The xylorimba (sometimes referred to as xylo-marimba or marimba-xylophone) is a pitched percussion instrument corresponding to a xylophone with an extended range (and not to a combination of a xylophone with a marimba, as the name might suggest).
Like the xylophone and marimba, the xylorimba consists of a series of wooden bars laid out like a piano keyboard "with a compass sufficiently large to embrace the low-sounding bars of the marimba and the highest-sounding bars of the xylophone."
"The lower notes of the xylorimba sound like a xylophone rather than a marimba on account of the bars being thicker and narrower than those of a marimba (the bars of the xylophone and the marimba are shaped differently to emphasize different overtones) and of the different size and shape of the resonators" (Blades and Holland n.d.).
The usual playing range of a modern xylorimba is five octaves: from the C one octave below middle C to the C four octaves above middle C (C3 to C8). It is a transposing instrument, since music for xylorimba is written an octave lower than it sounds, using a grand staff with both bass and treble clefs.