MINUTE ANATOMY OF NASAL MUCOUS MEMBRANE. 113 
tance. Where there is on the surface stratified pavement epi- 
thelium, the stratum corneum above mentioned is also continued 
for a short distance into the duct, as I have mentioned in my 
paper in the October number of this Journal, 1880. 
The ducts possess a relatively large lumen, and are lined with 
a single layer of columnar cells, whose outer part is very conspi- 
cuously striated, and whose nucleus is spherical, and situated in 
about the middle of the cell; they resemble, therefore, com- 
pletely the salivary tubes of Pfluger. The diameter of the 
ducts varies between 0:048 and 0°06 mm., the lumen being 
between 0°012 and 0:024 mm. The structure and size of the 
alveoli are in all respects identical to those described above of 
the aveoli of the serous glands of the other parts. 
In some places the layer of these serous glands is much 
thicker than in others; in such cases there are bundles of un- 
striped muscle cells to be traced between the alveoli, forming in 
some places a plexus, and acting then as the matrix of the gland 
alveoli. The large veins, mentioned above, appear in this case 
also embedded in a tissue containing unstriped muscular tissue, 
and hence the appearances are produced not unlike those of a 
cavernous tissue (see my paper in this Journal, October, 1880). 
I have given an illustration of these relations in the ‘ Atlas of 
Histology,’ plate xlvi, fig. 20. 
VOL, XXI.—NEW SER. H 
