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allied ambulacral animal aperture appear arms attached base beaks become belong body branches calcareous calyx canal Carboniferous carry chamber characters closely commonly completely composed comprises condition consists corallites corallum corals Cretaceous deposits developed Devonian distinct divided division dorsal ends enlarged entire existing external fact five formation forms fossil four front genera genus grooves hand included internal Jurassic known lateral layer less limestones living lower margin marked minute mouth natural occur Ordovician organisms Original outer pair perforated period placed plates pores portion possess present principal radial range recent referred regarded remains represented resembles rocks rounded rows separated septa shell short showing side Silurian similar simple single skeleton sometimes species spicules spiral structure surface Tertiary thin transverse tubes types Upper usually valve ventral wall wide
עמוד i - NICHOLSON. A Manual of Zoology, for the use of Students. With a General Introduction on the Principles of Zoology. By HENRY ALLEYNE NICHOLSON, MD, D.Sc., FLS, FGS, Regius Professor of Natural History in the University of Aberdeen.
עמוד 134 - ... a thickness of several thousand feet. It may be said to play a far more conspicuous part than any other Tertiary group in the solid framework of the earth's crust, whether in Europe, Asia, or Africa. It occurs in Algeria and Morocco, and has been traced from Egypt, where it was largely quarried of old for the building of the Pyramids, into Asia Minor, and across Persia by Bagdad to the mouths of the Indus. It has been observed...
עמוד 134 - The nummulitic formation, with its characteristic fossils, plays a far more conspicuous part than any other tertiary group in the solid framework of the earth's crust, whether in Europe, Asia, or Africa. It often attains a thickness of many thousand feet, and extends from the Alps to the Carpathians, and is in full force in the north of Africa, as, for example, in Algeria and Morocco. It has also been traced from Egypt, where it was largely quarried of old for the building of the Pyramids, into Asia...
עמוד 672 - Dorsal valve with a loop consisting of two delicate riband-like lamellae, which extend about one-half the length. These lamellae at first curve gently outwards, and then approach each other gradually, until at their lower extremities they meet at an acute angle ; then becoming united, they are reflected backwards towards the beak in what appears to be a thin flat vertical plate.
עמוד 120 - ... surface, those of the last convolution only on the inferior or apertural side, sometimes one face being more convex, sometimes the other. Aberrant forms evolute, outspread, acervuline or irregular. Some of the higher modifications with double chamber-walls, supplemental skeleton, and a system of canals.
עמוד 102 - It cannot be doubted, therefore, that palaeontology has, so far, to a large extent, failed to bring forward the numerous and closely graduated series of intermediate forms which must at one time have existed, supposing ' natural selection ' to be the sole agent in the origination of new species. The absence of a sufficient number of such transitional forms, and the insufficient connection between such as are known to exist, may doubtless be in part explained by the known ' imperfection of the geological...
עמוד 485 - As might be expected, the markings above referred to, when in relief, occur on the under sides of the beds. A few instances may, however, be found where they exist on the upper surfaces. On careful consideration of these raised impressions, I have arrived at the conclusion that they have been left by denudation of the surrounding material, just as footprints on dry snow sometimes remain in relief after the surrounding loose snow has been drifted away by the wind ; the portion consolidated by pressure...
עמוד 361 - SeaUrchins, the Star-Fishes, the Brittle-Stars, the Sea-Cucumbers, &c. They are furnished with an exoskeleton of carbonate of lime, and are well preserved in a fossil state. " Each plate, spine, and joint are mineralogically and optically, as it were, made out of a single crystal of calcite, having its principal axis perpendicular to the plane of the plate, or parallel to the axis of a spine or joint, the growth being from first to last in perfect crystalline continuity.
עמוד 134 - It often attains a thickness of many thousand feet, and extends from the Alps to the Carpathians, and is in full force in the north of Africa, as, for example, in Algeria and Morocco. It has been traced from Egypt — where it was largely quarried of old for the building of the pyramids — into Asia Minor, and across Persia, by Bagdad, to the mouth of the Indus.
עמוד 488 - On Annelid Jaws from the Cambro-Silurian, Silurian, and Devonian Formations in Canada, and from the Lower Carboniferous in Scotland. Quart. Journ. Geol. Soc., Vol. xxxv. (1879), p. 370. GJ Hinde. On Annelid Jaws from the Wenlock and Ludlow Formations of the West of England.