Abstract
Morphological variation in the hydromedusan genus Polyorchis on the west coast of North America is analyzed in relation to gonad number, tentacle number, and radial canal diverticula number relative to the height of the bell. In specimens of Polyorchis examined, it is concluded that P. penicillatus (Eschscholtz, 1829) is highly variable morphologically over its known geographic range from Alaska to Baja California. Polyorchis montereyensis Skogsberg, 1948 is considered a synonym of P. penicillatus, and P. haplus Skogsberg, 1948, is retained as a valid species.