This is a list of instruments by Hornbostel-Sachs number, covering those instruments that are classified under 321.21 under that system. These instruments may be known as bowl lyres.
32: Instruments in which the resonator and string bearer are physically united and can not be separated without destroying the instrument
321: Instruments in which the strings run in a plane parallel to the sound table (lutes)
321.2: Instruments in which the string is attached to a yoke that consists of a cross-bar and two arms, with the yoke lying in the same plane as the sound-table (lyres or yoke lutes)
321.21: Instruments in which the resonator is bowl-shaped, either carved or natural
These instruments may be classified with a suffix, based on how the strings are caused to vibrate.
von Hornbostel, Erich M.; Curt Sachs (March 1961). "Classification of Musical Instruments: Translated from the Original German by Anthony Baines and Klaus P. Wachsmann". The Galpin Society Journal. 14. Galpin Society: 3–29. doi:10.2307/842168. JSTOR842168.
^Wachsmann, Klaus (1964). "The Migration of Musical Instruments: Human Migration and African Harps". Journal of the International Folk Music Council. 16: 84–88. doi:10.2307/835087. JSTOR835087.
^Roberts, Helen (February 1981). "Reconstructing the Greek Tortoise-Shell Lyre". Archaeology and Musical Instruments. 12 (3): 303–312. doi:10.1080/00438243.1981.9979805. JSTOR124242.
^Nidel, Richard (2005). World Music: The Basics. Routledge. pp. 58. ISBN0-415-96800-3. Much of Kenya's music is derivative of other Afropop forms, most obviously Congolese, but the singing, high-pitched guitar work, use of the national instrument, the nyatiti (a seven-stringed harp), and bottle percussion give it a unique, identifiable sound.
^Radano, Ronald Michael; Philip Vilas Bohlman (2000). Music and the Racial Imagination. Houston A Baker, Jr. and Houston A. Baker. University of Chicago Press. ISBN0-226-70199-9.