Mucous Membrane in the Human Embryo. 537 
but not against their bases. At the bottoms of the pits the glands 
are seen. These are now longer and more branched, the longest 
measuring about .12 mm. The diameters at the neck vary some- 
what, but most are about .0838mm. The diameters of the branches 
are smaller than the main stem of the gland. The glands are lined 
by a simple epithelium of irregular or polyhedral cells. Both 
the chief and the parietal cells are abundant. The bases of the 
glands lie close to the muscularis mucosae, which at this stage is 
well developed and consists of several distinct strands of smooth 
muscle fibres. 
The changes that take place in the stomach epithelium from 
the 187 mm. stage are merely those in the increase in numbers 
and growth of the structures already formed. At 240 mm. the 
gastric pits measure from .102 to .158. mm., and the glands about 
85 mm. to .186 mm. in length. From this it can be seen that 
the growth of the glands has been more rapid than that of the 
pits, some of the glands now being longer than some pits. Ina 
model of the epithelium of the fundus of the stomach at 240 mm. 
(not figured), gastric pits are more irregular in form but are 
broader across their tops than those of the 120 mm. stage. They 
are, moreover, further apart than before. Fig. 13 shows gastric 
glands modelled under higher magnification. Two types of glands 
are seen, the smaller simple ones and the larger branched. In the 
compound glands the branching is not confined to any particular 
level, but branches are given off at the neck or any level below it. 
The cells lining the pits are like those found in the preceding 
stages, the chief and parietal cells being more numerous than 
before. 
At birth the structure of the mucosa of the stomach is very sim- 
ilar to that found in the adult. The gastric pits are only slightly 
deeper than at 240 mm. The surface epithelium is composed of 
high cylindrical mucous cells with oval nuclei and basal processes. 
At the bottoms of the pits the cells are lower but are still distinct. 
As seen in fig. 14 the glands are longer and more branched than 
before. They have small lumina which are lined with chief and 
parietal cells. 
THE AMERICAN JOURNAL OF ANATOMY, VOL. LO, No. 4. 
