. Elements of the comparative anatomy of vertebrates. Anatomy, Comparative. VERTEBRAL COLUMN 47 In Snakes and some Lizards (Hatteria, Iguana) extra articular processess {zygosphenes and zygantra) are developed on the neural arches. In Hatteria and the Geckos, small separate ossifications (intercentra, comp. p. 43, 44, 46) are present on the ventral side of the vertebral column between many of the centra. In the caudal region of Lizards anunossified septum remains in the middle of each centrum, so that the tail easily breaks off at these points : when this happens the tail grows again, but prop
. Elements of the comparative anatomy of vertebrates. Anatomy, Comparative. VERTEBRAL COLUMN 47 In Snakes and some Lizards (Hatteria, Iguana) extra articular processess {zygosphenes and zygantra) are developed on the neural arches. In Hatteria and the Geckos, small separate ossifications (intercentra, comp. p. 43, 44, 46) are present on the ventral side of the vertebral column between many of the centra. In the caudal region of Lizards anunossified septum remains in the middle of each centrum, so that the tail easily breaks off at these points : when this happens the tail grows again, but proper vertebrse are not formed. In fossil Reptiles, which both as regards size and number of species usually surpassed the existing representatives of the class, the sacrum often consisted of as many as four or five vertebrse. The following facts will give some idea of the monstrous proportions of these old genera of Reptiles :â Atlantosaurus immanis, a North American Dinosaur, reached a length of. Fio. - Anterior Portion of the Vertebral Column of ^ Ychtni; Crocodile. WK, centrum; Ob, neural arch ; Pn, neural spine ; Ix, intervertebral disc ; Pt,^ transverse process, arising from the base of the arch and articulating witli the rib {B, i?^, S^) at t ; ^, atlas ; «, ventral element, and «â arch of atlas ; o, "pro-atlas"; JEp, axis, articulating with the atlas at h; Po, odontoid process. about 80 feet, and the transverse .diameter of the individual vertebne amounted to 16 inches, while Apatosaiirns laticollis, found in the same strata, possessed cervical vertebrte which reached a diameter of 3J feet. A knowledge of fossil genera of Reptiles is of the greatest interest, as in many groups important points of connection with Birds can be recognised. Birds.âThe vertebral column of Birds corresponds with that of Reptiles not only in its jDhylogenetic relations, but also onto- genetically. In both groups the notochord eventually disappears entirely, and the whole s
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanatomycomparative
