ULTRASTRUCTURAL CHARACTERIZATION OF THE OLFACTORY ORGAN IN GLASS EELS, ANGUILLA-ANGUILLA (OSTEICHTHYES, ANGUILLIFORMES)

The ultrastructure of the cell type complement of the olfactory epithe lium in glass eels (Anguilla anguilla) is compared with the present kn owledge of the olfactory organs in adult eels and in other fish specie s. In glass eel TEM sections, ciliary and microvillar receptor types a re found. These sensory receptors occur on the central area of the lam ellae and, in contrast to adults, are also located in lamellar infoldi ngs and along the raphe. Peripherally in the lamellae located deep wit hin the epithelium, more electrondense cell clusters consist of spindl e-shaped and oval cells giving off whorls of insunk cilia. These clust ers are interpreted as differentiating units giving rise eventually to ciliated, supporting, and receptor cells.