Frederic T. Lewis and Fred W. Thyng 513 
has been studied by Tandler* is independent of the formation of the 
diverticula. Below the duodenal pocket, indications of diverticula may 
be observed at twelve places along the small intestine. There are transi- 
tions between well defined diverticula and slight irregularities of the 
epithelium which may be without significance. 
Series 181, an embryo of 23.0 mm., shows well-developed pockets. 
Several of the sections are misplaced and the counting of the diverticula 
is somewhat difficult, but there appear to be 33 along the small intestine. 
There are none in connection with the vermiform process or large 
intestine. 
An embryo measuring 22.0 mm. (H. E. C. 851) is obviously more 
advanced than the preceding embryo of 23.0 mm.; its shorter length is 
due to greater curvature of the back and flexion of the head. The epi- 
thelium in the proximal part of the small intestine is greatly folded and 
has shrunken from the mesenchyma, so that diverticula would be difficult 
to recognize. Within the umbilical cord the intestine is well preserved 
and presents 48 pockets, generally flask-shaped. Hach has a lumen con- 
necting with that of the intestine. There is a well-developed pocket 17 
12- sections above the large intestine, and a slight one only six sections 
above it, but throughout the large intestine and vermiform process no 
pocket occurs. The lining of the large intestine is generally smooth, 
except in the rectal region; that of the small intestine is considerably 
folded. 
In the largest series available (H. E. C. 292), from an embryo of 32 
mm., the large intestine was carefully examined. The rectum showed 
highly developed folds among which a pocket might be hard to detect. 
None was found. The upper portion of the large intestine showed usu- 
ally a smooth reniform or trifoliate lumen, and was without a single 
pocket. There were none in the vermiform process, but they occurred in 
the ileum near its termination. 
The preceding study of human embryos shows that solid knob-like 
diverticula of the intestine may occur before the formation of the dorsal 
pancreas, but that older embryos, from 7.5 to 10.0 mm., may be without 
them. An embryo of 13.6 mm. shows one prominent duodenal pocket, 
with indications of 12 others along the small intestine. At 23 mm., 33 
pockets were counted, and in an older embryo there were 48. In these, 
and in an embryo of 32 mm., no diverticula were found along the large 
intestine and vermiform process. 
’Tandler, J. Zur Entwicklungsgeschichte des menschlichen Duodenum. 
Morph. Jahrb., 1900, Vol. 29, p. 187-216. 
