A GLOBIGERINA. d'Orbigny, a genus of Perforate Foraminifera (q.v.) of pelagic habit, and formed of a conical spiral aggregate of spheroidal chambers with a crescentic mouth. The shells accumulate at the bottom of moderately deep seas to form " Globigerina ooze " and are preserved thus in the chalk. Hastigerina only differs in the " flat " or nautiloid spiral.