<P> With these may be grouped the music of Sudan and of the Horn of Africa, including the music of Eritrea, Ethiopia, Djibouti and Somalia . Somali music is typically pentatonic, using five pitches per octave in contrast to a heptatonic (seven note) scale such as the major scale . The music of the Ethiopian highlands uses a fundamental modal system called qenet, of which there are four main modes: tezeta, bati, ambassel, and anchihoy . Three additional modes are variations on the above: tezeta minor, bati major, and bati minor . Some songs take the name of their qenet, such as tizita, a song of reminiscence . </P> <P> The ethnomusicological pioneer Arthur Morris Jones (1889--1980) observed that the shared rhythmic principles of Sub-Saharan African music traditions constitute one main system . Similarly, master drummer and scholar C.K. Ladzekpo affirms the "profound homogeneity" of sub-Saharan African rhythmic principles . </P> <P> African traditional music is frequently functional in nature . Performances may be long and often involve the participation of the audience . There are, for example, little different kinds of work songs, songs accompanying childbirth, marriage, hunting and political activities, music to ward off evil spirits and to pay respects to good spirits, the dead and the ancestors . None of this is performed outside its intended socialess context and much of it is associated with a particular dance . Some of it, performed by professional musicians, is sacral music or ceremonial and courtly music performed at royal courts . </P> <P> Musicologically, Sub-Saharan Africa may be divided into four regions: </P>

Which of the following is not an important musical instrument from southern africa