336 ELEMENTS OF HISTOLOGY. [Chap.XLii. 



oval, nucleus the sensory cells (Max Schultze). 

 Each cell sends one broad process towards the free 

 surface, over which it projects in the shape of a small 

 bundle of shorter or longer rods ; whereas a fine 

 varicose filament passes from the cell body towards 

 the mucosa, and, as shown first by M. Schultze, be- 

 comes connected with a fibrilla of the network of the 

 olfactory nerve-fibres. 



(c) In some places there is a deep layer of epithe- 

 lial cells, each with a spherical nucleus, of an inverted 

 cone in shape, their pointed extremity passing be 

 tween the other cells just mentioned and their broad 

 basis resting on the basement membrane. Von 

 Brunn has shown that there is on the free surface of 

 the epithelium a sort of cuticle a delicate limitans 

 externa. 



491. The mucous membrane is of loose texture, 

 and contains a rich plexus of bundles of olfactory 

 nerve-fibres, extending chiefly in a direction parallel 

 to the surface. Each olfactory nerve-fibre is non- 

 medullated, i.e., is an axis cylinder composed of minute 

 or primitive fibrillae, and invested in a neurilemma with 

 the nuclei of the nerve corpuscles. Near the surface 

 the fibres of the plexus are thin, and they split up 

 into the constituent fibrils which form a network ; into 

 this pass the fine varicose processes of the sensory 

 cells above named. 



492. The blood-vessels supply with capillary net- 

 works the superficial part of the mucous membrane 

 and the numerous glands. These are the (/lands of 

 flowman, extending through the thickness of the 

 mucous membrane. They are tubes, slightly branched, 

 and gradually enlarging towards their distal end ; in 

 some parts they are more or less straight. In struc- 

 ture they are identical with serous glands, possessing 

 a minute lumen, and being lined with a layer of 

 columnar albuminous cells. The duct is a very fine 



