Inner ear in dearisch mice (a-d) Inner ears show no sign of abnormal gross morphology: (a, b) unaffected mouse; (c, d) affected dearisch mouse. (a, c) Inner ear viewed from the middle ear side. (b, d) Inner ear viewed from the brain side. The leftwards-pointing arrowhead indicates the round window and the rightwards-pointing arrowhead indicates the oval window; CC, common crus; Co, cochlea; L, lateral semicircular canal; P, posterior semicircular canal; S, superior semicircular canal. (e-j) Scanning electron microscopy at 50% of the distance along the length of the organ of Corti showing normal ultrastructure: (e-g) from unaffected mouse; (h-j) from affected dearisch mouse. (e, h) Normal organ of Corti layout with three rows of outer hair cells and one row of inner hair cells. (f, i) Outer hair cells with a normal morphology. (g, j) Normal inner hair cells. The whole length of the organ of Corti was examined at 10% intervals and no abnormalities were detected (data not shown). Scale bars: 1 mm (a-d); 10 μM (e, h); 1.5 μm (f, g, I, j).