372 E. A. BAUMGARTNER 
In the specimen from a child of five years, as also in speci- 
mens from older individuals, mucous glands, either as single 
alveoli or in groups, join the ducts of serous glands. Occasion- 
ally a part of an alveolar group is formed of serous cells, which 
are succeeded by cells distinctly mucous in type. 
A reconstruction of the glands from a twenty-two year old 
specimen shows anastomoses between the closely crowded alveoli. 
Some of the glands are somewhat tubular, although they gen- 
erally appear to be more of the alveolar type (figs, 9 and 10). 
The main ducts are distinctly different in structure from the 
end pieces, but the terminal ducts, breaking up within a group 
or lobule, may be similar to the glandular end-pieces. Anasto- 
moses occur between alveoli of two terminal ducts as well as 
between those from one duct (fig. 9). Irregular outgrowths 
of the main ducts noted in younger specimens are present also 
in this specimen; these outgrowths extend in every direction 
and some are just beginning to break up into end-pieces (fig. 9). 
Figure 9 shows a gland from one terminal duct anastomosing 
with one of these gland anlagen. The lumen in the specimen 
could not be traced from one duct to the other through the gland 
mass. However, the lumens are sometimes very minute, even in 
larger end-pieces. Figure 10a shows an alveolar-like end- 
piece connected with the terminal duct; from the former three 
alveolar-like end-pieces project in various directions. Figure 
10 shows a group of glands from which a portion has been re- 
moved in order to show the terminal duct with its various 
end-pieces. 
The histological structure of the serous glands from the 
twenty-two year old specimen varies greatly. In some of the 
glands the secreting cells are large and deeply-stained; in others 
the lumens are large, whereas the cells appear flattened. These 
differences are probably due to different stages of functional 
activity. . 
Serial sections of a vallate papilla from a man fifty years old 
presented very closely crowded glands. 
Although this work is mainly a study of the development of 
the serous glands and their topographical relations, some at- 
