a non-cellular structure, evidently the keratinized cells of the underlying epithelium. This layer is about 0.069 mm thick. There is a sharp well defined break between the callus and the immediately underly cell layers. No nuclei or nuclear debris is to present in the callus, but the immediately underlying layer has active complete nuclei. No stratum corundum or granulosum is apparent, the epidermis consisting of variously shaped cells of the stratum Malpighii. The outer layers are flattened into priconical cells, but as they progress deeply they are progressively more evenly polyhedral. These cells are connected to one another by inter- cellular bridges, as typical with epithelial cells of the stratum Malpighii. The cell borders are distinct, transparent, looking like little clear spaces between cells, crossed by the numerous bridges. The stratum germinativum consists of densely packed columnar cells, a layer about 0.035 mm thick. The basal cells in this layer are consistently vacuolated. Dermal papillae containing blood capillaries penetrate the stratum germinativum every 0.050 mm or so. The whole Malpighian layer is about 0.141 mm. thick. The dermis, about 0.17 mm. thick,