Intertidal sea anemones (Cnidaria: Actiniaria) from the west coast of the Peninsula of Baja California, Mexico.

Nine species of sea anemones are documented from the west coast of the Peninsula of Baja California. Short descriptions of Anthopleura artemisia (Pickering in Dana, 1846), A elegantissima (Brandt, 1835), A. sola Pearse Francis, 2000 and Epiactis prolifera Verrill, 1869 are provided, including images of the external and internal anatomy, as well as cnidae. In addition, an updated list of the sea anemone species recorded in Mexico, including both the Pacific and Atlantic regions, is provided. The northern species A. artemisia and E. prolifera are recorded for the first time in Mexico. With these new records, the number of sea anemone species known in the Mexican Pacific increases to 35, and to 57 for the entire country.