The
Soritacea are a group of
miliolid benthic foraminifera with porcellaneous tests. They take on a variety of growth forms but typically have many chambers. Some soritids can grow over a centimeter across, huge for
protists. All Soritacea keep
algal endosymbionts, which may be what allows them to achieve such large sizes. Some species have
red algal symbionts, some have
green algal symbionts, and others
dinoflagellate symbionts. These larger symbiont-bearing foraminifera are typically found in the
oligotrophic waters of the tropics.