These are the scorpions, spiders, mites, horseshoe crabs, and "sea spiders." Chelicerates have six pairs of appendages, which are uniramous (unbranched). These include a pair of chelicerae, a pair of pedipalps, and four pairs of walking legs. Chelicerates lack mandibles and antennae. Respiration is by means of book gills, book lungs, or tracheae.
We have more information on the subgroups of chelicerates, use the Classification tab to find them.
Hickman, C.P. and L. S. Roberts. 1994. Animal Diversity. Wm. C. Brown, Dubuque, IA.
Brusca, R. C., and G. J. Brusca. Invertebrates. 1990. Sinauer Associates, Sunderland, MA.
Phil Myers (author), Museum of Zoology, University of Michigan-Ann Arbor.