AMERICAN SWAN. 
233 
outer lamellae only 22. Bill along the ridge 4^ inches, from the angle of the 
eye to the tip 4f§; lower mandible along the edge 3^; depth of bill at the 
angle of the mouth 1 T 9 2 , its breadth at the nostrils l x 4 2 , near the end 
The roof of the mouth is deeply concave, with a medial prominent line, on 
which is a series of hard tubercles. The width of the mouth is 1 inch 5 
twelfths. The eyes are very small, their diameter being 5 twelfths, the 
aperture of the ear 4 twelfths. The internal cells are of vast size; the right 
thoracic being 4 inches long, the right abdominal 6 inches, the right hepatic 
the left hepatic 4, the left abdominal 34, the left thoracic 3. The heart 
is proportionally of large size, being 3 inches 2 twelfths in length, 2 inches 
10 twelfths in breadth. The oesophagus, Fig. 1, a b c, is 2 feet 2 inches 
long, much narrower than the intestine, its average diameter being only 4 
twelfths, but at the lower part of the neck it dilates to 8 twelfths ; on 
entering the thorax, it passes obliquely to the left side, and the proven- 
triculus, b c, has a diameter of 1 inch 2 twelfths. The inner coat of the 
oesophagus is thrown into strong longitudinal rugae, and the muscular coat 
consists of two layers, the outer composed of longitudinal, the inner of 
transverse fibres. The stomach, d e f g, is obliquely situated on the left 
side, and is an extremely developed muscular gizzard, of an elliptical form, 
its length being 2 inches 
6 twelfths, its breadth 3 
inches 10 twelfths. The 
right lateral muscle, g, is 1 
inch 9 twelfths thick, the 
left, e, 1 inch 4 twelfths. In 
the stomach is a large mass 
of very fine quartz sand, 
and a great number of ger- 
minating seeds of an ellip- 
tical form, some about 5 
twelfths long, and of a 
brownish-yellow colour, to- 
gether with shoots of Sali- 
cornia. The proventriculus 
is turgid with the latter. 
Its glands are extremely 
numerous, of a cylindrical 
form, about 3 twelfths in 
length. The epithelium, or 
inner coat of the stomach, 
is thick and tough, the two 
Vol. YI. 
32 
