Introduction Basal-cell carcinoma has interested scores of investigators because it is seemingly a biologic enigma. It appears that a tumor derived supposedly from the more primitive epidermal basal cell is biologically less active or malignant than a tumor derived from the maturer "child" of the basal germinative cell, the prickle cell. This situation appears unique in the skin: Tumors of squamous epithelial mucous membranes, such as the cervix of the uterus, gingiva, buccal mucosa, esophagus, and the like, also apparently of basal-cell origin, follow the rules, and are more malignant than tumors presumably of the maturer prickle cell. The purpose of this report is to clarify and enlarge upon our previously expressed attitude (Smith and Swerdlow), namely, that basal-cell tumors arise from hair anlage. It is my feeling now and the thesis of this report that basal-cell carcinoma is less malignant than prickle-cell carcinoma because it represents an abortive