The anatomy of the peripheral auditory system of the alligator lizard, Gerrhonotus multicarinatus, is described. The histology of the auditory receptor (basilar papilla) is described in detail and compared with the mammalian organ of Corti. Special features of the cochlear anatomy are correlated with intracellular responses recorded within the basilar papilla. The cochlea of the alligator lizard is a suitable preparation for combined morphological and electrophysiological investigations of sensory transduction at the cellular level in a vertebrate inner ear.