ARNOLD — THE PALEONTOLOGY AND STRATIGRAPHY OF SAN PEDRO 115 



Subgenus Hinnites Def ranee. 



Shell (up to advanced youth) a typical Ch/atnys, later becoming- sessile and irregular, in 

 which stage the resilial ])it is elongated and the cardinal margin develops an obscure area. 



Type, JJinnitefi cortezi Defr. 



36. Pecten (Hinnites) giganteus Gi-ay. 



Hinnites giganteus Gray, Ann. Phil., icS26, p. 103. Carpenter, Brit. Assn. Rept., 1863, p. 675. 

 Garb, Pal. Cal., Vol. II, 1S69, p. 105. Cooper, 7th Ann. Rept. Cal. .St. Min., 1888 

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

 Nat. Mus., Vol. XV, 1892, p. 193. + H. poulsoyii CoNR. = (?) //. crassus Con., 

 {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. 



Adults di.«!tiiiguisliahle from Pecten on account of distortion caused by attach- 

 moiit to some object durinp; tlie later stajjes of growth. The young, unattached shells 

 (if liiis species much resemble the young of P. lumtalm^. but are distiiiguislinlile from 

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

 lieavier 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. LIMID^. 



Genus Lima {Bruguiere) Cuvier. 



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 epidermi.s ; hinge-area triangular, cartilage 

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



Lima squainoi^a Lam. is a characteristic species. 



Subgenus Lima .«. s. 

 Hinge edentulous; valves gaping, inequilateral. 



Section Mantellum Adams. 

 Submargins not impressed. 

 Type, Li7na hians Grael. 



