What is Hydrozoa?

The Hydrozoa are the second largest group of Cnidarians, and they have some of the coolest species.  This difficult to describe group of animals is defined by having a planula larvae, which is a specialized, flat, and free swimming larvae. The hydrozoa can live solitary and colonial. The colonial species tend to form interesting structures where all the animals rely on each other for survival.

The Hydrozoa contains a really cool group of animals called the Siphonophores. To learn all about the Siphonophores and other cool animals be sure to go to the Animal Wonders of the World section of our Kids' Zone.

Air ferns are also Hydrozoa.  Not sure what an air fern is? Be sure to check that out in the Air fern section of the Kids' Zone! You can also learn more scientific keywords to impress other Defenders at the Glossary.


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