98 AMERICAN WHITE PELICAN. 
ally more forwards, and spreading out, reach the middle line of the 
pouch. The inner fibres have the same origin, and pass in a contrary 
direction, backwards and inwards. From the hyoid bone to the junc- 
tion of the two crura of the mandible, which takes place almost at the 
very tip, there extends a thin band of longitudinal muscular fibres, in 
the centre of which is a cord of elastic tissue. By means of this appa- 
ratus, the sac is contracted, so as to occupy little space. When the 
bill is opened, the crura of the lower mandible separate from each 
other to a considerable extent, by the action of the muscles inserted 
into their base, this depending upon their oblique position, and the sac 
isexpanded. The upper mandible is capable of being moved to a con- 
siderable extent. 
Below the anterior angle of the eye is asmall sac about 5 twelfths 
of an inch in length, with an external aperture of 2 twelfths, and filled 
with a pulpy substance. The nostrils are linear, about 3 twelfths of 
an inch long, and quite concealed by the wrinkles of the skin. The 
aperture of the posterior nares 8 twelfths. The tongue is an extremely 
small, papilliform body, 34 twelfths of an inch long, and 1 twelfth in . 
diameter. The aperture of the glottis is linear, 8 twelfths in length, 
destitute of papilla behind. 
The pharynx is about 23 inches in breadth. The esophagus a, at 
the commencement, or opposite the tongue, has a diameter of about 6 
inches, and contracts until the middle of the neck, where it is 3 
inches in width ; at its entrance into the thorax at b it contracts to 14 
inch, but is dilatable to 3 ches ; at this part, its inner coat is thrown 
into very prominent longitudinal ruge. The structure of the cesopha- 
gus is similar to that of the Loon already described, but its muscular 
coat is much thinner. On entering the thorax, it again expands to a 
diameter of 3 inches. Its length from the glottis, exclusive of the pro- 
ventriculus, is 2 feet. The proventriculus, cd, when not extended, 
has a diameter of 2 inches, its length being 4 inches and 8 twelfths. 
It is marked internally with six longitudinal broad ridges, about half 
an inch in breadth, and separated by grooves; and its cuticular lining 
is 14 twelfths thick, of a compact but soft texture, elevated into tor- 
tuous reticulated ridges. The glandules, which are cylindrical, the 
largest 3 twelfths of an inch long, 3 twelfth in diameter, form a com- 
plete elongated belt. The muscular coat is also very thick. its inner 
a 
