Hair cell bundle count locations on the zebrafish saccule. Hair cell counts were sampled at four predetermined locations: 5, 25, 50, and 75% of the total saccular length, as measured from the rostral tip. A 2500 μm2 box was placed at each sampling area and labeled hair cell bundles were counted within each box to determine hair cell density. D= dorsal, R= rostral; scale bar = 100μm.