CHAPTER X.

THE ALIMENTARY CANAL, pp. 446-459.

_The solid oesophagus._--OEsophagus originally hollow. Becomes solid during Stage K. _The postanal section of the alimentary tract._--Continuity of neural and alimentary canals. Its discovery by Kowalevsky. The postanal section of gut. Its history in Scyllium. Its disappearance. _The cloaca and anus._--The formation of the cloaca. Its junction with segmental ducts. Abdominal pockets. Anus. _The thyroid body._--Its formation in region of mandibular arch. It becomes solid. Previous investigations. _The pancreas._--Arises as diverticulum from dorsal side of duodenum. Its further growth. Formation of duct. _The liver._--Arises as ventral diverticulum of duodenum. Hepatic cylinders. Comparison with other types. _The subnotochordal rod._--Its separation from dorsal wall of alimentary canal. The section of it in the trunk. In the head. Its disappearance. Views as to its meaning.