The study of several series of specimens belonging to the Orbiniidae has indicated the need to modify the definitions of some of the genera of this family. Since the monographic work of Eisig (1914) on the systematics and morphology of the Ariciidae ( = Orbiniidae), the family name and general systematics used in that revision have been followed by most workers. Some genera have been added to the family, however. The following revision includes those genera that were represented by material available for study in the United States National Museum. Three new species of orbiniids are described from the east coast of North America and one from the west coast. A new subgenus is proposed and new names are given for two species. The types are deposited in the United States National Museum.
[None. Introduction as follows:]