THE GREAT WHITE HERON. 121 



covering nearly the entire surface of the proventriculus and stomach, and 

 extending under the intestine, being in one place 9 twelfths thick. 



On entering the thorax the oesophagus immediately enlarges to 2^ inches, 

 and gradually increases to 3, which is the greatest breadth of the proven- 

 triculus, a b c. The stomach, c p e, is a very large round sac, 3 inches in 

 width, a little compressed, with roundish tendons, p, f inch in diameter; its 

 muscular coat extremely thin, and formed of very slender fasciculi; the 

 inner coat soft and smooth. The proventricular glands form a complete belt, 

 1^ inches in breadth, at the upper part of which are numerous irregularly 

 dispersed very large apertures of mucous crypts. The pyloric lobe of the 

 stomach, e, is globular, 9 twelfths in diameter. The aperture of the pylorus 

 lj twelfths in diameter, without valve. The intestine, efj k, doubles in 

 the usual manner, to form the duodenum, efg, at the distance of 6 inches, 

 then proceeds to the right lobe of the liver, bends backward, and is con- 

 voluted, with IS turns, terminating in the rectum above the proventriculus; 

 its length 7 feet 10 inches; the width of the duodenum 3^ twelfths, that of 

 the rest of the intestine pretty uniformly 3 twelfths, a little narrowed 

 towards the rectum, which is 5| twelfths long, and at its commencement 

 forms a single coecum, ^ inch long, and 3 twelfths in width. The average 

 width of the rectum is 5 twelfths, and it terminates in a globular cloaca, j k, 

 1 inch 10 twelfths in diameter. 



Trachea 22 inches long, considerably flattened, 5 twelfths in breadth at 

 the upper part, A\ twelfths at the middle, and lastly contracting to 3|- 

 twelfths. The rings cartilaginous, 270, the last 4 dimidiate. The right 

 bronchus has 25 rings, the left 28; they are wide and compressed. There 

 is a pair of cleido-tracheal muscles, passing from the thyroid bone to near 

 the middle of the furcula. The lateral muscles are thin and slender at the 

 upper part, at the lower part thicker and expanded over the whole surface 

 before and behind; the anterior part gives off the sterno-tracheal, at the 

 distance of 9 twelfths from the last ring, and the posterior part passes in the 

 form of a compact slip, to the last half ring. 



Vol. VI. 17 



