摘要
光学显微镜下的观察表明(蜒)类的旋壁属于钙质微粒壳类型,对它们的电镜观察揭示了组成旋壁的晶粒的大小、形态和排列方式.对具有致密层和蜂巢层型两层式旋壁的Triticites的电镜研究表明:其致密层由近等轴晶无定向排列而成;蜂巢层由短柱状晶定向排列组成板状复合体,进而组合成管状孔,镶嵌在不定向排列的近等轴品基质中构成.Pseudofusulina的致密层也由近等轴晶不定向排列构成,蜂巢层由粗柱晶定向排列组成纤状复合体,进而形成管状孔,镶嵌在近等轴晶基质中.
Wall structure furnishes one of the most important and reliable criteria for investigation on systematics and classification of foraminifera. Since it provides further information for both phylogeny and classification, the study on wall ultrastructure is of particular importance to the extinct groups of foraminifera, among which the fusulinids are the most important group in the Paleozoic period. Optical microscope observation has demonstrated that the spirotheca of fusulinids is built up of fine calcareous granules. However, our SEM study on the spirotheca of fusulinids has further revealed the size, shape and arrangement pattern of the calcareous crystals consisting of the spirotheca. In Triticites with a two-layered spirotheca, the tectum is composed of isometric crystals showing no preferred orientation in their arrangement, while the keriotheca is composed of brachycolumns of crystals. These brachycolumns are arranged orderly, forming numerous composite slates which constitute the tube-like structures of keriotheca inlaid in the matrix of isometric crystals without preferred orientation. Pseudofusulina has a similar tectum, but its keriotheca is composed of thick-coluinns of cryistals arranged orderly to form composite fibers, which subsequently constitute the tube-like structure inlaid in the matrix of isometric crystals.
出处
《古生物学报》
CAS
CSCD
北大核心
1993年第6期685-692,799-802,共8页
Acta Palaeontologica Sinica
基金
国家青年自然科学基金
