[Principles of the structural organization of the chemosensory system of freshwater gastropod mollusks].

Authors own experimental data and data available in literature were summarised to elucidate the influence of the mollusc environment and mode of living on structural organization of tentacular and osphradial systems, receptors of the mouth labia and mantle in typical freshwater mollusc. The similarity between sensory systems of tentacles, mouth and labia was demonstrated based on the findings obtained using silver impregnation, horse radish peroxidase labelling and electron microscopy. Module pattern of organization and peculiarities of sensory organs efferent innervation were demonstrated. Bilateral symmetry and the basis of multichannel structures of sensory systems central regions were described. Specific pattern of structural organization and those common with other animals were shown. The emphasis was made on differences from the olfactory systems of ground gastropods that consist in the lack of olfactory glomeruli, the special olfactory centres, procerebri and specialized chemosensory epithelium in freshwater mollusc.