CALIFORNIA DATEMUSSEL Modiola californiensis R. A. Philippi, 1847: 113, ex Eschscholtz MS; Adula stylina Carpenter, 1864c: 644; 1864d: 425. Shell elongate, cylindrical, with commarginal striae only; posterodorsal slope with heavy periostracal mat. Length to 60 mm.
Graham Island, Queen Charlotte Islands, British Columbia (54°N) [RBCM], to Point Loma, California (32.7°N) [LACM], in the intertidal zone. Found boring in shale and other soft rocks. Recorded in the Pleistocene of western North America. The species does not occur in the northwest Pacific, and material from the Sea of Okhostk and Japan that has been given this name should instead be referred to A. schmidtii (Schrenck, 1867). Literature: D. P. Abbott and Hilgard (1987: 177-178), Haderlie and Abbott (1980: 357), Lough and Gonor (1971, 1973), Soot-Ryen (1955: 90-91), Strathmann (1987: 321), Yonge (1955).