1909-10.] Nervous Mechanism of Alimentary Canal of the Bird. 341 
vagus fibres were found to be abundant in the stomach, while a few 
vagus fibres were found in the first portion of the small intestine. The 
cluster of sympathetic nerve cells described at the fifth day as lying at the 
point of entrance of the vagus to the stomach wall was not nearly so 
prominent, the cells having become, in all probability, dispersed in the 
stomach wall. Slight chains of cells were seen at several points connecting 
the two plexiform layers of nerve tissue in the gut wall. In the lower 
intestine a fairly well-developed plexus was seen lying deeply in the wall 
of the gut, hut the cylindrical band of nerve cells on the dorsal side of the 
gut, i.e. the intestinal nerve of Remak, was by far the more prominent 
structure. It was found to extend higher up the gut than at the fifth 
Fig. 2. — A, posterior root ; B, anterior root ; C, sympathetic ganglion. 
day, but otherwise presented no new features. At this stage an unsatis- 
factory and doubtful connection appeared to exist between it and the 
sympathetic nerve elements in the pelvic plexus. 
At this stage of development the growth of the various portions of the 
sympathetic chain was marked not only by an increase in number of the 
nerve elements but by the better staining of its parts. 
At the seventh day of incubation the sympathetic chain and its 
•connection with the spinal nerves were well developed. A complete and 
well-developed connection existed between the sympathetic chain and the 
intestine. The plexus in front of the aorta in the abdominal region was 
exceedingly well marked, while its reaction to the silver stain was consider- 
ably improved (PI. II. fig. 2). At the lower level of the stomach this 
pre-aortic plexus showed comparatively large clusters of cells, which were 
apparently the precursors of abdominal ganglia in the adult. From the 
