldwide, living in soil and leaf mould. They look rather like centipedes, but are probably the sister group to millipedes. The name is derived from the Greek roots ' "few" and ' "foot". Pauropods are soft, cylindrical animals with bodies long. The first instar has three pairs of legs, but that number increases with each moult so that adult species may have nine to eleven pairs of legs. They have neither eyes nor hearts, although they do have sensory organs which can detect light. The