AKNOLD— THE PALEONTOLOGY AND STItATIGRAPHY OF SAN PEDKO. 117 



" Shell adherent, subequivalve. irrej^ular, flattened; hinge with two thick, divergent, elongated 

 lamella in the inferior, corresponding with two long pits in the upper valve; upper valve with only 

 two muscular impressions; the pedal scar radiately striated "; surface with incremental lamina- and 

 sometimes radial ridges. 



Pari i)( the uhovc description was taken Iruiu Ti-yon. This species resembles 

 Anomiii lampe, but may be distinguished by its greater size and fewer muscle-impres- 

 sions. Specimen identified by Dr. Dall. 



Rai'c in tlie njiper Kan Pedro scries of San Pedro, Crawfish George's, and 

 Deatlnian Island. Found also in the Pleistocene of the bluff west of the bath-house, 

 at Santa Barbara. 



Living. — Unalaska to San Diego; Japan (Cooper). 



Pleidocene. — Santa Barbara to San Diego (Cooper): San Pedro (Arnold): 

 California; Oregon; Alaska (Dall): Santa. Barbara (Arnolil). 



Pliocene. — San Diego well (l^all). 



Miocene. — Sooke, Vancouver Island (Newcombe). 



Genus Anomia Linne. 



Shell suborbicular, translucent, attached by a plug passing through a hole or notch in the 

 right valve ; upper valve convex, smooth, lamellar, or striated ; two byssal scars on the disk, main 

 byssal scar largest; foramen open, ample ; hinge unarmed. 



Anomia ephippiinn Linne is a characteristic species. 



39. Aaomia lampe Gray. 



Anomia laitipe Gray, Proc. Zool. Soc, 1849, p. 114. Carpenter, Brit. Assn. Rept., 1863, p. 646. 

 Gabb, Pal. Cal., Vol. II, 1869, p. 106. Cooper, 7th Ann. Rept. Cal. St. Min., 1S88, 

 p. 229. Keep, West Coast Shells, p. 163, 1892. Williamson, Proc. U. S. Nat. Mus., 

 Vol. XV, 1892, p. 194. Dai.l, Trans. Wagner Inst. Sci., Vol. Ill, Part 4, 1898, p. 785. 



.Shell of medium size, suborbicular, thin, translucent and slightly pearly within ; surface of 

 left valve sculptured with fine, irregular, concentric lamellar lines and several prominent, irregular, 

 rounded, radiating ridges; interior of this valve with submarginal cartilage pit and four muscular 

 impressions; right or lower valve concave, with a deep rounded notch in front of the cartilage process. 



Dimensions. — Long, and alt. 48 mm.; diam. 9 mm. 



This species is variable both in regard to its shape and its sculpture, but is 

 easily distinguishalde by the thin, lamellar, translucent shell. Distinguishable from 

 A. limatala Dall by its smaller size and radial ridges. Specimens identified by 

 Dr. Dall. 



Common in the upper San Pedro series of San Pedro, Los Cerritos, Long 

 Beach, and Crawfish (Jeorge's; rare in the lower San Pedro series of Deadman Island 



