The polarization of hair cells from the inner ear of the lesser spotted dogfish Scyliorhinus canicula

The polarization of hair cells from the end organs of the inner ear from the lesser spotted dogfish Scyliorhinus canicula from the order Carcharhiniforms (ground sharks) was studied using a scanning electron microscope (SEM), revealing arrays of hair cells with diverse orientations on each of the sensory epithelia. The greatest numbers of hair cells were found on the utricular epithelium and orientated on the horizontal plane, whilst the smallest number were found on the anterior macula neglecta and orientated on the vertical plane. Examination of the posterior macula neglecta revealed a dense profusion of c. 500 000 individual elongate structures, each resembling long microvilli, a finding not previously described in elasmobranch auditory physiology.