A Monograph on the Fossil Reptilia of the Cretaceous FormationsPalæontographical society, 1851 - 118 pages |
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Expressions et termes fréquents
alveolar alveoli anchylosed angle articular end articular surface axis base belonged bird border Bowerbank breadth Cambridge campylodon canal carapace caudal cavity centrum cervical vertebra Chalk of Kent Chalk-pit characters Chelone compressirostris convex coracoid costal plates Cretaceous Crocodile crown Cuvieri dentary dentine distal ditto dorsal vertebra enamel expanded extends extremity fang femur figured foramen fore formation fossil FOSSIL REPTILIA fragment genus groove hinder humerus Ichthyosaurus Iguanodon inches indicates inner side Lacertian length lines Lizards long bone longitudinal ridge lower jaw Maidstone marginal plates median middle Monograph Mosasaurus Mosasaurus Hoffmanni Museum neural arch neural plates neurapophysis obliquely obtuse phalanx Plesiosaurus Polyptychodon posterior present preserved proportions proximal end Pterodactylus Pterodactylus Sedgwickii Pterodactylus suevicus Reptiles ribs Saurian scapula scutes shaft shown shows Side view skull smaller smooth sockets species specimen sternum teeth terminal thick tooth transverse section Turtle ulna Upper Green-sand upper jaw wall wing-finger zygapophyses
Fréquemment cités
Page 59 - Plesiosaurus that Cuvier asserts the structure to have been the most heteroclite, and its characters altogether the most monstrous that have been yet found amid the ruins of a former world. To the head of a lizard it united the teeth of a crocodile, a neck of enormous length, resembling the body of a serpent, a trunk and tail having the proportions of an ordinary quadruped, the ribs of a cameleon, and the paddles of a whale.
Page 106 - Among the specimens lately collected, some, however, were so perfect, that I resolved to avail myself of the obliging offer of Mr. Clift (to whose kindness and liberality I hold myself particularly indebted), to assist me in comparing the fossil teeth with those of the recent Lacertae in the Museum of the Royal College of Surgeons. The result of this examination proved highly satisfactory, for in an Iguana which Mr. Stutchbury had prepared to present to the College, we discovered teeth possessing...
Page 116 - ... use to give an inequality to that surface ; this is the ossified remnant of the pulp, which, being firmer than the surrounding dentine, forms a slight transverse ridge in the middle of the grinding surface. The tooth in this stage has exchanged the functions of an incisor for that of a molar, and is prepared to give the final compression, or comminution, to the coarsely divided vegetable matters. The marginal edge of the incisive condition of the tooth and the median ridge of the molar stage...
Page 115 - U developed on the outer side of the. crown. The marginal serrations which at first sight appear to be simple notches, as in the Iguana, present under a low magnifying power the form of transverse ridges, themselves notched so as to resemble the mammillated margins of the unworn plates of the elephant's grinder. Slight grooves lead from the interspaces of these notches upon the sides of the marginal ridges. These ridges or dentations do not extend beyond the expanded part of the crown ; the longitudinal...
Page 83 - Its lightness, its smoothness, its warmth ; — the disposition of the feathers all inclined backward, the down about their stem, the overlapping of their tips, their different configuration in different parts, not to mention the variety of their colours, constitute a vestment for the body, so beautiful, and so appropriate to the life which the animal is to lead, as that, I think, we should have had no conception of anything equally perfect, if we had never seen it, or can now imagine anything more...
Page 117 - ... they are bent in strong undulations, but afterwards proceed in slight and regular primary curves, or in nearly straight lines to the periphery of the tooth. When viewed in a longitudinal section of the tooth, the concavity of the primary curvature is turned towards the base of the tooth ; the lowest tubes are inclined towards the root, the rest have a general direction at right angles to the axis of the tooth ; the few calcigerous tubes which proceed vertically to the apex are soon worn away,...
Page 115 - In most of the teeth that have hitherto been found three longitudinal ridges traverse the outer surface of the crown, one on each side of the median primitive ridge ; these are separated from each other, and from the serrated margins of the crown, by four wide and smooth longitudinal grooves. The relative width of these grooves varies in different teeth; sometimes a fourth small longitudinal ridge ia developed on the outer side of the crown.
Page 117 - The appearance of interruption in the course of the calcigerous tubes, occasioned by this modification of their secondary branches, is represented by the irregularly dotted tracts in the figure. This modification must contribute, with the medullary canals, though in a minor degree, in producing that inequality of texture and of density in the dentine, which renders the broad and thick tooth of the Iguanodon more efficient as a triturating instrument. The enamel which invests the harder dentine, forming...
Page 117 - ... seen only in a section of the apical part of the crown of an incompletely developed tooth. The secondary undulations of each tooth are regular and very minute. The branches, both primary and secondary, of the calcigerous tubes are sent off from the concave side of the main inflections ; the minute secondary branches are remarkable at certain parts of the tooth for their flexuous ramifications, anastomoses, and dilatations into minute calcigerous cells, which take place along nearly parallel lines...