The τροχὸς in the version of a late 18th-century manuscript of Papadike adds the aspect of the heptaphonic tone system to the peripheral wheels, dedicated to the diatonic kyrios and plagios of the four octaves. In fact, this hybrid form corresponds to the oldest source of the Koukouzelian wheel.Athos, Great Lavra Monastery, Ms. ε 173, fol. 7v was dated 1436 (Alexandru 2013, 21-22, microfilm: 34, discussion of heptaphony: 35-36). The tetraphonic parallage is written outside and just shows the pentachord of protos in the circle on the left top and here its parallage was only written in clockwise direction (see the way marked by the arrows). The psaltes start with the enechema of echos protos, which is descending and ascending stepwise the pentachord with its beginning and end on the kyrios finalis (the pentachord D—a for example).See the old enechemata related to these names.
