514 Edwin G. Kirk. 
tubules. These glands display the same form-development as 
the others. They are more precocious than the cardiac tubules, 
and deeper progressively, keeping pace with the pyloric tubules 
in development. At 11 em. they still consist of clear, trans- 
parent cells. At this stage, then, we find the major and central 
portion of the pars oesophagea to be of stratified squamous epi- 
thelium; outside this is a zone of simple columnar epithelium 
which displays the glands at the very periphery. At 11 cm. the 
boundary between the clear cells of pars oesophagea and granu- 
lar cells of adjacent cardia, fundus and pylorus is sharp to a cell. 
I have not been able to settle definitely the fate of this glandular 
zone in later stages. It seems, by differentiation of the cells, 
to merge with the adjacent cardia. 
6. Conclusions and theoretical deductions 
a. Homologies and phylogeny of the cardia 
We have seen that fundic and cardiac glands display an abso- 
lutely parallel development in the earlier stages, the cardia, how- 
ever, lagging behind, from the first. In each the parietals appear 
at a corresponding stage. It is impossible to distinguish an iso- 
lated 8 em. fundic from a 12-13 em. cardiac gland. After 138-15 
em. however, development in the cardia is retarded; while the 
fundic tubules elongate rapidly and become narrow, the cardiac 
tubules lengthen but slowly, and assume a shallow contour. 
At the same time a significant parallelism appears in the cyto- 
differentiation. The foveolar region of each, with goblet cells, 
appear to be, at all stages, homologous. The lower part of the 16- 
17 cm. cardiac tubules corresponds, cytologically, to the neck 
region of the young fundus tubule, each being composed of mucous 
chief and parietal cells. The length of the whole cardiac tubule at 
this stage, is about that of foveola plus the neck of the fundus 
gland. 
In the fundice gland of 20 em. the body and neck segements 
become compound. In the cardiac gland of 25 em. the body seg- 
ment is evidently absent, barring the very temporary appearance 
