From Marine Biodiversity Wiki
(= foraminiferans) phylum of mainly marine unicellular protists (classified as protozoans of class Sarcodina in older zoological classifications), having a highly vacuolated outer layer of cytoplasm and a calcareous, siliceous or composite shell through which project fine pseudopodia. Chalk is largely composed of foraminiferan shells and they are also major components of many deep-sea oozes..
- Lawrence, E. (2005). Henderson’s dictionary of biology. Pearson Education Limited, 13th ed., Harlow. 748 p.