Belonging to the phylum Coelenterata, the class Hydrozoa is best known for the polyp state, which is revealed, under microscope examination, to form extensive and beautiful colonies. The multiply stained specimen illustrated below is a member of the Pennaria genus, and was captured in brightfield illumination on the MIC-D digital microscope.

Pennaria feature tentacles that occur in two forms: filiform and capitate. The filiform tentacles resemble those of hydra, and are long and tapering, with batteries of nematocysts distributed over the entire surface. In contrast, capitate tentacles occur with their entire nematocyst array confined to a single knob on the tentacle end. In Pennaria, medusa buds (even very large examples) lack tentacles, and the gonads develop in the epidermis of the manubrium.

---

BACK TO THE BRIGHTFIELD IMAGE GALLERY

BACK TO THE DIGITAL IMAGE GALLERIES

Questions or comments? Send us an email.

© 1995-2022 by Michael W. Davidson and The Florida State University. All Rights Reserved. No images, graphics, software, 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 01:19 PM

Access Count Since September 17, 2002: 16534

Visit the website of our partner in introductory microscopy education: