Title: Arthropod leg
Content: of extant arthropods but modern arthropods have eight or fewer. It has been argued that the ancestral leg need not have been so complex, and that other events, such as successive loss of function of a "Hox"-gene, could result in parallel gains of leg segments. The appendages of arthropods may be either biramous or uniramous. A uniramous limb comprises a single series of segments attached end-to-end. A biramous limb, however, branches into two, and each branch consists of a series of segments attached end-to-end. The external branch (ramus) of the appendages of crustaceans is known as the exopod or exopodite,

Title: Terrestrial locomotion
Content: The most diverse group of animals on earth, the insects, are included in a larger taxon known as hexapods, most of which are hexapedal, walking and standing on six legs. Exceptions among the insects include praying mantises and water scorpions, which are quadrupeds with their front two legs modified for grasping, some butterflies such as the Lycaenidae (blues and hairstreaks) which use only four legs, and some kinds of insect larvae that may have no legs (e.g., maggots), or additional prolegs (e.g., caterpillars). Spiders and many of their relatives move on eight legs – they are octopedal. However, some creatures

Title: Terrestrial locomotion
Content: animals with the most legs are the millipedes. They have two pairs of legs per body segment, with common species having between 80 and 400 legs overall – with the rare species "Illacme plenipes" having up to 750 legs. Animals with many legs typically move them in metachronal rhythm, which gives the appearance of waves of motion travelling forwards along their rows of legs. The legs of tetrapods, the main group of terrestrial vertebrates, have internal bones, with externally attached muscles for movement, and the basic form has three key joints: the shoulder joint, the knee joint, and the ankle

Title: Terrestrial locomotion
Content: move on many more legs. Terrestrial crustaceans may have a fair number – woodlice having fourteen legs. Also, as previously mentioned, some insect larvae such as caterpillars and sawfly larvae have up to five (caterpillars) or nine (sawflies) additional fleshy prolegs in addition to the six legs normal for insects. Some species of invertebrate have even more legs, the unusual velvet worm having stubby legs under the length of its body, with around several dozen pairs of legs. Centipedes have one pair of legs per body segment, with typically around 50 legs, but some species have over 200. The terrestrial

Title: Arthropod leg
Content: the tarsus. The claws of the scorpion are not truly legs, but are pedipalps, a different kind of appendage that is also found in spiders and is specialised for predation and mating. In "Limulus", there are no metatarsi or pretarsi, leaving six segments per leg. The legs of crustaceans are divided primitively into seven segments, which do not follow the naming system used in the other groups. They are: coxa, basis, ischium, merus, carpus, propodus, and dactylus. In some groups, some of the limb segments may be fused together. The claw of a lobster or crab is formed by the

Question: Which animals are arthropods and have eight legs?
Answer: Arachnids