The question of congenital deformities and defects of the extremities is attractive because of the richness of different morphologic manifestations; it is difficult when it comes to the systematic grouping of observations, and it is extremely embarrassing when etiology is concerned. It seems that with all the scientific armamentarium of modern physicians, they are approaching the problem merely from another side and have not yet succeeded much more in detecting the underlying cause than had the observers of many hundred years ago, who interpreted the various monsters as lusus naturae. Nature, or a great vital force, in incalculable mood, enjoys and diverts itself by producing the most abstruse forms. The more modern conceptions are more mechanistic, and the thin amniotic membrane especially has frequently been accused of being responsible for the development of congenital deformities, either by inflammatory adhesions or simply by decreased amount of amniotic fluid. No doubt for