Robert R. Jackson is associate professor of zoology at the University of Canterbury in Christchurch, New Zealand. He earned a B.S. from North Carolina State University in 1968 and a Ph.D. from the University of California, Berkeley in 1976. Address: Department of Zoology, University of Canterbury, Private Bag 4800, Christchurch, New Zealand. Internet: RRJ@zool.canterbury.ac.nz.