Diverticulum formation in the alimentary tract is a common occurrence and the radiological demonstration of such lesions is exceedingly frequent. Diverticula are commonest in the descending and pelvic loops of the colon, but they not infrequently occur at other sites extending from the pharynx to the rectum. It is rare, however, to find diverticula in the vermiform appendix. Pathologists state the incidence varies from 0·2 to 2·23 per cent in post-operative and necropsy findings (Konjetzny, 1909; MacCarty and McGrath, 1911; Moschcowitz, 1919; Stout, 1923). In 1923, Stout discussed the aetiological factors of diverticulum formation in the appendix in his exhaustive study of a large number of cases and concluded that the lesions are mainly acquired and of the pulsion variety. They occur at sites of weakness in the muscular wall at those points on the mesenteric border where the musculature is pierced by blood vessels. Collins (1936), in an extensive study of the previous literature, coupled with his own fin...