Scyphozoa sp.

Description and links to related Cnidaria.
http://www.ucmp.berkeley.edu/cnidaria/scyphozoa.html

Jellies Zone

Guide to gelatinous zooplankton of the U.S. Pacific Coast, with photos and information on jellyfish (true jellies), comb jellies, gelatinous molluscs, and pelagic tunicates.
http://jellieszone.com/