Textural Observations on Some Living Species of Planktonic Foraminifera

Abstract

Wall textures of 11 species of spinose and quasi-spinose planktonic foraminifera collected in plankton tows from the North and Equatorial Atlantic have been studied with the scanning electron microscope. Illustrations and descriptions of these textures are given herein. During the ontogeny of the individual the chamber wall thickens and the texture is modified in various forms. Thickening occurs by the addition of sheet-like laminations and clustering of crystallites that generally develop into ridges among the pores. Patterns of textural development vary among species, but there are some common trends.