. The structure and classification of birds . es stronger. Below the shoulder it bifur-cates and becomes suddenly weak; below this point the wholedorsal region is covered with a weak and diffused feathering,which is especially weak over the head of the femur. In the C. J. Temminck, Sistoire Natii/relle Oinirale des Pigeons et des et Paris, 1813-1815. X 306 STRUOTUEE AND CLASSIFICATION OF BIRDS middle line posteriorly the dorsal tract is again lumbar region is also strongly feathered, and the thigh iscovered by a strong tract which ends very abruptly below. T
. The structure and classification of birds . es stronger. Below the shoulder it bifur-cates and becomes suddenly weak; below this point the wholedorsal region is covered with a weak and diffused feathering,which is especially weak over the head of the femur. In the C. J. Temminck, Sistoire Natii/relle Oinirale des Pigeons et des et Paris, 1813-1815. X 306 STRUOTUEE AND CLASSIFICATION OF BIRDS middle line posteriorly the dorsal tract is again lumbar region is also strongly feathered, and the thigh iscovered by a strong tract which ends very abruptly below. The ventral tract is much weaker, and on the neckgradually merges into the lateral space which extends froma short way below the head to the shoulder. Below this theventral tract is still weaker, and does not bifurcate until theupper end of the carina sterni. The median apterion isoblong and narrow, and reaches the cloacal aperture. Inthe abdominal region the two tracts get stronger. Thepterylosis of Columba livia as figured by Nitzsch hardly. i 1 III II I I M ^1 JI -. J Gizzards op, a, PHlopus jainhu,b, Treron calva (after Garkod). Fio. 155.—a, Gizzard of Garpophagalatrans. b, One of Hoent Tuber-cles IN Section. (After Gakkod.) differs, and is typical of the pigeons in general; there is nodown. All pigeons have a well-developed crop, the presence ofwhich organ is presumably related to their fruit- and grain-eating mode of life. In Garpophaga, a fruit-eating pigeon, the gizzard is veryweak; but in other pigeons this organ is very strong, itswalls being even ossified in Caloenas nicoharica} In Ptilopusa cross section of the gizzard has the peculiar form shownin the accompanying drawing, where it is compared with a Vekeeaux and Des Mubs describe an exaggeration like this in PhosnmMnagoUath, where also the tubercles are ossified (Bev. Mag. Zodl. 1862, p. 138).See also Flower, On the Structure of the Gizzard of the Nicobar Pigeon,P. Z. 8. 1860, p. 330. COLUMB^ 307 pigeon showing a
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbirds, bookyear1898
