Sentence:  The heptatonic system above must be radically segregated from an older model described in UET VII, 74, where the generative paradigm comes from an instrument fitted with nine strings, the <WSD>enneachord</WSD>, exposing the theory of a nine note system that is called enneatonism. 
Meaning of the word marked with <WSD> tags:  An ancient Greek nine-stringed musical instrument.