A scanning electron microscopic study of the sacculus and lagena in the ears of fifteen species of teleost fishes

Abstract

The ulstrastructure of the saccular and lagenar maculae were studied in 15 species of teleost fishes, using the scanning electron microscope. Particular attention was paid to hair cell orientation patterns, composition of the ciliary bundles on the hair cells, hair cell distributions, and supporting cell types. The hair cells on both otolithic organs are divided into several groups with all of the hair cells in each group oriented in the same direction. The posterior region of the saccular macula in all species had dorsally oriented hair cells on the dorsal half of the macula and ventrally oriented hair cells on the ventral half. The cells on the anterior end of the macula were oriented anteriorly and posteriorly, with the posterior group, in most species, being on the dorsal half of the anterior region of the macula. There was considerable inter-specific variation upon this basic pattern. Inter-specific variation on the lagenar macula was considerably less than on the saccular macula. The basic pattern in all of the species includes one dorsal cell group and one ventral cell group. There are four more-or-less discrete ciliary bundles, each varying in the relative size of the kinocilia and stereocilia. Intermediary forms were also observed, making it difficult to differentiate ciliary bundles in some instances. It was apparent, however, that several of the ciliary bundles were found in particular macular regions.