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posterior part of the tube. The anterior part of the 
cesophagus is non-ciliated, but the portion extending from 
about the level of the third diaphragm to the stomach is 
lined by cells which bear short cilia. 
The csophageal glands or pouches are somewhat 
flask-shaped and open into the posterior part of the 
esophagus by a hollow stalk (fig. 23 and 35). They are 
usually greenish in colour, due to the contained secretion, 
but they may also have a pinkish tinge owing to the large 
amount of blood present in the sinuses in their walls. 
These blood sinuses are connected with the lateral 
cesophageal and dorsal vessels. The cavity of each gland 
is sub-divided by twenty to thirty incomplete partitions, 
which, in young specimens or in strongly dilated glands, 
are mere ridges upon the inner wall of the gland, but in 
old ones they are, as a rule, lamelle projecting well 
towards the centre of the pouch (fig. 35). Hach partition 
is produced by infolding of the wall, and is, therefore, 
covered on each face by the epithelial lining of the gland. 
These infoldings of the wall enormously increase the 
secreting surface of the organ. Between these two 
epithelial layers is a blood sinus which is slightly enlarged 
near the free edge of each partition. The pouch is lined 
by cubical cells among which are numerous gland cells. 
The secretion of these glands forms a mucous fluid with a 
neutral re-action. 
The stomach is covered with patches of yellow cells— 
the chlorogogenous tissue—which in front are arranged in 
symmetrical oval areas right and left of the dorsal blood- 
vessel, while more ventrally they are placed in two or 
three less regular series (fig. 23). They are separated 
from one another by blood sinuses. About the level of 
the tenth sete these areas become sub-equal and are 
arranged in a spiral manner, and behind the level of the 
