. The Auk. Birds. V°1'l9l9Xyi] Wetmore, The Palate in Icteridce. 191 Museum, there have been available suitable specimens represent- ing all of the leading genera with the exception of Clypeicterus, Ocyalus, Lampropsar and Macragelceus. In all, one hundred and thirteen species belonging to thirty-one genera have been examined. Study of skins of the genus Quiscalus shows that the palatal keel is developed as a compressed projection from the roof of the mouth, slightly behind the center of the commissure (Fig. 1). Viewed. Fig. 1. Head of Quiscalus guiscula aeneus. a Palatal keel (about natural a
. The Auk. Birds. V°1'l9l9Xyi] Wetmore, The Palate in Icteridce. 191 Museum, there have been available suitable specimens represent- ing all of the leading genera with the exception of Clypeicterus, Ocyalus, Lampropsar and Macragelceus. In all, one hundred and thirteen species belonging to thirty-one genera have been examined. Study of skins of the genus Quiscalus shows that the palatal keel is developed as a compressed projection from the roof of the mouth, slightly behind the center of the commissure (Fig. 1). Viewed. Fig. 1. Head of Quiscalus guiscula aeneus. a Palatal keel (about natural aize.) from the side it is truncated in front, forming an angular projection that has a tendency to become toothed at the tip. Posteriorly it lowers to merge finally into the level of the palate. The anterior margin is sharp, and the posterior portion is thicker and stronger. The entire ridge is developed as a fold in the horny sheathing of the palate, and the surface of the premaxilla underneath is smooth and flat with no indication of a bony ridge to support the keel. From the examination of museum skins it appears that the palatal ridge begins to develop in juvenile birds a short time before they leave the nest, at a stage when the body is well covered with feathers, and the incoming tail feathers have attained a length of 20 to 25 millimeters. In such birds the keel appears as a very slightly raised ridge that forms a distinct line on the palate. The bill at this time has reached about three-fourths of the length attained when the bird is adult, so that the beginning of this ridge appears to be located far forward, though it occupies the same position in relation to the external nasal opening that the fully developed keel does in the adult. In the dried skins the ridge is somewhat indistinct, but it is possible that it may be more readily apparent in living or recently killed Please note that these images are extracted from scanned page images that may have been
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbirds, bookyear1884
