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The inner ear, which is found in all jawed Vertebrates, functions both as an auditory system that detects sound waves and a vestibular system which detects linear and angular accelerations, enabling the organisms to maintain balance. In fish, the inner ear is a paired structure embedded in the cranium on either side of the head dose to the midbrain. Each ear is a complicated structure of canals, sacs and ducts filled with endolymph, a fluid with special viscous properties (fig. II. A. 1). The gross anatomy of these labyrinths and the structure of the labyrinthine mechanoreceptor organs are known from many fish species (Lowenstein, 1971). Teleosts have three semi-circular canals arranged orthogonally to each other, which detect angular accelerations. The canals open into a series ofexpanded interconnected chambers or otic sacs that contain a sensory tissue, the macula, that detects both linear accelerations and sound. In Osteichthyan species there are three such otic sacs, each containing a calcareous structure, an otolith, that acts as a mechanoreceptor stimulating the kinocilia (" hair" cells) of the macula. The three otic sacs are the sacculus, utriculus and lagena, which contain the sagitta, lapillus and asteriscus otoliths, respectively (fig. ItA. 1). Each otolith is fixed over the macula by an otolithic membrane, into which sensory cilia project. According to Dunkelberger etal.(1980), the otolithic membrane consists of two zones: a structured gelatinous zone that covers the sensory region of the macula, which usually exhibits a reticulated or honeycomb architecture, and the sub-cupular zone, which consists of very loose networks of fibres covering sensory …