منابع مشابه
The Lift Produced by the Heterocercal Tails of Selachii
Selachians have no swimbladders, and are denser than the water in which they live. When swimming horizontally, they must therefore exert a force against gravity. It is generally accepted that in the case of the sharks and dogfish upward forces are generated by the passage of the pectoral fins through the water at a positive angle of attack, and by the action of the heterocercal tail. Harris (19...
متن کاملTomographic Reconstruction of Neopterous Carboniferous Insect Nymphs
Two new polyneopteran insect nymphs from the Montceau-les-Mines Lagerstätte of France are presented. Both are preserved in three dimensions, and are imaged with the aid of X-ray micro-tomography, allowing their morphology to be recovered in unprecedented detail. One-Anebos phrixos gen. et sp. nov.-is of uncertain affinities, and preserves portions of the antennae and eyes, coupled with a heavil...
متن کاملWhen vertebrates invaded land during the Carboniferous
period, they were exposed not only to new ecological opportunities but also to a desiccating environment (Williams and Tieleman, 2002). To maintain cellular water homeostasis in such an environment, natural selection modified the integument of pioneering terrestrial animals, enabling them to reduce water loss through the skin. Nowhere is this modification of the integument more important than f...
متن کاملFire ecology of a Late Carboniferous floodplain, Joggins, Nova Scotia
The facies distribution and palaeobotanical identity of fossil charcoal is described from the Upper Carboniferous (Westphalian A–B) Joggins section, Nova Scotia, in order to examine the fire ecology of early Westphalian floodplains. Three charcoal assemblages are noted. Assemblage (1) consists of channel sandstone bodies, containing beds of calcrete breccia, cordaite logs (up to 3 m long), and ...
متن کاملLepidodendron hickii and Generic Delimitation in Carboniferous Lepidodendrid Lycopods
Lepidodendron hickii is tlie only anatomically preserved Carboniferous lepidodendrid with leaf cushions referable to the compression-based L. aculeatum, the type of Lepidodendron. Historically Lepidodendron has come to encompass several kinds of arborescent lycopods with distinctive vegetative and reproductive morphologies, among which no truly intermediate forms are known. These include totall...
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ژورنال
عنوان ژورنال: Geological Magazine
سال: 1888
ISSN: 0016-7568,1469-5081
DOI: 10.1017/s0016756800173388