Hesperornis Lower Jaw Small 38×320 Medium 77×640 Large 123×1024 Download Tiff Original 288×2400 | (356.4 KB) Description The lower jaw of the Hesperornis regalis, an ancient bird of the Cretaceous Period. Keywords ancient bird, Cretaceous fossils, dinosaur bones, Hesperornis jaw, Hesperornis regalis, Mesozoic fossils Galleries Bird Anatomy Source: Dana, James D. New Text-Book of Geology (New York: Ivison, Blakeman & Company, 1883) 320
