112 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 23 



Pecten (Chlamys) latiauritus fucicolus Dall. Oldroyd, 1924a, p. 58. 



[Under "Section" Leptopecten.] 

 Pecten cf. latiauritus fucicolus Dall. Li, 1930, p. 255, pi. 2, fig. 11. 



"Mouth of the Rio Grande near La Boca about one mile from the 



mainland in Panama Bay." [= Pecten tumbezensis d'Orbigny, fide 



Pilsbry, 1932, p. 429.] 

 Pecten (Aequipecten) latiauratus Conrad var. monotimeris Conrad. 



Grant & Gale, 1931, p. 204, pi. 4, figs. 3, 6. Previous Pleistocene 



and Recent records. 

 Chlamys (Plagioctenium) latiauritum [«c] var. monotimeris Conrad. 



Bavay, 1936, p. 315. 

 Pecten (Leptopecten) latiauratus monotimeris Conrad. Proc. Conch. 



Club So. Calif., 1944, no. 35, p. 9. [Same records as Dall, 1931] — 



Hertlein & Strong, 1946, p. 60. Monterey Bay, California, to Cape 



San Lucas, Lower California. 

 Leptopecten latiauratus Conrad. Morris, 1952 [ex parte], p. 16, pi. 1, 



fig. 3; pi. 5, fig. 4. [Figures = Chlamys (Leptopecten) latiaurata 



monotimeris (Conrad)] — Abbott, 1954 [ex parte], p. 365, pi. 34, 



fig. i. [Figure = Chlamys (Leptopecten) latiaurata monotimeris 



(Conrad).] 

 Holotype: Academy of Natural Sciences, Philadelphia. 

 Type locality. San Diego, California. 



Original description: Shell ovate, oblique, thin, compressed, w^ith 

 concentric striae ; ribs thirteen, rounded ; ears subequal ; colour brown, 

 with white stripes and spots. 



Var. A. Orange, with white divaricating stripes. 

 Inhabits with the preceding [latiaurata]. The j'oung occasionally 

 found attached to Fuci by a slender byssus. 



Additional description: Shell veiy thin, moderately to extremely 

 oblique, convexity moderate, length and height about the same ; adult 

 specimens averaging 28 mm in altitude, occasionally 38 or 40. Hinge 

 line % to y^ length of disk. Right valve more convex than left. Both 

 valves with 9 to 13 broadly rounded ribs (actually corrugations of 

 disks), somewhat higher on left. Ribs and interspaces almost always 

 smooth, but sometimes having distant concentric growth lines or striae; 

 distinct radial ridges only very infrequently present on ribs and in inter- 

 spaces. Posterior auricles longer than anterior, with varying number of 

 low radial ridges, finely concentrically striated. Anterior auricles, though 

 shorter than posterior, produced to margins of disks and occasionally 

 beyond ; that of right valve having 3 to 5 imbricated riblets, that of left 



