They live on substrates in shallow warm (>20 °C) euhaline tropical marine waters, usually less than 20 meters deep, and protected from waves.

Only when they are ready to produce gametes does the nucleus undergo meiosis and then numerous mitoses into many nuclei which then migrate into the gametangia at the top of the alga.

These algae are notable for having an intracellular network of 10 nm proteinaceous filaments, possibly for the storage and transport of ribonucleoprotein particles.

[6] Because of all these properties, and the fact that they are easy to manipulate they have been favorite organisms in the study of the role of the nucleus vs the unnucleated cytoplasm in the behavior of cells.

Proposed Cambrian representatives (questionable) include:[5] - Cambroporella - Amgaella - Yakutina - Seletonella - Mejerella [5]