Embryonal structures of Miogypsina

Excellent scanning electron micrographs of embryonal structures of bispiral Miogypsina's were made, which solve a number of problems raised by details seen in thin sections. Special attention has been paid to the stolon-system near the second primary auxiliary chamber (ΡΑ-II). From the deuteroconch to the ΡΑ-II two funnel-shaped stolons cross the cylindrical protoconchal stolon on both sides. Once a 'lip' around the protoconchal stolon was discovered, it turned out to exist in nearly all the bispiral specimens.