Growth of a fish ear. II. Locations of newly proliferated sensory hair cells in the saccular epithelium of Astronotus ocellatus.

Tritiated thymidine was used to investigate the sites of postembryonic hair cell addition in adult fish Astonotus ocellatus (oscar), a species known to add large numbers of hair cells for several years after hatching. Several types of labeled cells, including newly proliferated sensory hair cells, were found throughout the saccular epithelium, with the majority of the cells some distance away from the edges of the epithelium. There was no evidence for an 'annular' addition of sensory hair cells in Astronotus.