az Franklin P. Johnson. 
gland formation begins, while in the cesophageal glands it does 
not appear until after the excretory ducts are formed. 
TABLE 1 
OESOPHAGEAL EprtHEettum (Mip Rearon) 
THICKNESS! OF DIAMETER OF 
EMBRYO SURFACE EPITHELIUM | EPITHELIAL PRIMARY FOLDS SECONDARY FOLDS 
TUBE 
= path oes In mm.” In mm. Number Holeht. Number Holes 
7.5 | 3-4 (?%) .020 .043 0 
16.2 3-40) 1) 2048 148 0 
19. 1—-4* .051* . 163 0 
22.8 1-4* lee e0ol= 223 1 .010 
30 2-3 |  .030 306 2 .056 
42 2-3 048 .398 3-(4) .089 
55 2-4 .051 ol a 094 1 012 
99 3-4 051 1.01 + .3l a 081 
120 4-5 048 .90 + .29 + 054 
187 4-5 051 1.63 4 AT 3 091 
240 1.81 4 58 a 127 
Birth 5-6 | .056 2.26 4 .68 3-4 .163 
1 On tops of folds when present. 
2 Average of a number of measurements. 
* Vacuolated stages. 
STOMACH 
For this portion of the present paper only the fundus region 
of the stomach has been studied, the development of the gas- 
tric pits (foveolae gastricae) and the gastric or peptic glands 
(glandulae gastricae propriae) being given chief attention. Koelli- 
ker (’61 and ’79) regarded the gastric pits and glands as hollow 
epithelial processes which grow downward into the mesenchyma. 
Laskowsky (’68) confirmed by Schenk (’74) and Brand (77), 
described glands as epithelial in origin, but believed that an up- 
ward growth of the underlying mesenchyma was the active factor 
in their production. Sewall (’79), working on sheep embryos, 
concluded that the first chief and parietal cells were epithelial 
in origin, but were later replaced by others of mesenchymal origin. 
Toldt (’81) in a noteworthy study of the histogenesis of the gas- 
