. The ancient life-history of the earth; a comprehensive outline of the principles and leading facts of palæontological science. Paleontology. Fig. 212.—Toothed Birds {Odotitornithes) of the Cretaceous Rocks of America, a. Left lower jaw of Ichthyornis dispar, slightly enlarged ; b. Left lower jaw of Hesperornis regalis, reduced to nearly one-fourth of the natural size; c, Cervical vertebra oi Ichthyornis dispar, front view, twice the natural size ; d, Side view of the same ; d. Tooth oi Hesper- ortiis regalis, enlarged to twice the natural size. (After Marsh.) but instead of being sunk in dis
. The ancient life-history of the earth; a comprehensive outline of the principles and leading facts of palæontological science. Paleontology. Fig. 212.—Toothed Birds {Odotitornithes) of the Cretaceous Rocks of America, a. Left lower jaw of Ichthyornis dispar, slightly enlarged ; b. Left lower jaw of Hesperornis regalis, reduced to nearly one-fourth of the natural size; c, Cervical vertebra oi Ichthyornis dispar, front view, twice the natural size ; d, Side view of the same ; d. Tooth oi Hesper- ortiis regalis, enlarged to twice the natural size. (After Marsh.) but instead of being sunk in distinct sockets, they are simply implanted in a deep continuous groove in the bony substance of the jaw. The front of the upper jaw does not carry teeth, and was probably encased in a horny beak. The breast-bone is entirely destitute of a central ridge or keel, and the wings are minute and quite rudimentary; so that Hesperornis^ unlike Icht/iyo?'ins, must have been wholly deprived of the power of flight, in this respect approaching the existing Penguins. The tail consists of about twelve vertebrse, of which the last three or four are amalgamated to form a flat terminal mass, there being at the same time clear indications that the tail was capable of up and down movement in a vertical plane, this proba- bly fitting it to serve as a swimming-paddle or rudder. The legs were powerfully constructed, and the feet were adapted to assist the bird in rapid motion through the water. The known remains of Hesperornis regalis prove it to have been a swim- ming and diving bird, of larger dimensions than any of the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Nicholson, Henry Alleyne, 1844-1899. Edinburgh, London, Blackwood
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Keywords: ., bookaut, bookcentury1800, bookdecade1870, booksubjectpaleontology
