These are among the most common animals living on submerged objects in freshwater habitats. They form lots of colonies of individuals that share the same coelomic space.
Colonies are anatomically simple and easily cloned.
Their life cycle includes sexual and at least two forms of asexual reproduction, with a dormant bud and a well developed swimming phase. Colony growth and development are poorly understood. Preliminary genetic studies have revealed a number of puzzles, the taxonomy needs help, and many fundamental aspects of reproduction, digestion,and respiration are entirely unknown. Working at major museums in the U.S., Europe and India, I think I have now located all type specimens. That material leads to a whole new understanding of certain species and even genera.