556 Franklin P. Johnson. 
are four large primary folds. Of these the dorsal and ventral 
(left and right respectively in the lower part of the cesophagus) 
develop first; the left and right (ventral and dorsal below) develop 
soon afterward. Smaller secondary folds, variable in number, 
appear later at the bases of the primary folds. In the lower 
part of the cesophagus both primary and secondary folds are 
twisted through an are of about 90 degrees in the direction of the 
hands of a clock. It is probable that this twisting is due to the 
early rotation of the stomach. 
4. Areas of ciliated cells are found in the epithelium of the 
cesophagus in embryos ranging from 55 mm. to birth. There is 
both an actual and a relative increase in the amount of surface 
covered by ciliated cells in embryos up to 187 mm. At birth 
these areas are relatively smaller. Ciliated cells are absent in 
the cesophagus of a child of 14 days (seven months premature 
birth). 
5. Cardiac glands are found in both the upper and lower ends 
of the oesophagus. They begin as small areas of glandular cells, 
which were first seen in an embryo of 78 mm. Later these areas 
evaginate, forming small pockets and grooves. Later, a number 
of tubular glands grow out from these pockets. 
6. Qisophageal glands were first observed in an embryo of 
240 mm. They grow out from the epithelium through the mus- 
cularis mucosae and lie in the submucosa. In contradistinction 
to the cardiac glands, their glandular epithelium does not develop 
until after the excretory ducts are formed. At birth the end pieces 
of the glands have begun to branch. 
Stomach 
1. <A few vacuoles, similar to those of the cesophagus, are found 
in corresponding stages in the stomach. 
2. At16mm., the heretofore smooth epithelium shows a num- 
ber of pit-like depressions, the first appearances of the gastric 
pits. These rapidly increase in number and many become elon- 
gated to form grooves. 
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