|
''Clavulina'' is an aggulinated benthic foraminiferan with an elongate test. The early stage is triserial and triangular in section, the later stage uniserial and rectilinear, with angular to rounded section. In some species agglutinated walls have considerable calcareous cement. Septa are secondarily doubled as a result of imperforate floors, which are added as new chambers are formed. Walls contain fine bifurcating canaliculi within, openings of which are sealed internally by an inner organic lining, and externally by the imperforate surface layer of the wall. The aperture is interiomarginal in the early triserial stage, terminal and rounded in the adult. The genus ''Clavulina'' was named by d'Orbigny, 1826. It is included in the textulariid family, Valvulinidae and is cosmopolitan in distribution, with a range extending from the Paleocene to now. ==''References''== *Joseph A. Cushman, 1950. Foraminifera, their classification and economic use. Harvard University Press, Cambridge, Massachusetts. Fourth edition, 1950 * Alfred R. Loeblich Jr and Helen Tappan, 1964. Sarcodina, chiefly "Thecamoebians" and Foraminiferida. Treatise on Invertebrate Paleontology, Part C, Protista 2. Geological Society of America and University of Kansas Press, 1964. *(Valvulinidae ) in Loeblich and Tappan, 1988, Foraminiferal genera and their classification. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Clavulina (foram)」の詳細全文を読む スポンサード リンク
|