394 THE NASAL REGION IN EUTAENIA. 



The nasal bones immediately succeed the ascending process of the 

 premaxilla. They rea^h down between the wings of the nasal 

 septum, and do not pass out fai-ther than the superior border of 

 Midler's Gland. Posteriorly, each have a process directed downward 

 to unite with the process of the inner edge of septomaxillary, when 

 the plate of the latter disappears behind. (Fig. 4, na.) This inferior 

 process is continued into the rostrum of the frontal bone of the same 

 side. 



In the same section as at first examined, viz., that through the 

 middle of the Organ of Jacobson, the mucous membrane of the roof 

 of the mouth differs in structure at the following points : 



(a) At the inner surface of the lip, where large nucleated cells are 

 overlaid by a corneous stratum ; the cells at the base, while of the 

 same size and shape, are more granular in contents. 



(/?) In the immediate neighborhood of the furrow, in which the- 

 ducts of the upper lip gland open ; there the corneous layer is replaced 

 by flattened, apparently squamous, cells overlying a layer of small 

 oval cells. This is the structure of the membrane on the middle 

 palate and in the dental pits. 



(y) In the palatine crypts, where goblet and ciliated cylindrical 

 cells alone are found, the latter being to all appearance the more 

 numerous. 



(6) At the passage from one palatine crypt to another, where the 

 membrane is formed almost wholly of ciliated epithelium cells, with 

 here and there a goblet cell. 



The furrow to be found limiting the inward extension of corneous 

 layer of the lip receives at regular intervals the apertures of the 

 ducts of the upper lip gland. From here the ducts lead upward and 

 outward and break up into a number of acini. Immediately above 

 the lobule thus formed are to be found the sections of preceding or 

 succeeding lobules, three or four in number. The cells of the acini 

 in the uppermost lobules are of larger size than those of the lower. 

 The nucleus in each is generally situated in the outer half of each 

 cell, the contents of which are more or less granular, and slightly 

 pigmented, giving to the gland, as a whole, a yellowish tinge. When 

 removed in a state of active secretion, the cells of the gland are found 

 to be extremely granular. As these approach the main duct they 

 elongate and become cylindrical. The acini are compressed against, 

 each other, thus becoming polygonal in section and are separated by 

 small quantities of nerve fibres and connective tissue. 



