ULTRASTRUCTURAL-STUDY OF THE OLFACTORY EPITHELIUM OF TRICHOMYCTERUS-BRASILIENSIS (REINHARDT) (PISCES, SILUROIDEI)

The epithelium surface of the olfactory organ of Trichomycterus brasil iensis was studied by scanning electron microscopy. The olfactory lame ly is thin and set in groups of 8 to 9 in a single rosette. The sensor y epithelium consists mainly of two groups of cells: non-sensory and s ensory cells. In the first group type 1 ciliated cells and supporting cells were found, and in the second group, type 2 ciliated cells and m icrovillous cells. The floor of the ''lamelli'' is covered by the four kinds of cells mentioned above, mainly of type 1 ciliated cells and t he supporting cells. The sensory epithelium contains few globet cells and the microridges found on the surface of some epithelium cells have atypical organization. Such characteristics classify this species as a macrosmatic species (high olfactory capacity).