Our object in this paper is to call attention to a surgical condition the origin of which is obscure and the diagnosis of which is seldom made except at operation. In 1908, one of us1 (J. S. D.) published a report of a study on primary hemangiomas of the muscle, with a review of the literature up to that time, and added six hitherto unreported cases to the 147 cases found in published reports. We wish to add to this number eleven new cases, and we have taken this opportunity of reviewing the literature of the past twenty years and of bringing the subject up to date. Since 1908, forty-eight cases have been added to the 153 gathered in the previous report, with which the eleven cases to be outlined make a total of 212. In March, 1843, Liston described the first case, which he called an erectile tumor