BONE formation in the skin, apart from calcinosis cutis, occurs in several forms: (1) in solitary growths in scars of surgical or other trauma; (2) in ossifying plaques in sclerodermatous diseases; (3) in nevi; (4) in epidermoid carcinomas; (5) in multiple small nodules in children, apparently from embryonic cell rests; (6) in metastatic osteogenic sarcoma, and (7) in miliary nodules in skin damaged by previous pathologic processes. It is with the last type that this report is concerned. In the cases previously reported, such as those of Hopkins1 and Leider,2 acne was apparently the predisposing disease. In other similar cases, such as those of Virchow3 and Arzt,4 no such process was noted. Syphilis has been presumed to be a factor in one case5 in which bone was formed in a chronic leg ulcer, but otherwise this disease has not been reported in predisposition to osteomatosis.