When you are starting to study marine life, it's easy to confuse the two. But when we use a microscope, we can discover their delicacy of details and subtle differences. If kept undisturbed in seawater, individuals come out from their protective envelope and deploy tentacle rings. Bryozoans are discussed in this page and cnidarians in the following page. This tuft of tentacles is called the lophophore and can be retracted quickly by a strong muscle fixed into the envelope.
Cilia movements conduct food particles down toward the mouth.
The name's origin is probably because they look like a bird's beak. Normally avicularia adopt an open 'beak' but sometimes the beak is quickly closed, maybe when an object touches a tuft of hairs located in the middle. Yet bugulas tolerate well any vorticellas or suctorias that are present. The picture left shows an avicularian on a Bugula species. Reproduction gives rise to rounded ovicells, called ooecia.