GREAT BLACK-BACKED GULL. 637 



fleshy above, horny beneath, rather narrow, deeply channelled, the base 

 emarginate and finely papillate, the tip narrowly rounded. 



The left lobe of the liver is larger than the right, which, however, is 

 more elongated, being 4 inches in length, the other 3 inches ; the gall- 

 bladder oblong, 1 inch 2 twelfths by 7 twelfths. There is a large ac- 

 cumulation of fat under the parietes of the abdomen, and appended to 

 the stomach. 



The oesophagus is 14 inches long ; at the commencement its width 

 is 2^ inches, it then contracts to 1 inch 9 twelfths, at the lower part of 

 the neck enlarges to 2 inches, and towards the proventriculus to 2^ 

 inches ; it then suddenly contracts at the commencement of the sto- 

 mach. This organ is rather small, and of an oblong form, 2^ inches 

 long, 1 inch 9 twelfths broad ; the lateral muscles of moderate size, the 

 inferior prominent, the tendons large and radiated ; the epithelium ex- 

 tremely dense, thick, with strong longitudinal ridges, and of a bright 

 red colour. It contains remains of crabs. The proventricular glands, 

 which are very small, being 1| twelfth in length, and ^ twelfth broad, 

 form a belt 1^ inch in breadth, traversed by very prominent rugae, con- 

 tinuous with those of the stomach. The inner membrane of the oeso- 

 phagus is strongly plaited, and that part is capable of being distended 

 to 3 inches. The intestine is 50 inches long, its greatest width 4| 

 twelfths ; the coeca j inch long, | inch wide, their distance from the 

 extremity 5 inches ; the rectum is 8 twelfths in width, and the cloaca 

 forms a globular dilatation 1| inch in diameter. 



The trachea is 12 inches long ; at the top 7| twelfths wide, gradu- 

 ally contractmg to 4| twelfths, considerably flattened, its rings slightly 

 ossified, 148 in number, of moderate breadth, very thin, contracted in 

 the middle line before and behind ; the last half ring is large, mode- 

 rately arched. In this, as in all the other Gulls, there is a parr of slen- 

 der muscles arising from the sides of the thyroid bone in front, sepa- 

 rating from the trachea, attaching themselves to the subcutaneous cel- 

 lular tissue, and inserted into the furcula. Another pair arise from the 

 same bone in front, spreading over the whole anterior surface of the 

 trachea, then become collected on the sides, send off" a slip to the costal 

 process of the sternum, and continue narrow, to be inserted into the 

 last arched half ring of the trachea ; thus forming what is called a 

 single pair of inferior laryngeal muscles. Bonchi wide, each with 28 

 half rings. 



