The olfactorius bulbus and olfactorius tractus were studied by Nissl,H.E. and Haggquist stain in A. Sinensis. In transverse section, the olfactorius bulbus can be divided into distinct eight layers from outer to inner:fiber layer, glomerular layer, outer granular layer, outer plexiform layer, mitral cell layer, inner plexiform layer, inner granular layer and ependymal layer. In transverse section of olfactorius tractus ,pyriform lobe, hippocampus and nucleus olfactorius anterior can be found. The organizati...