A Note on the Microstructures of Three Genera of Late Oligocene Nummulitidae from Kutch

Electron microscopic studies are carried out to examine wall structure, stolon and canal system of Heterostegina, Operculina and Spiroclypeus from the Late Oligocene section of Kutch. Walls are made of preferentially oriented prismatic crystals of calcium carbonate while septa contain randomly oriented polygonal crystals. Heterostegina and Spiroclypeus are characterised by Y-shaped radial stolons in the median plane. Canal system, comprising of marginal, septal and secondary septal canals are described and illustrated.