106 
.AMERICAN ANHINGA. 
The oesophagus, a b, is IT inches long, exceedingly delicate and dilatable, 
with external longitudinal fibres, the transverse fibres becoming stronger 
towards the lower parts. Its diameter when moderately dilated is If inches 
at the top, 1 inch farther down, at its entrance into the thorax, 9 twelfths, 
and finally inches : but it may be dilated to a much greater extent. The 
proventricular glands, instead of forming a belt at the lower part of the oeso- 
phagus, are placed on the right side in the form of a globular sac, about an inch 
in diameter, communicating with the oesophagus, b, and stomach, d. For 
two inches of the lower part of the oesophagus, b, or at that part usually 
occupied by the proventriculus, the transverse muscular fibres are enlarged, 
