Different species occur in a variety of shapes and sizes, some species resemble bath sponges, others are flattened discs or with four branches forming a tetrahedra. They are easy to damage when collected from the ocean depths and cannot be cultured, so their life histories remain largely a mystery. Xenophyophores are known to be quite numerous on the sea floors despite the little we know about them. They are multinucleate masses of cytoplasm and enclosed by a branched tube system. The many nuclei can be 2-10 m m in diameter and are evenly distributed through the cytoplasm.
Fecal matter is accumulated outside the tube system in dark strings of pellets.
There are 42 known species of Xenophyophores in 13 genera. As a final comment , this recent discovery of probably the largest protozoan specimen found to date, illustrates that the ocean depths are still very much an undiscovered frontier for scientists to explore. Ever more sophisticated deep sea submersibles aid this exploration, so who knows what remains to be found. But novel life forms are still being discovered much closer to home than the ocean depths. Apparently a number of foraminifers and marine amoeba-like organisms can grow to 10 mm or more but the majority are smaller than 5 mm.