508 Intestinal Diverticula in Embryos of the Pig, Rabbit, and Man 
An embryo of 17 mm. (H. E. C. 51) shows nine diverticula, most of 
which have a distinct lumen communicating with that of the intestine. 
They begin below the pancreas and are distributed along the duodenal 
region and anterior limb of the intestinal loop. There are none on the 
posterior limb; within the umbilical cord a portion of the intestine has 
been cut away. Another 17-mm. embryo (H. E. ©. 50) has ten diver- 
ticula and one detached nodule. These are limited to the duodenum and 
small intestine; a portion of the intestine has been cut away. 
A pig of 20 mm. (H. E. C. 59) contains eleven diverticula of the small 
intestine. A part of the intestine has been cut off with the umbilical 
cord. In another pig of 20 mm. (H. E. C. 60) there is a hemispherical 
diverticulum just anterior to the duct of the dorsal pancreas, as shown 
in Fig. 2 (p. 491) of the preceding article in this journal. Beyond the 
dorsal pancreas there is an elongated, unbranched diverticulum .55 mm. 
long and about .07 mm. in diameter, therefore much larger than any of 
those already described. It is shown in the figure as an “ accessory pan- 
creas.” As it crosses the muscle layer of the intestine it is greatly con- 
stricted, suggesting that it may become detached at this point. Beyond 
this “accessory pancreas” there are 18 diverticula along the anterior 
limb of the intestinal loop. In most of these there is a distinct lumen 
leading into the intestine. Similar diverticula occur along the cystic 
duct. There are none along the posterior limb of the intestinal loop; a 
part of the loop within the umbilical cord has been cut away. A third 
specimen of a 20-mm. embryo (H. E. C. 61) has 12 diverticula in that 
part of the small intestine which is preserved. There are none along the 
large intestine. The interesting feature of this embryo is a rather thin- 
walled epithelial cyst with a few rounded outpocketings, found just out- 
side the muscularis of the duodenum, a short distance from the pancreas 
(Fig. 4). The intestine near by presents a solid cylindrical outgrowth 
which extends to the muscularis, but does not penetrate it. Undoubtedly 
this was formerly connected with the cyst, although at present it is not 
directed toward it, and is not where the cyst approaches nearest to the 
muscularis. It appears that after the stalk became detached, the growth 
of the intestine carried it along and changed its direction. The epithe- 
lium of the cyst, which corresponds with the “accessory pancreas” of 
the last specimen, is quite unlike that of the pancreas. The pancreatic 
tubules, about 0.05 mm. in diameter, contain only a minute lumen, 
*Thyng, F. W. Models of the pancreas in embryos of the pig, rabbit, cat, 
and man. Amer. Journ. of Anat., 1908, Vol. 7, p. 489-504. 
