LIST OF TABLES Table Page 1 White Cell Differentials of Bluegill Whole Blood and Hypaque-Fic.oll Isolated Blood Cells 22 2 Effect of Dialysis of Plasma Supplements on Mitogenic Stimulation of Bluegill Anterior Kidney Lymphocytes. 26 * 3 Effect of Maintenance Time of Bluegill in Laboratory Aquaria on Differential White Cell Counts of Hypaque-Ficoll Isolated Anterior Kidney Cells. ... 28 4 Effect of Maintenance Time of Bluegill in Laboratory Aquaria on the Incorporation of Thymidine by Unstimulated Anterior Kidney Cell Cultures 30 5 Mitogenic Responses of Bluegill Thymus Lymphocytes. . 39 6 Mixed Lymphocyte Responses of Bluegill Anterior Kidney Lymphocytes 41 7 Mitogen Responses of Bluegill Anterior Kidney Lympho cytes Treated with Anti-Brain Plus Complement or Rosette Depleted with Rabbit Red Blood Cells .... 43 8 Rosette Formation of Bluegill Anterior Kidney Lympho cytes with Red Blood Cells from Heteiologous Species 44 9 Distribution of Antibody Forming Cells in Various Tissues of Bluegill Immunized with Sheep Erythrocytes. ... 46 10 Immunoglobulin Producing Cells in the Lymphoid Organs of the Bluegill 48 11 Primary In. Vitro Immunization of Bluegill Lymphoid Organ Cell Suspensions with Sheep Red Blood Cells 50 12 White Cell Differentials of Alligator Whole Blood and Hypaque-Ficoll Isolated Blood Cells 71 13 PHA Responses of Alligator Peripheral Blood Lymphocytes Cultured with Different Alligator Serum Supplements. 74 v