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bk, keel of breastbone; G, g, brain; lr, windpipe; lu, lung; h, heart; sr, gullet; k, crop; dr, glandular stomach; mm, gizzard; d, intestine; n, kidney; hl, ureter; eil, openings of ureter and egg duct into cloaca, kl.

P, pancreas; C, cæca.

Question: Identify each part by means of Fig. 304.

The Internal Organs, or Viscera (Figs. 304 and 305).—The viscera (vis'se-ra), as in most vertebrates, include the food tube and its glands; the lungs, the heart, and larger blood vessels; the kidneys and bladder and the reproductive organs. The lower part, or gullet, is enlarged into a crop. It is largest in grain-eating birds. It is found in the V-shaped depression at the angle of the wishbone, just before the food tube enters the thorax. The food is stored and softened in the crop. From the crop the food passes at intervals into the glandular stomach. Close to this is the muscular stomach, or gizzard. Are the places of entrance and exit on opposite sides of the gizzard, or near together? (Fig. 304.) Is the lining of the gizzard