Xenophyophorea

Xenophyophorea /ˌzɛnəˌfaɪəˈfoʊriːə/ is a clade of foraminiferans. Members of this class are multinucleate unicellular organisms found on the ocean floor throughout the world's oceans, at depths of 500 to 10,600 metres (1,600 to 34,800 ft). They are a kind of foraminiferan that extract minerals from their surroundings and use them to form an exoskeleton known as a test.

They were first described by Henry Bowman Brady in 1883. They are abundant on abyssal plains, and in some regions are the dominant species. Fifteen genera and 75 species have been described, varying widely in size. The largest, Syringammina fragilissima, is among the largest known coenocytes, reaching up to 20 centimetres (8 in) in diameter.