''Triloculina'' is a genus of

foraminifera Foraminifera ( ; Latin for "hole bearers"; informally called "forams") are unicellular organism, single-celled organisms, members of a phylum or class (biology), class of Rhizarian protists characterized by streaming granular Ectoplasm (cell bio ...

in the order

Miliolida The Miliolida are an order of foraminifera with calcareous, porcelacous tests that are imperforate and commonly have a pseudochitinous lining. Tests are composed of randomly oriented calcite needles that have a high proportion of magnesium along ...

, included in the Quinqueloculininae. The

test Test(s), testing, or TEST may refer to: * Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities Arts and entertainment * ''Test'' (2013 film), an American film * ''Test'' (2014 film) ...

has three chambers, each a half coil in length. Early chambers, at least in the microspheric generation, in

quinqueloculina ''Quinqueloculina'' is a genus of foraminifera in the family Miliolidae. As with all miliolids the test of ''Quinqueloculina'' is composed of imperforate, porcelaneous calcite, often giving them a yellowish tint. As with the Miliolidae, the ...

n arrangement, later becoming triloculine with successive chambers added in planes 120 degrees apart. Only the final three chambers are visible externally. The aperture is terminal, at the end of the final chamber, with a bifid tooth in adult forms. As with the entire order, the test is composed of imperforate, porcelaneous calcite. The Pliocene to Recent '' Cruciloculina'' is very similar, except for having a different aperture, and is a likely derivative.

References

* Joseph A. Cushman, 1950 Foraminifera, their classification and economic use (4th ed) Harvard University Press, Cambridge Mass. *

Alfred R. Loeblich Jr Alfred R. Loeblich Jr (August 15, 1914 – September 9, 1994) was an American micropaleontologist. He was married to Helen Niña Tappan Loeblich and the two co-authored a number of important works on the Foraminifera and related organisms. Biog ...

and HelenTappan, 1964. Sarcodina Chiefly "Thecamoebians" and Foraminiferida;

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology,'' published from 1953–2007 by the Geological Society of America and the University of Kansas, then 2009–present by the University of Kansas Paleontological Institute, is a definitive multi-authore ...

, Part C Protista 2. Geological Society of America and University of Kansas Press. Tubothalamea Foraminifera genera Fossil taxa described in 1826 Extant Jurassic first appearances {{foram-stub