The existence of four types of cells in the glomerular outgrowths from both normal and nephritic rabbits was confirmed, and their characteristics by phase contrast, scanning electron, and transmission electron microscopy are described. Type I (arborized), Type I1 (fusiform), Type I11 (round), and Type IV (paving stone-like) cells presumably originate from visceral epithelial cells, mesangial cells, monocpes, and parietal epithelial cells of Bowman's capsule, respectively, though conclusive evidence is still lacking. The Type I11 cells, unlike the other types of cells, have a remarkable phagocytic capacity as well as Fc and C3 receptors. ACTA PATHOL. JPN. 30: 917-926, 1979.