C. E.  Mills, ?Additions and corrections to the keys to Hydromedusae, Hydroid polyps, Siphonophora, Stauromedusan Scyphozoa, Actiniaria, and Ctenophora?, in Marine Invertebrates of the Pacific Northwest, with Additions and Corrections, E. N.  Kozloff and Price, L. H., Eds. Seattle: University of Washington Press, 1996, pp. 487-491.