The response of statocyst receptors of the lobster, Homarus americanus, to movements of statolith hairs.

1. While recording from the statocyst nerve of Homarus americanus, we deflected the statolith hairs from the "rest" position they assumed after the lith was removed. 2. Each of the smaller statocyst hairs apparently drove three sensory receptors; all receptors were sensitive to hair position, hair movement velocity, and hair movement direction. 3. Two of the receptors, types A and C, only responded when the hair was lifted up and away from rest; the third, type B, only responded vigorously when a hair was moved back toward rest from such a deflexion. 4. Type A and B receptors were phasic-tonic; type C receptors were phasic.