Animal medium-sized to large, topped by a limpet-shaped shell that protects the visceral mass. The differences with Tylodinidae are anatomical: the animal is globular and pustulose in Umbraculidae, elongated and smooth in Tylodinidae.
 

« Shell external, orbicular, slightly irregular, almost flat, a little convex above, white, with a small apical tip towards its middle; edges sharp. The internal face is a little concave, and displays a callous disc, coloured, pressed in the center, and surrounded by a smooth limbus. » – J.-B. M. de Lamarck: Histoire naturelle des animaux sans vertèbres vol.VI part.1, Paris 1819, p.340.