BLUE HERON. 67 
In this bird, as in most other Herons, the crura of the lower 
mandible are thin, flexible, and elastic, the angle filled by an elastic 
membrane covered by the skin. The tongue is | inch long, sagittate 
at the base, tapering to a point. The roof of the mouth has a median 
prominent ridge, and two lateral lines; the palate is convex ; the pos- 
terior aperture of the nares 10 lines in length. The pharynx may be 
dilated to 13 inch; the cesophagus, which is 12 inches long, is when 
dilated 10 lines in diameter at its upper part, and gradually contracts 
to 7 lines; at the curvature of the neck it lies directly behind, having 
passed down on the left side, along with the trachea. Its walls are 
extremely thin, contrasting in this respect with the cesophagus of the 
Great Northern Diver and other swimming piscivorous birds. The 
proventriculus is 1 inch long, its glandules cylindrical, and extreme- 
ly slender. The stomach seems as if it merely formed a basal sac to 
the cesophagus, its muscles being extremely thin, its tendons cireu- 
lar and half an inch in diameter; cuticular lining soft. ‘The intes- 
tine is long and very narrow, 5 feet 10 inches in length, 2 lines in 
diameter at the upper part, 1} near the rectum, which is 23 inches 
long, with a diameter of 43 lines, and terminates in a nipple-like cecum, 
projecting 3 lines beyond the entrance of the small intestine, but 
having no appearance of the two lateral appendages usually called 
ceca. In this respect, the Blue Heron agrees with others of the 
same family. ‘The cloaca is about an inch in length and breadth. 
The trachea, when extended, is 83 inches long. The rings 170 
in number, are osseous and circular, so that the organ preserves its 
eylindrical form under all circumstances. They are, like those of all 
Herons, of equal breadth on both sides, not broad on one side 
and narrow on the other, as has been represented. The contractor 
muscles are very slender, as are the sterno-tracheal; the former send 
down a slip on each side to the first bronchial ring. The diameter 
of the trachea is 2 lines at the upper part, 13 at the lower. The 
bronchi are short, wide, conical, of about 13 half rings. 
The right lobe of the liver is 21 inches long, the left lobe 13; the 
heart 1} in length, 8 lines broad, of an oblong conical form. The sto- 
mach contained remains of insects and crustaceous animals, together 
with a few seeds. 
