The athecate hydroid Bimeria franciscana Torrey has been found in estuarine habitats throughout the world. For this study B. franciscana was collected along the docks of the Petaluma River, California, a new collection site. Investigations on the appearance and biology of this hydroid have not been recorded in this area, perhaps because of its relative rarity along the river Distribution records and synonymy of B. franciscana as well as general taxonomic characteristics of the species of the Genus Bimeria present on the west coast of the United States are assembled in a series of appendices added to this work. This compiled information, along with the information on B. franciscana presented in this paper, are then compared as a basis for clarification of the confused taxonomy of the Family Atractylidae.