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851.
The bivalved arthropod Branchiocaris? yunnanensis Hou, 1987 is redescribed on the basis of new fossil material from the early Cambrian Chengjiang biota, South China. In total, 81 specimens have been examined. The carapace comprises two identical valves, each valve are sub-circular in outline, ranging from 24 mm to 58 mm in length, and from 15 mm to 46 mm in height. The dorsal margin is straight and bears two short cardinal spines. The valve surface is either smooth or ornamented with polygonal reticular structures, which may result from different preservation conditions. Two morphotypes have been recognized based on the presence or absence of a subdorsal swelling of the valve, which is convex dorsolaterally and extends beyond the dorsal margin when it appears. Statistic and ontogenetic analyses show both morphotypes grow isometrically and have the same growth trajectory. Therefore, the two morphotypes are interpreted as dimorphism within the same species. Our results are helpful for investigating the taxonomy and ontogeny of arthropod fossils and suggest that dimorphism might be fairly common in these early arthropods.  相似文献   
852.
正The Moyar-Bhavani Shear Zone(MBSZ)of the South Indian Granulite Terrain(SIGT),a complex continental block formed by the accretion of various crustal units during the Archaean to Neoproterozoic,bear evidences of  相似文献   
853.
In contrast to woody habit with secondary growth, truthful herbaceous habit lacking secondary growth is restricted to angiosperms among seed plants. Although angiosperms might have occurred as early as in the Triassic and herbaceous habit theoretically may have been well adopted by pioneer angiosperms, pre-Cretaceous herbs are missing hitherto, leaving the origin of herbs and evolution of herbaceous angiosperms mysterious. Here we report Juraherba bodae gen. et sp. nov, a whole plant herbaceous angiosperm, from the Middle Jurassic (>164 Ma) at Daohugou Village, Inner Mongolia, China, a fossil Lagerst?tten that is worldwide famous for various fossil finds. The angiospermous affinity of Juraherba is ensured by its enclosed ovules/seeds. The plant is small but complete, with physically connected hairy root, stem, leaves, and fructifications. The Middle Jurassic age recommends Juraherba as the earliest record of herbaceous seed plants, demanding a refresh look at the evolutionary history of angiosperms.  相似文献   
854.
Khare BN  Sagan C  Ogino H  Nagy B  Er C  Schram KH  Arakawa ET 《Icarus》1986,68(1):176-184
An organic heteropolymer (Titan tholin) was produced by continuous dc discharge through a 0.9 N2/0.1 CH4 gas mixture at 0.2 mbar pressure, roughly simulating the cloudtop atmosphere of Titan. Treatment of this tholin with 6N HCl yielded 16 amino acids by gas chromatography after derivatization of N-trifluroacetyl isopropyl esters on two different capillary columns. Identifications were confirmed by GC/MS. Glycine, aspartic acid, and alpha- and beta-alanine were produced in greatest abundance; the total yield of amino acids was approximately 10(-2), approximately equal to the yield of urea. The presence of "nonbiological" amino acids, the absence of serine, and the fact that the amino acids are racemic within experimental error together indicate that these molecules are not due to microbial or other contamination, but are derived from the tholin. In addition to the HCN, HC2CN, and (CN)2 found by Voyager, nitriles and aminonitriles should be sought in the Titanian atmosphere and, eventually, amino acids on the surface. These results suggest that episodes of liquid water in the past or future of Titan might lead to major further steps in prebiological organic chemistry on that body.  相似文献   
855.
作者使用威斯特波克射电望远镜在610兆赫频率上对古代东方天文学家观测到的“客星”的七个视场区(1~o.5×1~o.5)进行了射电遗迹的巡天探测,结果没有发现弥漫射电辐射。本文给出了在这些视场区中的分立射电源的表,表中列出作者提出的这些射电源|b|<15°以內的光学证认。  相似文献   
856.
INTRODUCTION. I was appointed to accompany Dr. J. G. Andersson to take a trip incentral Shantung. especially in Men Yin (蒙阴) and Lai Wu (莱芜),valleys,for the purpose of collecting fossils and observing the post-Palaeozoic forma-tions. We came back to Peking in December, 1922. The conclusion  相似文献   
857.
C.Y.HSIEH. 《地质学报》1923,2(Z2):113-115
In spite of the immense records of meteoric fall kept in many ofthe Chinese books, specimens of real meteorite were very seldom found.Perhaps the first found of iron meteorite was from Inner Mongolia described  相似文献   
858.
1. The different geological formations and their ecouomie sigmficances. (a)Alluvium (b)Loess (c)Red beds (d)Upper coal series and Sandstone formations (e)Lower coal series (f)Metamorphic series  相似文献   
859.
That the geology cf the Chinese coal fields is becoming better and better known is evidenced by the numerous publications put out from tirne to time by the different investigators, especially by the members of the National Geological Survey in Peking. But little attention seems to have been paid to the microscopical  相似文献   
860.
HONG KONG CELTS.     
INTRODUCTION This article has been written as an explanatory note to an exhibit of stone artifacts sent to the meeting of the Society. It is also hoped that for people in South China it will be an introduction to the prehistoric archeology  相似文献   
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