. Elements of geology : a text-book for colleges and for the general reader. Geology. TRIASSIC PERIOD. 419 /$h animals by the discovery in Triassic strata of certain tracks made by a clumsy-footed animal (Fig. 619), which was at first mistaken for a mammal and called Cheirotherium (hand-beast). Its true nature was made known by Prof. Owen, who called it Labyrinthodont. The Anomodonts (lawless-toothed) had jaws covered with horn, like tor- toises and birds, sometimes toothless, as in Oudenodon (Fig. 621), and some- times with two great canines only, as in Dicynodon (Fig. 620). These rep- tiles
. Elements of geology : a text-book for colleges and for the general reader. Geology. TRIASSIC PERIOD. 419 /$h animals by the discovery in Triassic strata of certain tracks made by a clumsy-footed animal (Fig. 619), which was at first mistaken for a mammal and called Cheirotherium (hand-beast). Its true nature was made known by Prof. Owen, who called it Labyrinthodont. The Anomodonts (lawless-toothed) had jaws covered with horn, like tor- toises and birds, sometimes toothless, as in Oudenodon (Fig. 621), and some- times with two great canines only, as in Dicynodon (Fig. 620). These rep- tiles were of great size. The head of the Dicynodon tigriceps was twenty inches long and eighteen inches wide. The RhyncosaursYi&dL strongly-hooked, horny beaks, like that of a parrot (Fig. 623 a). The curious reptile Spheno- don, or Hatteria, of New Zealand (Fig. 623 b), is the nearest living A Fig. 617. Fig. 618. Figs. 61' 618.—Tkiassic ~REFTfLBS—Labi/nnthodonts: 617. Tooth of Labyrinthodon, natural size. 618. Section of same enlarged, showing structure. The Theriodonts (beast-toothed) are so called on account of the resemblance of their teeth to those of the lowest and earliest mammals. The following are the main points of resemblance: 1. The teeth are in three sets, viz., incisors, canines, and molars. 2. The canines are much larger than the others, and separated from them by a wide space (diastema). 3. The molars (jaw-teeth) are in many cases not conical, like reptilian teeth, but have commenced to develop cusps (Fig. 624) like those of mammals, especially the earliest Mesozoic mammals. (Compare this figure with Fig. 711, p. 449.) The canines of some of these Theriodonts have been found five and six inches long. A large. 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 LeConte, Joseph, 1823-1901
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectgeology, bookyear1892
