ARNOLD — THE PALEONTOLOGY AND STEATIGRAPHY OF SAN PEDRO 115 



Subgenus Hinnites Defrance. 



Shell (up to advanced youth) a typical Ck/aniys. later becoming- sessile and irregular, in 

 which stage the resilial pit is elongated and the cardinal margin develops an obscure area. 



Type, HinniteH cortezl Defr. 



36. Pecten (Hinnites) giganteus Gray. 



Hinnites giganteus Gray, Ann. Phil., 1826, p. 103. Carpenter, Brit. Assn. Rept. . 1863, p. 675. 

 Gabb, Pal. Gal., Vol. II, 1869, p. 105. Cooper, 7th Ann. Rept. Gal. St. Min., 1888. 

 p. 243. Keep, West Goast Shells, p. 165, fig. 138, 1892. Williamson, Proc. U. S. 

 Nat. Mus., Vol. XV, 1892, p. 193. -f H. poulsoni Conr. ^ (?) //. crassus GoN., 

 {Jide Dall, Trans. Wagner Inst. Sci., Vol. Ill, Part 4, 1898, p. 711) 



Shell large, oval, irregular, inequivalve, subequilateral; surface sculptured by about seventeen 

 irregular, squamose, rounded, prominent radiating ridges, with two or three minor ones between each 

 pair of the large ones. 



Dimensions. — Long. 65 mm.; alt. 65 mm.; diam. 25 mm. 



Adult.s distinguishable from Pecten on account of distortion caused by attach- 

 ment to some object (hiring the later stages of growth. The young, unattached shells 

 of this species much resemble the young of P. hasfalus. but are distinguishable from 

 this species by a less spinose growth on the ribs, and also in having a much 

 heavier shell. 



Rare in upper San Pedro series of San Pedro, Los Cerritos, Crawfish George's, 

 and Deadman Island; a few specimens from the lower San Pedro series of San Pedro. 



Living. — Straits of Fuca to San Diego (Cooper). 



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



Pliocene. — Santa Rosa Island; Ventura County; Los Angeles County (Cooper). 



Family X. LIMlDyE. 



Genus Lima {Britgiiin-e) Cnvier. 



Shell equivalve, compressed, obliquely oval; anterior side straight, gaping, posterior 

 rounded, usually close; umbones apart, eared; valves white, smooth, punctate-striate, or radiately 

 ribbed and imbricated ; there is usually a thin, brownish epidermis ; hinge-area triangular, cartilage 

 pit central ; adductor impression lateral, large, double ; pedal scars, two, small. 



Lima squamosa Lam. is a characteristic species. 



Subgenus Lima .s. .s. 

 Hinge edentulous; valves gaping, inequilateral. 



Section Mantellum Adams 

 Submargins not impressed. 



Type, Liina hiaiis Gmel. 



