Comparative anatomical and neurohistological observations on the tongue of the northern fur seal (Callorhinus ursinus)


  • Kinziro Kubota

    1. Department of Anatomy, Tokyo Medical and Dental University, Yushima, Tokyo, Japan
    Current affiliation:
    1. Institute of Stomatognathic Science, Tokyo Medical and Dental University, Yushima, Tokyo, Japan
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Five fetal and ten adult fur seal tongue were investigated. The number and shape of the vallate papillae vary from one to five on the different tongues. They are intermediate between the fungiform and circumvallate papillae in their neurohistological features. There are a few taste buds on the upper surface without a trench. They are supplied by large basal nerve plexuses with many argyrophilic and argyrophobic multipolar nerve cells and by abundant mixed glands with widely dilated ducts opening directly on the dorsal surface. The tongues lack foliate papillae. Fungiform papillae are scanty on the dorsum, and they have a nerve supply but no taste buds in the upper surface. Between the musculature three types of sensory nerve terminations are found: One, a nerve bundle consisting of inner longitudinal and outer circular fibers, two, a ramified complex termination and three a knob ending. The latter two are probably receptors of the internal depth-sense in the tongue. Apical mixed glands are present.