Sifterfort

The sifterfort split from its ancestor and now has a large membranous sifter that it uses to collect dissolved iron out of the water. It has a pocket attached to the cell wall that fills with water when the sifter is out and empties rapidly to pull the sifter back in. Its cell wall is much thicker to protect against predators, and the sifter has an iron cap on it so the cell is completely enclosed when in defensive mode.