A man, aged twenty-one, succumbed to concussion of the brain. Attached to the cardiac end of the stomach, just below the diaphragm, there was a cyst the size of a pigeon's egg. Microscopical examination showed the wall of the cyst to be composed of unstriped muscular tissue, which was arranged in two longitudinal layers with a transverse one interposed between them. The wall was well supplied with blood-vessels, and much blood was effused between the muscle-bundles. The cyst was lined by a single layer of stumpy epithelioid cells, some of which were cuboidal.-Hebb.