Frederic T. Lewis and Fred W. Thyng 507 
mitotic figure. The nodule is ventral to the vitelline vein and about 
equidistant from the pancreatic tubules and the intestinal epithelium. 
Histologically it has a greater resemblance to the intestine. Another 12 
mm. embryo (H. E. C. 518) shows a single small knob, bridging a clear 
space due to shrinkage between the epithelium and mesenchyma. 
Three 14-mm. embryos were examined. Series 65 shows three small 
buds, and a detached cord of cells seen in seven sections. The cord is 
found between the superior mesenteric artery and the portal vein. One 
of the buds is anterior to it; the other two are posterior, being found 
along the proximal part of the anterior limb of the intestinal loop. 
oe 
ie 
x 
Fie. 3. <A, section through the intestine, Jnt., and diverticulum, Div., in 
a pig embryo of 5.5 mm. (H. E. C. 915, section 232). X 225 diam. B, similar 
section from a human embryo of 13.6 mm. (H. E. C. 839, section 527). * 225 
diams. The diverticulum connects with the intestine in adjacent sections; 
compare with Fig. 5. OC, similar section from a rabbit embryo of 14 days, 
11 mm. (H. E. C. 1327, section 503). .X 150 diams. 
Within the umbilical cord a part of the intestine has been cut off. Series 
66, also a 14-mm. embryo, shows in addition to a small knob, two elon- 
gated pyriform diverticula. The first of these is seen in five 20-u sec- 
tions. It is nearly, but not quite, detached from the intestine. The 
second is also pyriform, its distal diameter being 30 ». Neither of these 
diverticula contains a lumen, yet the nuclei are arranged peripherally, 
as in a simple epithelium. The small knob occurs beyond these diver- 
ticula, on the anterior limb of the intestinal loop. Another 14 mm. 
embryo (H. E. C. 1130) shows two detached epithelial nodules and one 
small pearl or bud. 
42 
