The occurrence and distribution of terrestrial isopods (Oniscoidea) on Santa Cruz Island with preliminary data for the other California islands by R. Garthwaite, F. G. Hochberg, and C. Sassaman. Bull. Southern California Acad. Sci., 84(l):23-37, 1985. During September and October of 1982 sixty locations on Santa Cruz Island, California, were examined for the presence of terrestrial isopods. Isopods were found at 58 of these locations. Thirteen terrestrial isopod species were found— seven littoral species and six non-littoral species. Eight of these species are Pacific coast endemics, three others are European introductions, and two are of uncertain origin. Terrestrial isopods on the island were found to be nearly as diverse as those on the adjacent mainland both with respect to the total number of species and the average number of species per collection site. The local distributions of littoral species on the island reflect the distributions of their preferred microhabitats. Microhabitat may also affect the distribution of non-littoral species, although there may be a significant historical component to their current distributions. Preliminary collection data are given for the other southern California islands.