A total of 58 species, representing 48 genera of sponges, was collected from southern California (depth 0-1865 m) during 1976-1978. Twenty-two species show geographical range extensions and 1 2 species had depth range extensions. Oxymycale is synonymized under Mycale. Stelleta clarella is synonymized under S. estrella. The biogeography of sponges of the southern California borderlands is discussed.