... are a highly developed grazer of the reef. With strong calcified, fused teeth that scrape off coralline algae and the calcareous surface that most algae live on. They are one of the major sources for the fine calcareous silt found around a reef.
The sponge-like protozoan, Syringammina fragilissima, is 10 cm across and is found 1 km down in the North Atlantic.
