Heterospira, a new foraminiferal genus from the Tertiary of Borneo

In thinsections of tertiary limestones from Borneo I studied numerous specimens of a new genus of foraminifera showing an interesting and rather complicated structure. The material belongs to the Geological Survey of the Netherlands East Indies („Dienst van den Mijnbouw in Nederlandsch Indië”) at Bandoeng, Java. Syntypes 1) are in the palaeontological collection of the „Instituut voor Mijnbouwkunde” at Delft. My thanks are due to Mr. A.C. de Jongh, formerly director of the geological survey in the East Indies, who kindly lent me these rocks.