ME NINGIOMAS of the posterior cranial fossa are difficult to diagnose but, when detected, are often amenable to surgical removal. The clinical, roentgen, and surgical features of these lesions have been ably described in the comprehensive treatise by Castellano and Ruggiero in 1953 (5) and in other reports (4, 6-8, 1518,21,26,34,39- 42). It is the purpose of this article to present the findings observed in patients at the Graduate Hospital and the Hospital of the University of Pennsylvania from the year 1918 through 1955. The study is based on the records of 59 of 64 patients, most of whom were operated upon by Dr. Francis Grunt3 and Dr. Robert Groff.4 Radiographs were available for review in only 26 cases; in the others the radiologic interpretations were consulted. Incidence This series represents approximately 1 in 12 of all patients with verified intracranial meningiomas operated upon by Grant and Groff, a proportion similar to that reported by Cushing and Eisenhardt (7), Dandy (see Gonzalez Revilla, ...