Ciliary orientation: controlled by cell membrane or by intracellular fibrils?

The cirri of the ciliate Euplotes all asslumne the "reversed" orientation whenever the cell is depolarized and the "forward" orientation whenever the cell is hyperpolarized. Potenitial changes arise spontaneolusly or are induced by electrical or mechanical stimuli. The orientation responses of thte cirri are appatently independent of intracellular "neuromotor" fibrils previously assigned a coordinating function, as they persist after the fibrils are transected.