Midwater Hydromedusae

Photos and descriptions of midwater and deep-sea hydromedusae in Monterey Bay, California.
http://www.mbari.org/~kraskoff/medusae2.htm

Obelia colony

Photo.
http://www.ou.edu/class/invert/colony.htm

Horia's Marine Biology Page

Personal marine biology site with photomicrographs of some marine hydroid species, urchin (Paracentrotus lividus) development, and other marine invertebrates.
http://www.chez.com/biologypassion/horia/

Obelia Laboratory Exercises

Anatomy, with illustrations.
http://www.lander.edu/rsfox/310Obelia.html