A connecting device is provided including one or more connecting elements arranged on at least one connectable part. At least one connecting element includes non-self-cutting retaining projections having a curved supporting surface in the form of an arc of a circle in longitudinal section. A groove is provided in one of the connectable parts, the groove having a curved undercut surface in the form of an arc of a circle in longitudinal section and including a base section and two undercut sections which extend away from the base section in a thickness direction. The retaining projections are engageable with the undercut sections of the groove. One or more connecting elements include or are in the form of one or more screw elements, and one or more connecting elements include one or more moveable retaining elements by means of which the parts can be drawn towards and/or pressed against each other.