Oscillographic Analysis of the Gravity and Vibration Responses from the Labyrinth of the Thornback Ray (Raja clavata)

Abstract

IN a recent communication¹, one of us (O. L.) reviewed the results so far obtained, by the oscillographic method, in the study of the non-acoustic function of the vertebrate ear. In that review a preliminary account was given of the reaction to gravitational stimuli and linear accelerations of the otolith organ in the recessus utriculi of the elasmo-branch labyrinth. It was shown that the otolith organ of the utriculus is sensitive to positional changes about any horizontal axis, and to linear acceleration during straight-line translations. The fact that the organ is not restricted to respond to displacements in only one plane of space invited the conclusion that the utriculus may well be the only otolith organ concerned with the maintenance of equilibrium, leaving the otolith organs of the pars inferior of the labyrinth (sacculus and lagena) free for the reception of vibrational stimuli. This function has, in fact, been conclusively demonstrated to be localized in the pars inferior of the labyrinth of bony fish^2,3.