Pachycheles rudis  Stimpson, 1859

This native species is in a group commonly referred to as the porcelain crabs. They are not considered "true" crabs and are placed in the taxonomic group Anomura. Other anomurans include the hermit crabs and ghost shrimp. The porcelain crabs differ from "true" crabs (Brachyura) in that their fifth pair of periopods (walking legs) are greatly reduced and/or absent. Pachycheles rudis is abundant within dock fouling communities throughout the central Bay, feeding on plankton and detritus which it combs out of the water using the setae (hairs) on its outer maxillipeds (jaw appendages).