Foraminifera (, Latin meaning
hole bearers, informally called "
forams") are members of a phylum or class of
amoeboid protists characterized by streaming granular ectoplasm that among other things is used for catching food, and commonly by an external shell or "
test" made of various materials and constructed in diverse forms. All but perhaps a very few are aquatic and most are marine, the majority of which live on or within the seafloor sediment (i.e., are
benthic) while a smaller variety are floaters in the water column at various depths (i.e., are
planktonic). A few are known from freshwater or brackish conditions and some soil species have been identified through molecular analysis of small subunit
ribosomal DNA.