These microscopic and near-microscopic pseudocoelomates are common in freshwater environments all over the world (and a few species can be found in salt-water as well). Rotifers have bilateral symmetry and are divided into head, trunk, and foot regions. Their most distinctive feature is the ciliated “corona” on their head. These coronal cilia form a current that sweeps food particles into their mouth. These cilia can also be used to pull the rotifers through the water when not attached to a substrate. One class of rotifer, the Bdelloidea, are assumed to have not sexually reproduced for millions of years – there are actually no males within the species and the females reproduce only through parthenogenesis!