Location of structurally similar areas in chinchilla cochleas of different lengths

Abstract

In chinchillas the length of the organ of Corti varied up to 26% of the mean (18.31 mm). In specimens of different lengths, areas in which the basilar membrane and organ of Corti had the same physical dimensions were located at the same percentage distance along the cochlear partition. Average densities of the inner and outer hair cells decreased with increasing cochlear length. The rate of decrease in density was less than the rate of increase in length. Long cochleas apparently have a greater amount of the organ of Corti (and hence more sensory cells) in a given frequency region.