Howard A. Schneiderman, 63, chief scientist and senior vice president of the St. Louis-based Monsanto Co., died December 5 of complications associated with leukemia. Schneiderman came to Monsanto in 1979 from the University of California, Irvine, where he was dean of the school of biological sciences and director of the Center for Pathobiology. He conducted research in developmental biology and genetics, including growth control, congenital malformations, and cancer. Under Schneiderman's direction at Monsanto, the company built the Life Sciences Research Center for biotechnology research in Chesterfield, Mo., and established collaborative research products with several universities. Schneiderman graduated from Swarthmore College in 19TK. He earned a master's degree in zoology in 19TK and a doctorate in physiology in 19TK from Harvard University. He was a member of the National Science Board, the American Academy of Arts and Sciences, and the National Academy of Sciences' Council of the Government-University-Industry Research Roundtable.