CURVED DATEMUSSEL Modiola (Lithophagus) gruneri R. A. Philippi, 1851 (Aug.): 85; Lithodomus fateatus A. A. Gould, 1851 (Nov.): 92; 1853: 403, pl. 16. Shell cylindrical, very elongate, with attenuate posterior end and irregular vertical periostracal wrinkles. Length to 113 mm. The Gould name A. falcatus has been commonly used for this species, but Carpenter, in Gould and Carpenter (1857) recognized that M. gruneri was a synonym,although he was unsure of the relative dates. Philippi described this species without a locality, and it was attributed in error to New Zealand by Reeve. The similar Japanese Adula falcatoides Habe, 1955, is proportionately shorter, broader posteriorly and more coarsely rugose (Scarlato, 1981: 249). Coos Bay, Oregon (43.4°N) [CAS], to Isla Cedros, Baja California (28.2°N) [CAS], in the intertidal zone to 5 m. Records from Cabo San Lucas, Baja California Sur, are probably the result of a mislabeled station. Usually boring into soft rock or shale, but at Monterey Bay it is also found in hard silicious chert. Reported from the Pleistocene of southern California. Literature: Fankboner (1971), U. S. Grant and Gale (1931: 255-253), Haderlie and Abbott (1980: 357), Haderlie et al. (1974: 202), Hertlein and Strong (1946a: 74), Soot-Ryen (1955: 89-90), Yonge (1955).