Quadrans Muralis, or the Mural Quadrant, is an obsolete constellation which was located between Draco and Bootes. It is primarily of interest today because a meteor shower (the Quadrantids) is named after it.
     A mural quadrant is a device mounted parallel to the celestial meridian, to accurately observe the altitudes of stars. An illustration of Tycho Brahe's mural quadrant is shown below.