THE OLFACTORY O&GAN 



229 



possess a small cytoplasmic body and two processes, a distal and a 

 central. Their nuclei are spherical and are disposed in several 

 rows beneath the nuclear zone of the sustentacular cells; thus 

 they form a broad zone of spherical nuclei. The distal process of 



FIG. 194. THE OLFACTORY MUCOSA OF A CAT. 



a, epithelium ; &, basement membrane ; c, corium ; d. cuticle ; e, sustentacular cell 

 layer; /, olfactory cell layer; </, basal cells; ft, blood vessel; t, a tubule of Bowman's 

 giaiids ; fc, bone. Hernatein and picro-fuchsiu. Photo, x 270. 



the olfactory cell projects as a slender filament whose free end, 

 carrying several fine cilia, reaches the surface of the membrane 

 through a pore-like opening in the cuticular membrane which 

 is formed by the cuticle of adjacent sustentacular cells. The 

 central process of the olfactory cell penetrates to the tunica pro- 

 pria and becomes a non-medullated nerve fibre of one of the many 

 rami of the olfactory nerve ; it passes to the olfactory bulb, where 

 its terminal arborization with the dendrites of the mitral cells 

 forms the olfactory glomeruli. 



The Basal Cells are flattened cells which form the deepest 

 nuclear zone of the olfactory neuro-epithelial layers. Their cyto- 

 plasm is finely granular and their nuclei are ovoid or flattened. 



