The vestibular stereovillus membrane: an illustration of the 'greater membrane' concept.

Sensory epithelia from the vestibular organs of fish, mostly Rutilus rutilus, were investigated by electron microscopy. Conventional thin sectioning combined with labeling and extraction procedures and the use of isolated stereovilli led to the conclusion that the stereovillar membrane together with the membrane skeleton and extracellular material should be considered as a morphological unity. The stereovilli are connected by extracellular material. Similar connections also occur in other vertebrates, suggesting that these connectors are of functional importance to mechanoreception in hair bundles.