| Abstract: | The macula sacculi and the macula lagenae of the herring, Clupea harengus L., were examined by light microscopy, the macula lagenae is large compared to what is normal among non-ostariophysan fishes, the morphological polarization of the hair cells in the inferior maculae shows a pattern which is similar to that usually seen in teleost fishes. The fibres in the nerves supplying the macula sacculi and the macula lagenae were counted and their diameters measured. The ramulus saccularis is divided in two separate ramuli innervating populations of hair cells with different morphological polarization. The saccular rostral nerve trunk contains 1800–2300 fibres, with 1300–1800 fibres in the caudal nerve trunk. The lagenar nerve is composed of 2100–4000 fibres. The fibre diameters are 1–14 μm in all ramuli. Silver staining of the nerve axoplasm reveals a unique differentiation of the maculae, which can be divided into a central area surrounded by a peripheral part. The hair cells in the central area are innervated by thick nerve fibres (5–14 μm diameter) as well as a few thin nerve fibres (about 1 μm diameter), while the receptor cells in the peripheral area are exclusively innervated by thin fibres having diameters of 2 μm or less. |
