Figure Page 14 Photomicrograph of LPS-stimulated alligator peripheral blood lymphocytes 94 15 A chronological study during the winter months of alligator peripheral blood lymphocytes 101 16 Diagram of glass wool fractionation procedures 105 17 Effects of increasing the cell density in mitogen stimulated cultures of alligator peripheral blood lymphocytes 110 18 Immunoprecipitation of lysates of membrane labeled bluegill lymphocytes 137 19 Acrylamide gel electrophoresis in sodium dodecyl sulfate of extensively reduced immune precipitates of bluegill white blood cell membrane immunoglobu lins 140 20 Acrylamide gel electrophoresis in sodium dodecyl sulfate of extensively reduced precipitates of bluegill spleen and thymus membrane immunoglobu lins 142 21 Agarose-acrylamide gel electrophoresis and gel filtration of unreduced immune precipitates of bluegill white blood cell membrane immunoglobu lins 144 22 Acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate of extensively reduced bluegill white blood cell membrane immunoglobu lins fractionated by gel filtration 145 viii