An apparently unique case is described[long dash]a stillborn full-term human [female] fetus showing as sole malformation a bilateral synostosis between humerus and radius, with no deformity of the ulna. Reconstructions of the elbow joints in 10 fetuses (14-38 mm.) revealed no stage that could be considered as corresponding to this malformation . The etiology is therefore unknown, and, so far as could be ascertained, neither parents nor relatives presented any kind of malformation.