The Foraminifera ("hole bearers", or forams for short), comprise a class of amoeboid protists characterized by branching and anastomozing granulo-reticulose pseudopodia, and a shell, or test, made of various materials and constructed in various forms. They are either planktic, that is live in the water column where they float at various levels, or are benthic and live on or within the seafloor sediment. Most by far are marine, but some few are freshwater or have adapted to brackish conditions.
Foraminifera typically produce a test, or shell, which can have either one or multiple chambers, some becoming quite elaborate in structure. These shells are commonly made of calcium carbonate (CaCO3) or agglutinated sediment particles. About 275,000 species are recognized, both living and fossil. They are usually less than 1 mm in size, but some are much larger, the largest species reaching up to 20 cm.
Read more about Foraminifera: Classification-taxonomy, Living Forams, Biology, Tests, Deep Sea Species, Evolutionary Significance, Uses of Forams, Gallery