One generation, illustrated in the photomicrograph above, lives in hydroid colonies, consisting of polyps. The polyps reproduce asexually, by budding, and create new polyps until it has formed a treelike colony. The colonies are dimorphic, having two types of polyps. Gastrozooids, or hydranths, are the feeding polyps. They have a mouth surrounded by stinging tentacles, giving them a flowerlike appearance, and are responsible for capturing and consuming food.
Food is digested in the gastrovascular cavity and provided to the rest of the colony.
The second generation of the life cycle begins when the medusae are released by the gonozooids and become free swimming forms. The planulae remain in a free-swimming form for a period of time, eventually attaching to a surface and developing into polyps. All Rights Reserved . No images, graphics, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders.