Apertural characteristics of certain unilocular foraminifera: methods of study, nomenclature and taxonomic significance

Abstract. A method is described for cracking open the tests of foraminifera in order to examine in detail the structure of the apertural apparatus; it is used in the examination of certain unilocular forms included in the Nodosariida and the Buliminida. Four distinct types of aperture are described in species which have at some time been included in the genus Oolina. Four new terms, ‘endosolen’, ‘exosolen’, ‘endoanulus’ and ‘endodisc’ are formally proposed to describe structures related to the apertural apparatus in these and other species. The need is indicated for a further revision of the taxonomy of the unilocular Nodosariida and Buliminida which should follow a re-examination of certain holotypes.