Frederic T. Lewis and Fred W. Thyng 509 
whereas the cyst has a cavity 0.22 mm. in diameter, equaling that of the 
intestine. 
Two embryos of 24 mm. were examined. In both of these some of the 
intestine within the umbilical cord has been cut away. One series (H. E. 
C. 62) contains 14 diverticula and the other (H. E. C. 64) has 15. There 
are none in the large intestine. 
A partial series from a pig of 32 mm. (H. E. C. 136) includes the large 
intestine to its junction with the ileum. Beyond this point the ileum 
and caecum continue for a short distance and then are both cut away. 
Fic. 4. Section from a pig embryo of 20 mm. (H. E. C. 61, section 228). 
x 50 diams. The loop of the duodenum is cut in two places, Int. Midway 
between these, the Cyst comes in contact with the muscularis, Musc., in the 
following sections. Div., diverticulum. Panc., pancreas. A. mes. sup., arteria 
mesenterica superior. V. p., vena portae. 
Where the caecum joins the colon there is an epithelial proliferation sub- 
dividing the lumen. Here there is a cluster of diverticula, two of which 
are quite distinct. In the remainder of the colon and in the rectum, 
diverticula are absent. The pockets of the small intestine, as seen in wax 
reconstructions, are bean-shaped structures attached to the intestine the 
whole length of their narrow edge. The connection with the intestine is 
laterally compressed, but extends longitudinally through several sections. 
Thus the knobs appear as if modified by the lengthwise growth of the 
intestine. 
