1. Cancer Research Institute and Department of Chemistry and Biochemistry, Arizona State University, P.O. Box 872404, Tempe, Arizona 85287-2404, Natural Products Branch, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, P.O. Box B, Frederick, Maryland 21702-1201, and Queensland Museum, P.O. Box 3300, S. Brisbane, Queensland, 4101 Australia