510 Edwin G. Kirk. 
epithelium and tubules cohering so that the whole epithelial area 
loosens en masse. This tendency is observable from 14 to about 
20 cm. in almost all stomachs, and is doubtless referable to the 
shallowness of the pits, taken in conjunction of course, with the 
fixation shrinkage. 
The upper } or + of the primary cardiac tubule, devoid of parie- 
tals and lined by goblet cells, represents the adult foveola, for 
the lineage may be traced, without any break of continuity, to 
the 29 em. stage, long before which all the cena parts of the 
tubule are readily distinguished. The lower 3 or #, lined by groups 
of parietals, interspersed with a large amine of mucous cells, 
gives rise later (20-22 em.) to the tubules proper. 
At 15 em. certain of the groups of parietals begin to push 
outward slightly (fig. 16). These invaginations, at first shallow, 
may occur wherever groups of parietals occur,—namely, in 
the depths of the tubule, and in all but the upper quarter. A¢ all 
stages they consist entirely of parietals. They appear with in- 
creasing frequency in the later stages, and become definite, 
secondary tubules (figs. 17 and 18) by 18-19 em. Those from 
the sides of the pomary tubule are directed outward and down- 
ward; those from the bottom, straight downward. These sec- 
pada tubules are narrower than the primary ones, and at 19 
em. vary from the merest incipient outpouchings to complete, 
though short, tubules. No similar process occurs in the fundvs 
or pylorus at any stage.” 
About 20 em., the compounding of the lower part of the prmary 
tubule occurs in the usual way, so that, at 22 em., several tubules 
open into a foveola. Some of these tubules are purely of parietal 
cells; these were partially derived from the parietal evaginations. 
Some are purely of mucus cells. Many display both types, and in 
all proportions. These three types of cardiac tubules persist up to 
the time of birth (29 em). I do not believe that the formation of 
these parietal tubules differs in essential mechanism from the or- 
12 This unexpected finding agrees absolutely with Toldt’s observation in the cat, 
that some tubules arise as lateral buds, which grow out and downward. They arise 
at a parietal cell, and the latter by division goes over into the new tubule. 
