Made from calcium carbonate, the Skeleton of bryozoans come in a variety of shapes and patterns, ranging from corkscrew to lacy fans shapes. Their skeletons contain numerous small openings which holds minute animals called zooids. They have a coelomate body with a looped alimentary canal, a mouth, anus, and lophophores.
The mouth opens into a U-shaped gut; the anus is located just outside the lophophore. From this arrangement comes the alternative nam
e for the Bryozoa, the Ectoprocta. The body also contains a coelom and gonads; there is a small central ganglion but they lack specialized excretory or respiratory systems.
Zooids are usually connected to each other by thin strands of tissue. There are four types of zooids typically found in a colony. Each integrat
ing with one another and help the colony with its own particular function:
- Autozooids: Food gathering zooids. Called “feeding zooids”
- Heterozooids: Dependent on autozooid for gaining nutrients. They are also specialized zooids (producing eggs, protection etc.)
- Kenozooids: Provide strength and support
- Vibracula: Clean the bryozoan colony
Colony Contributing to protection, het erozooids have Avicularia whic are small heterozooids having zooecium and operculum formed in a beak like snapping structure. Vibracula on the other hand contains long setae that function in cleaning the colony.
