There is no brain. They contain a central cavity called the Gastrovascular cavity. Digestion takes place here and the contents are absorbed by the endodermal cells. The undigested food is expelled through its mouth. They contain radial symmetry.
Some organisms are sessile while others are free floating.
They reproduce by budding and regeneration. They also reproduce sexually. They contain both male and female reproductive structures in the same body. They are called hermaphroditic.