@212man
I believe you are mixing Somatagravic with Somatogyral.
Yes,
212man you are correct. I've didn't know that the two illusions of acceleration and movement came from two different parts of the vestibular organs (the two otoliths and the semi-circular canals).
As you said, the first is described as Somatogravic and the second Somatogyral. In my years of aviation I have never discriminated between the two!
In the absence of strong visual and other sensory inputs both sensors of the vestibular organs may be involved in false orientation/spatial awareness.