Page:The birds of America, volume 7.djvu/251

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THE GREAT BLACK-BACKED GULL.
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brown, the feet as in the adult. The head and neck are greyish-white, streaked with pale brownish-grey; the upper parts mottled with brownish- black, brownish-grey, and dull white, the rump paler. The primary quills blackish-brown, slightly tipped with brownish-white; the tail-feathers white, with a large brownish-black patch towards the end, larger on the middle feathers, which are also barred towards the base with dusky. The lower parts are greyish-white, the sides and lower tail-coverts obscurely mottled with greyish-brown.

Male, from Dr. T. M. Brewer. The mouth is of moderate width, its breadth being 1 inch 9 twelfths; the palate flat, with two very prominent papillate ridges, and four series of intervening papillae; on the upper man- dible beneath are five ridges, and the horny edges are prominent and thin, but very strong; the posterior aperture of the nares linear, 1 inch 9 twelfths long. The tongue is 2 inches 2 twelfths in length, 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 accumulation 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 stomach. 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 extremely dense, thick, with strong longi- tudinal ridges, and of a bright red colour. It contains remains of crabs. The proventricular glands, which are very small, being 1^ twelfths in length, and twelfth broad, form a belt % inches in breadth, traversed by very prominent ruga?, continuous with those of the stomach. The inner membrane of the oesophagus is strongly plaited, and that part is capable of being distended to 3 inches. The intestine is 50 inches long, its greatest width A twelfths; the cceca 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^ inches in diameter.

The trachea is- 12 inches long; at the top 7J twelfths wide, gradually con- tracting 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, moderately arched. In this, as in all the other Gulls, there is a pair of slender muscles arising from the