1. Good, R. A., Finstad, J., Pollara, B., and Gabrielsen, A., in Phylogeny of Immunity, p. 149 (University of Florida Press, Gainesville, 1966).
2. Cooper, E. L., in Contemporary Topics In Immunobiology, 2: 13 (1973).
3. Du Pasquier, L., in Current Topics In Microbiology and Immunology, 61: 37 (1973).
4. Cooper, E. L., in Physiology of Amphibia, 3 (1975, in press).
5. Cooper, E. L., J. Morphol., 122: 381 (1967).