The study of human teratology has always been rendered difficult by the relative scantiness of available material; consequently it is of great importance that such cases as can be obtained should be fully utilised and recorded. It has seemed to us that in this respect the employment of X-rays is likely to prove of service, for the abnormalities of the skeletal structures can then be readily and fully studied without interfering with the integrity of the specimen or its utility in the investigation of other elements. We therefore desire to place on record the skiagraphic findings of several series of developmental anomalies in the human subject, in order that they may be available for future workers.