1. Department of Veterinary Biosciences, University of Illinois (D.L.B., T.S., P.S.C.), Urbana, Illinois 61802;
2. Departments of Biochemistry and Child Health, University of Missouri (J.A.T., D.B.L.), Columbia, Missouri 65211
3. Department of Anatomy, University of California (T.K., G.R.C.), San Francisco, California 94143;