Foraminiferans - Protozoan
Foraminiferans are largely benthic marine species. They have multi chambered calcareous tests or shells with numerous pores, hence the name foraminifera or pore bearer. A single large opening allows the cytoplasm to protrude out. The chalk cliffs of Dover England are formed from deep sediments of foraminiferan shells.
Figure: Various types of foraminiferan shells formed chiefly of calcium carbonate. A fossil species -Nummulites is an important contributor to the great limestone deposits in certain parts of the world.