On the Histogenesis of Gastric Glaads. 509 
extends into some of the tubules, sometimes to the very bottom. 
These deep mucous cells are then of the mucous chief type, the 
whole cytoplasm distal to the nucleus being infiltrated by the 
stainable substance. Thus, mucous differentiation occurs much 
later than in the pylorus, and somewhat earlier than in the fundus. 
However, the process lacks uniformity, for, as late as 14-15 cm. 
the cardia of some embryos exhibits mucous cells only on the 
surface, and a short distance into the tubule, with only an occa- 
sional one in the deeper parts of tubules. 
The parietals, are, of course, unstained in muchematin, but 
are, as always, readily distinguishable (as, indeed, even in un- 
stained specimens, fixed in Bensley’s fluid) by high refractility, 
absolute opacity, and glistening shiny appearance. Moreover 
the ductules are very apparent. The adelomorphs are clear and 
transparent, though very finely granular. 
At 17-18 em. all the cardic cells are either mucous or pari- 
etal. The cells of the surface, for a little way into the tubule, 
possess shallow to deep goblets. The deep cells, aside from parie- 
tals are all of the mucuos chief type. Fig. 14 illustrates the 
typical surface goblet cell (a) and the shallow goblets (b), which 
go over by gradual transitions into the deeper mucous chief cells 
(ec). In some tubules the goblet cells extend quite to the bottom 
but it should be noted that, in embryonic stages, the distinction 
between mucous chief and goblet cells is often not so sharp as in 
adult life, for, in the surface and upper tubule cells, the mucus 
often seems not to be homogeneous, but separated into minute 
goblets by a cytoplasmic mesh. Karyokineses are frequent in 
the mucous chief and goblet cells. Even the deep surface goblet 
cells are found in mitosis frequently. 
From 14 cm. on, a marked form-divergence js added to the 
difference in size between cardiac and fundic tubules, the former 
now becoming shallower (wider relative to the depth), while the 
fundic tubules preserve their accustomed narrower, deeper form, 
so that, after 14 cm. it is easily possible to distinguish the two 
under low power (compare figs. 16, cardia, with 15 and 22, 
fundus). The cardiac epithelium has, from now on, a curious 
tendency to shrink away from the underlying mucosa, surface 
