Gonionemus

Gonionemus is a genus of hydrozoans that uses adhesive discs near the middle of each tentacle to attach to eelgrass, sea lettuce, or various types of algae instead of swimming. They are small (bell diameter to 25 mm) and hard to see when hanging onto swaying seaweed. Nevertheless, they are capable of swimming when necessary. The bell is transparent, revealing the four orange to yellowish-tan gonads that lie along most of the length of the four radial canals. The pale yellow manubrium has four short, frilly lips. Up to 80 tentacles line the bell margin, with about an equal number of statocysts. Copepods are a favored prey. Whereas Pacific Northwest Gonionemus vertens lacks a sting felt by people, the same species in the Russian Far East is known to be venomous. This nearshore limnomedusan inhabits quiet waters of northern Japan and Kamchatka (Russia), and the area from Alaska's Aleutian Islands to northern California.