Section of a Volute of an Ionic Capital
These volutes, or scrolls, when viewed from the side, appear to meet in the middle, and form a wavy line over the echinus. The intervals of the spiral coils are slightly hollowed, in order to bring them into more relief, and in this way the so-called channel is formed, which is continued in the horizontal portion which connects the volutes.
A. Rosengarten, W. Collett-Sandars A Handbook of Architectural Styles (New York, NY: Charles Scribner's Sons, 1895)
Courtesy the private collection of Roy Winkelman