Sarcomastigophora

Os Sarcomastigophora:

The phylum Sarcomastigophora includes na unwieldy, and probably polyphyletic assortment of protozoa, united by possesion of pseudopodia (the amoebae), one or more flagellla (the flagellates). Or both these kinds of locomotory organelle. Cilia are developed only in the parasitic opalinids. With the exception of some foraminifera, members of the phylum have only one kind of nucleus, a feature which distinguishes them from the ciliates. Reproduction is usually by binary fission, less commonly by multiple fission or budding. Sexual reproduction normally involves the fusion of gametes from different individuals to form a zygote (syngamy). Most sarcomastigophorans are free-living but a few are parasitic. Some mastigophorans (flagellates) form colonies. The sarcodinans (amoebae) may be naked or possess a secreted or agglutinated shell. In their size, members of the phylum span five orders of magnitude from tiny flagellates and amoebae a few microns long to the giant xenophyophores, some species of the which construct tests up to 25 cm across.
Foraminífera occur in all marine environments and a few species penetrate into brackish or fresh water. They are normally most common in fine-grained sediments. In general, they are less abundant in coarse sands without some silt and clay than in muds, presumably mecause food is scarcer. Many sediment-dwelling foraminifera live on or near the sediment surface where the nutrients are concentrated and the pore-water well aerated. Some species occur infaunally, usually in the upper few centimeters of sediment but sometimes deeper, while others mey be both infaunal and epifaunal.