A new genus, Socalchemmis is established for one of the three main groups of spiders from California and adjacent areas that are closely related to the Appalachian genus Liocranoides Keyserling. Although only one species belonging to the genus appears to have been described, as Anachemmis dolichopus Chamberlin, the genus includes two species groups and at least 15 additional species. Eleven new species are described from California: S. gertschi, S. bixleri, S. shantzi, S. cruz, S. monterey, S. icenoglei, S. cajalco, S. palomar, S. idyllwild, S. miramar and S. prenticei; one new species (S. kastoni) is apparently widespread in southern California, Arizona, and Baja California Norte, and three other new species (S. rothi, S. williamsi and S. catavina) are described from northern Baja California Norte.