AMERICAN WHITE PELICAN. 



29 



oblique position, and the sac is expanded. The upper mandible is capable 

 of being moved to a considerable extent. 



Below the anterior angle of the eye is a small 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 S twelfths. The tongue is an extremely small, papilliform 

 body, 3^ twelfths of an inch long, and 1 twelfth in diameter. The aperture 

 of the glottis is linear, S twelfths in length, destitute of papillae behind. 



The pharynx is about 2j inches in breadth. The oesophagus 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 1|- inches, but is dilatable 

 to 3 inches; at this part, its inner 

 coat is thrown into very prominent 

 longitudinal rugae. The structure of 

 the oesophagus 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 proven- 

 triculus, c d, when not extended, has 

 a diameter of 2 inches, its length 

 being 4 inches and S twelfths. It is 

 marked internally with six longitu- 

 dinal broad ridges, about half an inch 

 in breadth, and separated by grooves; 

 and its cuticular lining is 1^ twelfths 

 thick, of a compact but soft texture, 

 elevated into tortuous reticulated 

 ridges. The glandules, which are 

 cylindrical, the largest 3 twelfths of 

 an inch long, |- twelfth in diameter, 

 form a complete elongated belt. The 

 muscular coat is also very thick, its 

 inner layer composed of transverse, 

 its outer of longitudinal fibres, and 

 the greatest thickness of the walls of 



