Page:The birds of America, volume 7.djvu/74

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56
COMMON GANNET.


inches, f g, is then recurved for 3 inches, g, h, ascends for 4 inches, h, i, and receives the biliary ducts, then passes toward the spine and forms a curvature. The average diameter of the intestine is 5 twelfths at the upper part, and it gradually contracts to 3 twelfths. The rectum, k, measured to the anus, is 5i inches. It gradually enlarges from 4 to 6j twelfths. The cloaca, m, is globular, 9 twelfths long, S twelfths broad. The cceca are 3 twelfths long, 1^ twelfths broad. The lobes of the liver are extreme- ly unequal, as is always the case when the stomach or the proventriculus is excessively large, the right lobe being 2f inches long, the left 1 inch and 8 twelfths. The gall-bladder, n, is very large, of an oblong form, rounded at both ends, 1 inch and S twelfths long. The trachea is 12 inches long, moderately ossified, round, its diame- ter at the top 7 twelfths, gradually narrowing to 4 twelfths; the rings

124, the lower 4 united. The bronchi are large, their diameter greater than that of the lower part of the trachea; of 25 cartilaginous half-rings. The lateral or contractor muscles of the trachea are of moderate strength; the sterno-tracheals strong; a pair of inferior laryngeal muscles attached to the glandular-looking, yellowish-white bodies inserted upon the membrane between the first and second rings of the bronchi.

The olfactory nerve comes off from the extreme anterior point of the cerebrum, enters a canal in the spongy tissue of the bone, and runs in it close to the septum between the eyes for 10 twelfths of an inch, with a slight curve. It then enters the nasal cavity, which is of an irregular trian- gular form, 1^ inches long at the external or palatal aperture, 10 twelfths in height. The supramaxillary branch of the fifth pair runs along the upper edge of the orbit, and by a canal in the spongy tissue of the bones, enters the great cavity of the upper mandible, keeping nearer its lower surface, and there branching. This cavity appears to have no communication with the nasal; nor has the latter any passage towards the obliterated external nostrils.