Microscopy Primer
Light and Color
Microscope Basics
Special Techniques
Digital Imaging
Confocal Microscopy
Live-Cell Imaging
Microscopy Museum
Virtual Microscopy
Web Resources
License Info
Image Use
Custom Photos
Site Info
Contact Us

The Galleries:

Photo Gallery
Silicon Zoo
Chip Shots
DNA Gallery
Amino Acids
Religion Collection
Cocktail Collection
Screen Savers
Win Wallpaper
Mac Wallpaper
Movie Gallery

Phase Contrast Image Gallery

Obelia Medusa: Second Generation

The elegant medusa jellyfish, illustrated in the photomicrograph below, is one of two forms that the hydrozoan Obelia takes during its two-generation life cycle. The free-swimming medusae reproduce sexually, producing eggs and sperm that fertilize to become ciliated, free-swimming larvae (planulae). The planulae remain pelagic for a period of time, eventually attaching to a surface and developing into polyps.

The polyps are stalklike forms that attach to a surface (usually ocean bottom) by means of rootlike filaments. 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.

Obelia belongs to the phylum Cnidaria, which includes corals, sea anemones, jellyfish, and the freshwater hydra. The many species of this genus are widely distributed throughout all the oceans and are typical of cnidarians, both in their morphology and their life cycle.


Questions or comments? Send us an email.
© 1998-2022 by Michael W. Davidson and The Florida State University. All Rights Reserved. No images, graphics, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders. Use of this website means you agree to all of the Legal Terms and Conditions set forth by the owners.
This website is maintained by our
Graphics & Web Programming Team
in collaboration with Optical Microscopy at the
National High Magnetic Field Laboratory.
Last modification: Friday, Nov 13, 2015 at 02:19 PM
Access Count Since June 4, 2000: 31202
For more information on microscope manufacturers,
use the buttons below to navigate to their websites: