Foraminifera

Foraminifera ( ; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of Rhizarian protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an external shell called a test of diverse forms and materials. Tests of chitin (found in some simple genera, and Textularia in particular) are believed to be the most primitive type. Most foraminifera are marine, the majority of which live on or within the seafloor sediment (i.e., are benthic, with different sized species playing a role within the macro

Lagenida is an order of benthic foraminiferal rhizaria in which the tests (shells) are monolamellar, with walls composed of optically and ultra-structurally radiate calcite, with the crystallographic c-axes perpendicular to the surface. Lagenids first appear in the Upper Silurian and continue to the Recent. They are currently divided into two superfamilies, the older Robuloidoidea which range from the Upper Silurian to the Lower Cretaceous (Albian) and the younger Nodosarioidea, ranging from the Permian to Recent.

Nodosarioidea is one of two superfamilies making up the foraminiferal order Lagenida. The other being the Robuloidoidea. Of these two Nodosarioidea is the more advanced, as well as being the younger.

thumb|SEM photomicrograph of the test wall of Carterina spiculotesta, showing spicules in the organic matrix of the test. Carterinida is an order of multi-chambered foraminifera within the Globothalamea. Members of this order form hard tests out of thin calcite rods known as spicules, which are held together by a proteinaceous matrix. , the order contains a single family, Carterinidae.

The Rzehakinidae is a family of Lower Cretaceous to recent formaminifera that resemble the calcareous imperforate Miliolidae but which are constructed of finely agglutinated material that veneers an organic base. Tests are with two, or less commonly three, chambers per whorl, which are commonly added in various planes. In form they are generally ovoid.