On the Histogenesis of Gastric Glands. 499 
It was deemed best to deal with the stomach as a whole in 
the discussion of these earlier stages, up to and inclusive of 
7cm. But inasmuch as certain definite gastric regions have now 
differentiated, the development of these will, in the interest of 
clearness, be followed separately. 
2. Pylorus 
At 9 cm. all the pyloric epithelium, both surface and glandular, 
consists of mucous cells. The deeper tubule cells are of the mu- 
cous chief type, those higher in the tubule have shallow thecae, 
while the surface cells display a mere distal rim of mucus. No 
parietals are present, except in two or three tubules next to the 
fundic zone, and in these only a very few scattered ones. Now, 
as earlier the fundo-pyloric boundary is very definite. If, as 
seems justifiable in the light of the adult structure, our criterion of 
a pyloric tubule be the mucous chief cell-lining of the deep seg- 
ment, then the fundo-pyloric boundary is absolutely sharp. For, 
if adjacent sections stained with muchematin and three color be 
compared, we find that the fundic segment of the fundus glands, 
even the last, has no mucous cells, while, the fundus of the pyloric 
tubules is lined exclusively by mucous chief cells, except for the 
scattered parietal or two in the last two or three tubules toward 
the fundus. 
The pyloric processes are, in general, broader (40-54) than 
those of the fundus (25-40u), but resemble the latter in often 
possessing expanded or clubbed tops. The pyloric tubules usually 
present a very symmetrical test-tube form. Their appearance at 
9 cm. is indicated by fig. 21, for although the latter is taken from 
a much older embryo (19 cm.) yet the change in the pyloric glands, 
after 9 cm. are mainly those of size andof the upgrowthof the en- 
closing ridges rather than any fundamental alterations in form and 
cytology. In the pyloric tubules, as in those of the fundic region, 
there are from now on, many mitoses, and at all depths. They 
also occur in the ridge cells, although not so frequently. 
At 10-11 cm., the deep cells are so packed with mucus that 
the nuclei are often flattened; the goblets of surface and foveola 
cells are also becoming deeper. 
